Yaz's Rebuild

Need to start off by thanking the members of this forum. Especially the heavy hitters. Goal of this thread will be to document the symptoms, discussions, decisions, and eventual results. Don't intend to make it a step-by-step as Jake has that covered with the video series.... Vehicle is a 2001 C2, so starting off with a 3.4L M96 (I'll get into the acquisition of the car in a later post). Started the car up Cinco de Mayo 2019 after the spring showers had washed the salt off of the southeastern CT roads (love the back roads and lack of traffic around here). Nothing unusual on the first drive. Put it back in the garage. Fire it up again later that day to grab dinner with friends, and within the first mile lots of white smoke out of one tail pipe. Back into the garage. Spend the next couple weeks doing some intermittent online research. Decide to drop it off with my German indy who took great care of my old BMW X5. He tells me there's coolant in cylinder 3, and that it's a blown head gasket (the more versed forum members know where this is going). Well sie german starts making excuses about an upcoming back surgery/not wanting to take on the work and refers me to his friend who specializes in exotics in the New Haven area. He tells me the typical price for engine out work. At the time I'm fairly busy with work and building out my new 4Runner so I thankfully hold off on having any work done... So September rolls around and we're back from an epic trip in the 4Runner out to South Dakota/Montana/Idaho (winch paid for itself and the GF can no longer complain about my time and money spent on vehicle builds ). Now it's time to figure out the white smoke problem. My old neighbor had previously mentioned his brother-in-law was a long time Porsche guy/mechanic. Let's give him a call... "Head gasket?! Those engines don't blow head gaskets. You've either got a cracked cylinder head or liner." Thank you Buck. Now down the rabbit hole (You guys will notice I joined in September)... Hope you all enjoy!!!

Yeah the head gaskets are metal, they can only fail from corrosion which is rare.

After getting deep into the research, it's pretty clear we're not dealing with a head gasket problem. Realize my options come down to a replacement or rebuilt engine. More research, more reason to be wary off a replacement engine. Buck also told me it wasn't worth the money to rebuild the engine. Or at least to pay someone to rebuild the engine (unless it's Jake). So how much is this car worth to me? And the related question, how did I acquire it? This was my dad's first Porsche. He bought it after he'd walked through his own nine circles of hell. I can't express how much I love and appreciate him. (Got a little emotional there). So anyway, he had the 996 in Seattle and a 997 in a LA. My parents decided they were done with Seattle, and business-wise it didn't make as much sense to keep a place in LA. So pops is probably getting rid of a car. Like the great son that I am, I treat my dad to an F1 weekend in Montreal, and negotiate the transaction over some overpriced Heineken's in the Senna corner. Not a Hamilton fan, but pretty cool seeing him gifted Senna's helmet by the family.

I have a Rebuilt 2001 engine for sale with LN 3.6 sleeves, here's a link that shows what was done: https://rennlist.com/forums/996-foru...rebuild-7.html

So now getting into October 2019, I'm pricing out my options. Read thru some of the DIY engine build threads on here (couple useful links below. Again can't thank this forum enough). Also get wind of Jake's engine assembly video series. https://rennlist.com/forums/996-foru...engine-34.html https://rennlist.com/forums/996-foru...under-10k.html Figure it's time to talk to Jake. Great conversation with him. For anyone even remotely questioning if they have a time and space for a rebuild, go with him. When this build is all wrapped I'll share my costs, but when you factor in the time to properly research it's a no brainer on the value he offers. Anyway... " Yeah, you've got a cracked cylinder" (We'll get into the teardown eventually)

Decision was made to drop the engine sometime in November before it got too cold. I'm a hockey player and skier, and used to not being able to feel my hands and feet, but auto work is a different animal when it's cold. I borrowed a buddy's floor jack and did some Harbor Freight shopping for a few other items. Used 4 of the 6-ton jack stands from HF set around 22", low lift transmission jack, floor jack with a cross beam, and a couple hockey pucks. Here are the links: https://www.harborfreight.com/automo...nds-61197.html https://www.harborfreight.com/automo...ack-61232.html https://www.harborfreight.com/automo...eam-60762.html I didn't have to remove the intake manifold, but it was a consideration if I was short on clearance. Engine height is about 26" from top of manifold to bottom of the sump. Removing the rear bump including the aluminum piece buys you about 10". The hockey pucks were used on top of the cross beam to support along the edge of the sump when dropping the engine. When jacking the vehicle, I initially got the front jack points on 15" stands. After that I was able to use the cross beam to reach the points just outside the center brace for the rear and both reinforced locations in the front. Also considered the 12-ton stands, but I found the 6-tons stable at the height I had them. Here's another useful thread: https://rennlist.com/forums/996-foru...dations-3.html

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Pretty tempted to buy the http://liftbars.com/

Apparently I didn't take any pictures off the oil and coolant. Oil was a milkshake, but fortunately the coolant was clean.

Up onto the engine stand. Another HF special Teardown to the long block Nice pile of parts in the corner. Yes, I was diligent about tagging everything. Crazy how much fits into the *** end of a Porsche

HF had a convenient (and cheap) 24 bin container for organizing and identifying the lifters.

And now for the money shot. As I mentioned in Scott's rebuild thread, its a little bittersweet seeing that crack. Knowing the rebuild is more extensive, but having the excuse to GO BIG!!!

Good luck with the build!

Nope, the head gaskets are stronger than the cylinders, and the heads... As depicted in your photo. Mode of failure #2, cracked cylinder... Good luck, and buy my video!

Are you doing the build yourself? Yes, great excuse to big bigger...and better! Subbed.

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Just to clarify... already bought Jake's videos (the second they went live on Amazon. Watched them twice already. In hindsight probably should have gone with the DVDs) and I'm doing the build myself.

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Recently turned 38. Upgrade to 3.8L is only fitting.

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Ghats great to hear. Last week the first two builds from DIYr�s using my video were completed. There�s 2 more almost finished. I love hearing success stories from those who have used the videos as I intended them.

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Awesome work on the videos Jake. Actually already have my heads back from Hoffman and my Nickies from LN. More detail to come. Playing catch up at this point.

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Wow. Where have I heard this song before? Nice to see your thread, Yaz. You're ahead of me in the build process. Hopefully all goes well. The build videos will definitely keep both of us out of the weeds. We're all pulling for you. Keep your stick on the ice.

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Sounds like you are almost there!

Biggest challenge at this point is convincing the girlfriend the engine build needs to start in the dining room so I can maintain the right temp. Granted she already hates the pool table in there.

You visited my state and didn't say hello? How rude.

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That pool table should make a steady workbench. Just put plenty of paper down.

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My DVD set just arrived and I can't wait to watch them this week. I need to keep one lump up and running while the other goes on vacation! Thank you for getting this done for us. Unfortunately, I don't have the time, space or tools to do my own rebuild...Jake's going to take this on for me (I hope ) at the end of the year.

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Best of luck Yaz and thanks for documenting another rebuild!

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Where in ID are you? Parents live in Sun Valley. Drove in from Big Sky through Idaho Falls, and left north via the Galena pass. Would have loved to be in a 911 for the drive.

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Oh cool. I'm in Boise. Wife and I actually make the Sun Valley run a couple times a year for vacation. It's one of our favorite places. Last year we did drives to Sun Valley and Coeur d'Alene. The Targa makes a fine touring machine!

Nice progress! Keep it going. If you have a basement with a furnace room, set up shop in there. Just get a foldable table, a chair and a light. Put the shorblock together in there and then bring all up to the garage to finish. Get a dolly made to move water heaters up and down stairs and that will be good enough, with two people, to bring the shortblock upstairs. That's what I did, it was the best decision I've made when it comes to putting and engine back together in comfort. To keep the smell down, I've used vegetable oil to lube things up while the engine was in the house.

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What viscosity vegetable oil?

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My basement is finished and heated, but I actually think the pool table is the better option. I have a dining table conversion top for it and space around it for my engine stand. Would make for a nice work space. Hadn't considered the smell. Already picked up some Driven HVL and assembly grease. I'll need to give it a whiff when I get home. I was in your neck of the woods during my August road trip. Grabbed dinner in Kitchener at Moxie's with my old college goalie/roommate.

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Dollar Tree viscosity! The crank carrier was already assembled with proper lube before I brought it into the basement and was sitting like that for 3 years so the that didn't smell much. The only thing I've used the vegetable oil was to slide the pistons into the bores. Once the longblock was back in the garage, I used engine oil to re lube the bores before the heads went on.

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That's an interesting point. I was watching the Raby video where he used a "special lube" for rings and pistons. I'm curious what he uses. I'll bet it's another closely guarded secret.

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Hey, it might not be the right way....but it is my way! And she never complained that the house smelled like an oil spill.

Anyway back to the teardown... Had a little trouble getting the front console off and unfortunately broke it. Jake warns about this piece being fragile in the assembly videos. I was able to find the part new (with the upgraded oil pressure relief valve) for about $340.

Damn! That sucks.

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Yep. as you reassemble using my method in the video, note that everything I focus on is done to avoid complications that will lead to this breakage. Also, guys.... Never compromise assembly procedures because of something like a smell. Vegetable oil has no properties that will carry load during initial engine start up. If it smells, get over it- if you make a compromise you�ll pay for it. Suck it up, buttercup.. This is engine building, you have one chance to get it right, or you get to do it again.

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So Jake, can you share a clue as to what's in your piston/ ring lube? I don't care about the smell.

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Here's a clue: LN Enginnering.

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So if I said; "BR40", would I be getting warm?

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Yes, but check the website alot has changed since I broke in a rebuilt engine.

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I visit there frequently. I have not found anything specific to engine assembly oil. They list a high viscosity lube and an assembly grease. The special lube that I saw in the video did not look to be of high viscosity, and it certainly was not grease.

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Only used the it to slide the pistons into the bores. For the rest of the top end I used some 85W140 that I had left from a Jeep differential swap. It's extreme pressure gear oil so should be better than the Dollar Tree one

I was planning to use BR40 for the pistons and rings.

How about this... https://lnengineering.com/rnd-store/...ket-00734.html

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A packet of that came with my IMS Solution. Also grabbed an extra 1oz tube. Hope that will be enough.

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Wouldn't this cover it? https://www.drivenracingoil.com/asse...-1-lb-tub.html and this... https://www.drivenracingoil.com/hvl-...bricant-1.html

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I purposely did not divulge any of the lubricants, and sealants used. Why? Because these change, and the video would suffer from that. Plus, there's a ton of component manufacturers out there, and they all have different recommendations. As an example, Total Seal Piston rings has their own lubricant that Driven made for them. I am not big on using special, very thick lubes. Vegetable oil is for cooking, not engine building. Don't use it.

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Thanks for the reply, Jake. I would never consider vegetable oil. There's no worry there. Now, olive oil... Yes - I noticed you stress the fact that you intentionally do not state which lubes and sealants, etc. you use. I'll wait to see what the recommendation is when I get the pistons and rings from LN. I suspect it will be Driven BRx oil. If they don't have a recommendation, that will be my fall-back.

So I'll actually be using Total Seal rings, and now I'm seeing they recommend their Quick Seat dry film lubricant and own branded assembly lube (also formulated by Driven). Curious how those assembly lubes differ. Secret sauce indeed.

"Vegetable oil is for cooking, not engine building. Don't use it." How about extra virgin cold pressed olive oil? It's really expensive... and of course it tastes good - why wouldn't my engine like it? Uh, sorry I just couldn't pass on that one - Just another Porsche-Hole !

Just to wrap up the teardown portion of the thread so we can move onto the fun stuff. No real surprises. The crappy plastic connecting piece broke (no pics, but going to upgrade to the aluminum part). Can you guess which cylinder was cracked based on the piston? Split the crank carrier. Some visible wear on the bearing. Not really sure what would be considered normal after 114k miles. Bag, tagged, and boxed. Big pile of parts organized so I could role the Porsche back into the garage for winter.

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I'm not clear on what plastic piece broke. Is that the AOS coolant pipe? Yes - I can guess. Those bearings do seem to have more wear than you might expect, but at least even. It will be good to start fresh.

Are you going to go with coated bearings in the new build?

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This one... https://www.warehouse33auto.com/cata...996-106-226-52

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Yup. My philosophy is that relative to the overall cost of the rebuild it's worth spending the extra money on upgraded internals.

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Yes - that's it.

You need to be especially watchful of the running clearance on the #6 main. It looks too tight to me, based on the condition, and wear patterns of the main bearings. Reading wear is where some of the black art comes into these processes. As far as being sensitive to smells and using wildly odd things as assembly lube... Well, if you are that sensitive to smell, then engine building isn't for you. You'd probably be better suited with some virtual engine building program, like desktop dyno. If smell is a concern from a workspace perspective, and you must suffer compromises that force you to use assembly lubes, or sealants that don't smell bad, then you lack the proper workspace to build an engine, and therefore engine building isn't for you. Just calling it as I see it. If you have to compromise the process for any reason, this isn't for you. A couple of weeks ago some guy called and literally told me that he was afraid to push the main bearings into the crankshaft carrier firmly because he was concerned about "breaking a nail". My response undoubtedly scarred him for life. Really?

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Thanks Jake! I'll dig deeper looking into the running clearances. Also I wouldn't dream of using anything inappropriate for lubes and sealants. Any thoughts on using a dry lubricant like Quickseat? Regarding workspace I've got three potential locations, but really want to maintain the 72 deg temp throughout the build so the garage is out. Think the smell from my hockey gear already designates the house a hazmat area.

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I can't make any recommendations for what to use, not for oil, or assembly lubes. People will search this forum years from now and dig up what I said, and things will have changed by then. The only way you can't go wrong is by directing these questions to the manufacturers of the components that you are using. It's their product, and it's their place to support that product.

" Just calling it as I see it. If you have to compromise the process for any reason, this isn't for you. A couple of weeks ago some guy called and literally told me that he was afraid to push the main bearings into the crankshaft carrier firmly because he was concerned about "breaking a nail". My response undoubtedly scarred him for life. Really?" ^^^ That's classic ! ^^^

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I may, or may not have referred to him as a "*****" on the phone. He asked for it. I'm sure he probably had a lumberjack beard, was wearing a plaid shirt, with skinny jeans, and had a man bun. He probably "moisturizes" 3 times per day.

Sweet Jeebus! My vegetable oil post got blown out of proportion real quick. To the OP, keep going dude! The piston that had the cylinder cracked, doesn't look like it ran for long with lots of coolant going into it or else the piston top would look brand new.

I may have to drive to Georgia and shake the hand of Jake. What a riot.... keep posting and thanks for the support for the 996's.

" I'm sure he probably had a lumberjack beard, was wearing a plaid shirt, with skinny jeans, and had a man bun. He probably "moisturizes" 3 times per day." Sounds like Brooklyn (and I'm sure some sections of Atlanta)...

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I'm betting on - did. WTF? Worried about breaking a nail? Does his mommy still wipe his *** too?

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You won't find me I escaped to my lair, and it's so remote that your GPS won't even bring you here!

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So now for the fun stuff... First parts to get sent out were the cylinder heads. Got them down to Len Hoffman in early December, and got them back early February. Focus was to get the heads to really complement the bump to 3.8L. Ended up going with the oversized intake valves, Stage 1 porting (intake side only), and new guides and springs. Probably overkill. What really sold me was him saying "This will be the cheapest power you're adding to the motor" Pool table (covered) should make for a decent workspace Oversized intake valves (38mm vs 37mm) Stage 1 porting on the intake side. Nothing done on the exhaust side

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You've just described half of the male population I have to suffer out here in SF.

Next thing to get shipped off was the IMS to LN for their rebuild service. Also took advantage of their Black Friday sale and saved 20% on the IMS Solution. Actually got it back within a week.

Engine case made it to LN a couple days before Xmas. Had them back with 101mm Nickies in just under 7 weeks. George was pleasure to speak to throughout the process. Should be doing the pre-build cleaning shortly.

So now we're all caught up. Calibration weights were delivered today so I weighed the JE pistons and wrist pins. Shouldn't have any problem pairing this set Pistons: 438.4g 438.5g 438.8g 438.5g 438.4g 438.8g Wrist Pins: 89.3g 89.3g 89.5g 89.4g 89.3g 89.4g Waiting to weigh the connecting rods until I finish 3D printing some pieces for a balancing rig.

..

Finished 3D printing some parts to make my connecting rod balancing rig. Also used a couple parts from a dial indicator base and hardware from a luggage wheel kit. Cost me under $10 all in. If anyone want to 3D print their own, I'll share the part files. Pre-assembly Small end setup Big end setup

Nice. I was going to use nails in a 2x4.

Put the balancing rig to use, and pretty impressed with the connecting rod weights. The Carrillo card in the box specified the weights (all in grams) as: Total 563 Rotating 394 Reciprocating 169 My measurements on the total weight were within a gram of the spec. Rotating and reciprocating weights were all pretty close as well. Also calculated the difference between the total and the sum of the rotating and reciprocating. Little off, but consistent at least. Still trying to decide if I should have a local shop balance the whole assembly or just the crank. Total Rotating Reciprocating Delta 563.8 394.5 167.9 1.4 563.4 394.7 167.6 1.1 563.3 394.3 167.9 1.1 563.7 394.5 167.9 1.3 563.7 394.6 167.7 1.4 564.0 394.6 168.0 1.4 Apologies for the lack of formatting.

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I've got a tendency to go overboard on little things. Fun side project though. It can be pretty mesmerizing seeing a 3D printer in action.

What was Jake's line? "Assume nothing, quantify everything"? Broke out the micrometer. All the coated rod bearings measured within a ten-thousandth of each other (0.0593" +/- 0.0001") at the thickest part and two ten-thousandths at the thinner edge (0.0580" +/- 0.0002") . Also all weighed within a tenth of gram (16.0 +0.1 g). Time for a break to take my dog to a new brewery...

Main bearings all measured very close as well. 0.0988" +/- 0.0001" in the middle and 0.0975" +/- 0.0002" at the edge.

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The real test is running clearance, measured in 3 axes with a dial bore gage. The biggest variable here is the machining of the crankshaft carrier, which does heavily impact running clearances.

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Thanks Jake. I'm going to try measuring the clearances later today. Currently limited to a set T gauges though. Deciding if I should buy a quality dial bore gauge since I'll most likely be having a local shop do some work on the crank and carrier anyway.

yaz - you did your prep to check the tolerances for the pieces. Now let the folks doing the crank carrier get the 3D clearances perfect...unless you get bored waiting around.

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Can't say I'm bored, but there's no hockey on today for a couple more hours.

And more measurements...checked all the journals on three different axes. Any out-of-round is less than the accuracy of my micrometer. Main Journals #1: 2.3614" #2: 2.3614" #3: 2.3613" #4: 2.3613" #5: 2.3613" #6: 2.3613" #7: 2.3613" Con Rod Journals: #1: 2.0858" #4: 2.0858" #2: 2.0860" #5: 2.0859" #3: 2.0859" #6: 2.0860"

So for all those experienced in the dark arts of bearing clearances... Realizing that T gauges are insufficient for properly measuring bores, let's just go from Carrillo's BE bore spec supplied with the connecting rods of 2.2047". Measured all the connecting rod journals at 2.0859" +/- 0.0001". That leaves me with 0.1188" for bearings and clearance. Measured the bearing halves at 0.0593 at the thick part and 0.0580 at the edges. Based on the math alone (I realize measurements will be different with bearing in the rods and torqued), I'm left with a max clearance of 0.0028 and a min of 0.0002 (that can't be right). So I did put bearings in one connecting rod, torqued to spec, and actually took some measurements at multiple points (still using T gauges), but it's all over the place. Clearances range from 0.0015" to 0.0046". Crank and carrier will be going out to be properly measured and honed, but for my own education I'd appreciate any comments/links/guidance.

Plastigauge is pretty good for this. I'm sure the purists will have a different opinion.

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It has nothing to do with being a purist, and everything to do with precision. Plastigage may give you a total clearance, IF you can use it correctly, but it doesn�t help with judging concentricity of the bore. You could try to move the area where the material is collected, but in my experience the results are marginal at best. A dial bore gage and micrometer set are essential to precision engine building, whether it�s a Porsche, or a Briggs and Stratton. Doesn�t matter.

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True, it won't help rule out non-concentricity.

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Being concentric is the biggest issue, especially with the main bearings due to crank carrier deviations.

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Rod bearings are always measured at 90* of the parting line. The measurement at the parting line is always off due to the decreasing thickness of the bearing shells (they are actually oval shaped when assembled) . The big end rod housing should be perfectly round when assembled and torqued, but at high RPM it will oval due to stress and is why the bearing shells are ovaled to keep from pinching at high RPMs. Your min clearance of .0015 is too tight, it's better to be a little loose than a little too tight. ( may not be accurate measurements) The bearings are what they are, there are not any "select fit" bearings available for M96, but if you are really too tight, it would not be because the crank journal "grew" while in operation..lol .. They wear down and get looser.

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Thanks. Did a deep dive on bearing clearance and measurement since I last posted and figured most of that out. Also stopped by the local auto machine shop on the way into work this morning, and had a good discussion regarding the build. Going to drop off parts with them to check the clearances and balancing in the next couple days. On a side note, I think I want to add your UAOS to the build.

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Cool !! Go here https://rennlist.com/forums/the-renn...2063-uaos.html to order and get on the wait list. They are Custom built , so takes a little time.

Dropped off the crank/carrier and rotating assembly for polishing, balancing, and clearance measurements at the local shop this morning. From what I've gathered, clearance on the mains should be 0.0023-0.0028", and on the rod bearings 0.0021-0.0026". Those numbers seem right?

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Where did the shop get those numbers from?

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Those are just numbers from various publications by bearing manufacturers. I've also come across slightly higher numbers based on oil vicosities, but without reference to journal diameters.

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Publications by bearing manufacturers that specify the 996 bearing clearances or bearing clearances in general? The last time I was looking for this, there was little to no information available on this for the M96. That's why I'm asking.

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In general. Haven't been able to find anything specific to the M96 either. Even called LN the other day, and they didn't have a recommendation because of the lack of under/oversized bearings. Basically said "it is what it is." Just trying to be as educated as possible on the matter when shop gets back to me with their measurements, and if any honing is necessary.

Here’s a document from a well known plain bearing manufacturer. Guideline only, not M96 specific, but at least from a credible source. https://www.mahle-aftermarket.com/me...l77-1-205r.pdf

I've heard 0.0025" as a general rule for many years but this is for SBCs or engines like it. Using a general value can lead to problems because it's only a guess. However, since the crank is a used one that will get polished, chances are good a new set of standard bearings will not be tight. BUT this is just how I see it.

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Yeah. I came across that one, and also a more detailed one from Clevite/Mahle that goes into details of bearing failure modes. https://www.mahle-aftermarket.com/me...s-brochure.pdf Also another from King that gets into the detail of eccentricity and crush.

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Yeah. I'm sure the mains will be good to go after the crank polishing. Not as sure on the rod bearing clearance since the rods are new. Should have it all sorted out next week.

The biggest variable is the crank carrier. Before you worry about bearings, check each bearing saddle for concentricity, and consistency. If the main saddles are variably sized, this will be transferred when the bearings are inserted.

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Yep. Got that on the list of the things for the shop to check. Thanks again Jake!

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Don�t task a shop with this. most are going to be sloppy at best unless they are building the engine. You can�t trust what anybody tells you when it comes to precision measurements. The guy doing the measuring might know less than you do, or may be using a Chinese micrometer or bore gage that has no level of precision. You are putting all of your success on the line based on what he tells you. I�m a firm believer that to truly build an engine, you�ve gotta measure it yourself. The fewer amount of hands touch things, the better the end result will be.

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Abso-freeking-lutely. I have a constant war with my management about how more hands doesn't always net a better job. Neither does over-touching by one set. Do it once ,, do it right,, don't fiddle..

I've got a quality dial bore gauge on the way. A little bit of progress over the weekend. Cleaned up some smaller parts.

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Oh, how I love clean parts!

Most of the weekend was spent clearing the slate of house projects to focus on the rebuild. Sunday afternoon I got around to cleaning the case halves including carburetor cleaner to the Nickies. Wish I had LN vapor blast when they did the Nickies after seeing other cases. Also opened up the spot for the IMS Solution oil feed line. Unfortunately I might be in limbo for a bit. Supposed to get the crank and other components back from the machine shop this week, but CT closed non-essential businesses due to the coronavirus. Auto repair is exempt so we'll see when I give them a call in the morning.

You weren't kidding. I'm actually glad I didn't spend more time cleaning my case halves. I don't think I could ever get it as clean as LN did for the amount they charged. Hope your engine shop is staying open and observing social distancing...

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I knew you'd feel that way. The proper cleaning equipment is key. Yes, we are staying open, and continuing on as normal. We have parts in stock for most builds for the next 3 months, and even beyond that. Things are in order, and being prepared to think ahead for 6 months ahead of that, as we received cars earlier than proposed, so we can start their processes ahead of time. This gives us a better chance of getting the proposed completion dates set forth well before COVID19 existed. I have everyone on the admin side working from home, and on the engine building side everyone is spread out between two different facilities, and 3 different buildings. It is entirely possible to work here all day long, and not come into contact with anyone as everyone has their own space, and a lot of it. Deliveries are not even allowed into the building until they have been decontaminated, and delivery people are being treated like aliens. I am working on several engines at the R&D/ Training facility on my own program. All of us have our health, and have stayed at home. The training facility where I am working is across the road from my house, and I have not left my property in over 2 weeks for any reason. Thanks for asking.

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That's great news. I haven't left our property for more than a week. My employer has told us to work from home. I'm fine with that. There are some things that require me to be hands-on at the office - including vehicle testing. It can wait until the worst of this blows over. Whenever that happens to be... I'll post it here - as I have other places - you are providing a great service to us Jake. In so many more ways than just this forum. Most might not know it, but what you are doing with the young people in your area is truly noble.

Talked to the owner of the machine shop this morning, and they're still cranking. Should have everything back by the end of the week. My company is still operating, but with all engineering staff now split into two shifts. Some people are able to work from home, but what I do doesn't really allow for it. So between that and my girlfriend being a nurse, quarantine will probably be inevitable. Everything else needed for the build has already been delivered so it should be pretty easy to guess how I'd be spending the couple weeks at home with no work.

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I'm curious about the block cleaning process. Did you clean your block at all before you shipped it to them? I see on LNE's website that they include a hot jet wash as part of the cylinder install process. Did the block come back a lot cleaner compared to the way you sent it in? After you got it back, it's still cleaning up with the carburetor cleaner? Also, not sure if you've tried citrus cleaner like Oil Eater or P21S Citrus Spray Auto Wash, they work great! I use Oil Eater for most of my cleaning because it's a lot cheaper than P21S.

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LN has the same Ultrasonic cleaner that we have (We have 3) and they also have a vapor blaster. You can scrub parts all day long, and they can look clean. You can put them in the Ultrasonic cleaner and you'll see how clean they were not, when they come out. The surfaces are one thing to clean, BUT my biggest focus is the places you can't see, or reach. This includes inside oil pathways, and small areas in the corners of the case, and crank carrier. Only several thousand watts of ultrasonic sound waves, heat, and detergent can do that, all of which the Ultrasonic cleaners incorporate.

How about dry ice blasting? Its becoming fairly available.. And a lot of them are single guy operations,, might be able to still work with them.. Oh and watch out folks,, a CDC Dr has been doing research on how long the virus lives on various surfaces, turns out cardboard is the WORST greater than 24 hours. Cheers

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I tried that on my 2nd engine, it helps but it's expensive & you still have to pre-clean grease etc. Ultrasonic is the best method I have used.

Engine case got an ultrasonic cleaning yesterday at the same machine shop doing the crank. Definitely more concerned about the cleanliness of the internal passageways than the outside of the case. Picking everything up tomorrow and starting the rebuild this weekend (after verifying measurements)!

Checked the splash valves (oil squirters) yesterday. 1/4" ID tubing works perfect. First used compressed air only, then filled the tubing with water. Valves all opened around 45 psi (not sure of the exact number due air leaks with the setup). Not the most scientific, but everything was consistent. Was able to water the same bush off my deck with each valve (after bumping up the pressure a little).

Magnafluxed, polished, balanced, and cleaned. Mic'd it last night. Polishing took 0.0002-0.0003" off all the journals. Crank was balanced to 1.36g (left) and 1.35g (right). The two drill holes are on the front most counterweight. And here's a link to the machine the shop uses http://www.cwtindustries.com/multi-bal%205000.htm

Lots accomplished over the weekend. Started with putting the new dial bore gauge to use. Main bearing clearances came out at 0.0023+/-0.0002", and connecting rod clearances at 0.0016+/-0.0001". Might seem a little tight, but its my understanding things can run tighter with coated bearings.

Next up was gapping the piston rings. 3D printed the ring squaring tool. Needed to file all of the top and gapless 2nd rings. Total Seal provides three separate warnings in the box to not intermix the gapless rails and oil rails. I'd recommend not mixing them up, because they look identical. Easiest way to differentiate is by weight. Gapless rails weigh 2.7g each, while the oil rails are 2.3g. Rings sets for each cylinder weighed at 28.6+/-0.1g.

Then finalized my component pairings. Reciprocating weight differentials for cylinders 1/4 and 2/5 are exact (at least down to the resolution of my scale), and 0.1g for cylinders 3/6. Rotating weight differentials are with 0.2g for cylinders 1/4, and 0.1g for 2/5 and 3/6. Now that balance should all be taken with a grain of salt. I don't think the measurements of connecting rod ends are accurate down to 0.1g, probably closer to 0.3g. But even as a worst case I think everything is balanced well within a gram. . And finally kicked off the assembly on Sunday!

Checking the axial end play. Attached my dial indicator to the crank carrier with a threaded rod, 12mm OD tube, and a couple 3D printed spacers to tighten everything up between the rod and tube. Results were within Jake's spec. Not as pretty as Jake's fixture, but got the job done 0.0045" on the dial.

Stage 2 complete

Stage 3 complete. And a nice place to stop on Sunday night. Screwed up on my very first circlip, Got it only partially in the groove. I think it came down to not quite enough force and not holding the piston firmly. For all subsequent attempts I had a piece of 3/4" ply wood sitting under the piston, and the circlip seated perfectly each time.

Great thread.

Great thread with lots of info! Good luck on the progress. I'm in NY and we're under full lockdown. Essentials only.

Happy to contribute guys. Trying to hit some of the details that I wasn't able to find from searching the forums.

Knocked out stages 4 and 5...well almost. My 3D printed head spacers (Tool 9613) were short and unable to handle any real torque. Need to lengthen and increase the fill density. I assure you that my girlfriend loves having an engine stand in the "dining room". Yeah, that's not gonna do.

Looking good, really starting to come together.

You and Scott's thread are rocking my quarantine! BTW, I had your exact same bookshelves in college.

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Thanks. Those college shelves have worked out great for a couple years now, but I've got some nice custom floating ones on the summer project list.

Nice progress. Working inside the house makes all the difference.

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Definitely. A large workspace is big help as well.

Currently printing larger and stronger head spacers

And now stage 5 is done. New spacers can actually handle torque! Not bad for about $0.25 in material.

Jumped ahead a bit and continued the cheap tool fabrication. My vario cam actuators are the left hand thread variety. Got the threaded rod and nuts off Amazon for under $9. Only 14k on the wear pads but might as well replace.

RMS tool should be done before bedtime. As I've said before if anyone wants to print their own, I'm happy to share the files.

Nice. It's good to see the progress.

I just used a peanut butter jar lid to make a RMS tool. Drilled 4 holes into it and used bolts to slowly pull the seal into place. You are having too much fun with that printer.

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Hey Yaz - do you have a link, or some specs on those threaded rods? They're lefthand M5, correct? I messed with zip-ties, per Pelican's tutorial. No good.

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Yeah M5. Also tried with the zip ties with no luck. Here are the links: https://www.amazon.com/gp/product/B078H6J4D3/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 https://www.amazon.com/gp/product/B078H6J4D3/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 https://www.amazon.com/gp/product/B077GNH2HN/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 https://www.amazon.com/gp/product/B077GNH2HN/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

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Definitely having fun with the printer and other side projects. Its actually my buddy's, and he rarely uses it. Reasonable to say each part is a two beer job. One for him, one for me.

Stage 6. Rings on pistons 1, 2, and 3.

Prep before inserting the pistons into bank 1. Total Seal recommends using their Quickseat dry lubricant on the cylinder walls (and oil on the rings and skirts). If the cylinders are clean, the powder will turn them a greenish tint. If not, it turns the cylinder a black or silverish color. Nice confirmation that I was thorough on the cleaning. (all cylinders looked like #2 with a little lighting)

Stage 7 done. Incredible how smooth the tapered ring compressor and Jake's instruction make inserting the pistons and connecting rods into Bank 1.

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That ring compression tool is the greatest invention ever, for installing pistons into their bore.

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I had to go through a different supplier - BelMetric. Everything on Amazon is coming from China. Delivery projections anywhere from late April to lat May. Not good enough. So now, I'll have one meter of M5 threaded rod to work with... Might be able to make kits for about $10 each for those looking for their very own.

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I used the quick release front bicycle axle to make my tool - got it for free from a local bike shop. I had gotten a left handed m5 die from eBay, but it turned out that I didn�t need it. My actuators had right hand threads... I wonder who�s idea it was to change them - that guy should get a blanket party! 🤣

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Let me know if it's taking to long to get to you. I've got extra nuts and an extra half of the threaded rod.

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Don't give your money to China.

..

I cut down some box wrenches and put washers on the ends to protect the block , worked ok

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That's almost appropriate to leave as art. The bookshelf and wood floor only add to the look. The smell of carb-clean, though, may change the whole atmosphere...

Brought the A game today boys!!! Kicked things off with Stage 8 (installing the front console and IMS Solution flange). Then prepped the Bank 2 cylinders and installed the guides. So I am using a generic yoke on the engine stand. Definitely makes things tighter. Figured I can make it work since I have to pull the completed short block off the stand when I relocate everything to garage soon.

Hey this thing is starting to look like an engine. Yup brand new front console as the part that Jake warns about broke during teardown (willing to bet it was damaged during a prior replacement of the chain guides).

Piston prep before the dreaded Bank 2 insertion. Planned to put the pistons outside in the sun to help with the wrist pin insertion until I realized that the sunlight was no match for 45 deg F and breezy. Sunlight on the windowsill might have helped, but I actually threw the wrist pins in the freezer for a bit.

If your using an aftermarket kit to do the piston clip install it's worth checking the end slides through the block easily and also fully locates into the side of a piston to allow you to insert the wrist pin, mine was tight , I had to take a bit of the end piece to give clearance, yours might be ok but worth checking before you end up not getting that first clip in ?

The borescope is invaluable. Not the best quality screenshot, but ecstatic the see this result all three times.

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Using the JE set that comes with the LN Nickies. Didn't think to check the lengths, but it fortunately wasn't an issue.

Probably because i havent watched jakes videos or built a porsche motor, but i have no idea what im looking at an those pics

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The big problem is when the circlip gets seated in the counterbore.

Coming in on the home stretch. No relaxing and premature celebrating.

Three for three on the circlips, so no need to pull anything apart or do any fishing. Now I can enjoy that celebratory beer (This was yesterday afternoon Not the 9am or so that I'm finally posting pics).

My version of M96 torque book doesn't list a value for the screw plug for the Bank 2 wrist pin/circlip insertion. Had to go to the Porsche workshop manual which specifies 80 Nm (59 ft-lb).

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Good information. I found the same as you, no listing in the torque book. Just confirmed the same information in the WSM. I will need to crank it down a little tighter now. Have it at only 25 ft-lbs at the moment.

..

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So nothing was specified regarding ring tensions with the Total Seal rings (host of other considerations that I'll get into discussing in the coming weeks). First and second rings were spec'd to 0.018" (0.0045 x bore) and oil rings to a minimum of 0.015. Filed the first and seconds accordingly, but oil expansion ring and rails checked out.

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10# tension is the recommended upper limit on the oil controls.

When I was young building hi-po motorcycles we were always building them with circlip end gaps either open to the top or bottom so as to eliminate acceleration/deceleration flutter of the clip. I’ve never seen it spoken to in the Porsche manuals, but curious of any expert chime-ins.

Buttoning up the oil sump. Holding off on the baffle upgrade until after break-in. There'll be an X51 style one in the future, but undecided on how deep to go. Keeping the original baffle for now. Soda blasted sump plate looks almost as good as the new front console. Hot tip...that 50 ml Loctite tube fits into a standard caulk gun.

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The OEM Porsche (Mahle) pistons have a notch and the circlips have a tang to fit the notch, so no orienting them. Back in the early 80's when I was developing/racing my 2.0 Liter 525hp engine I was concerned about this (12k RPM's) and had a talk with Aries about it (they were the ones doing my custom pistons at the time). They told me they had done the math/metalergy and that it would take over 18k rpm to dislodge my circlips in the worst possible orientation, not to worry about it. I would imagine that all aftermarket circlip makers use a decent margin of safety in this area (hopefully)..

Little overdue for an update... Had been hoping to finish up assembly of the long block this past weekend. Unfortunately sometime middle of last week, I realized I was missing one of the cylinder head locating dowels. Placed that order Thursday night. In the meantime I started prepping some of the remaining sub-assemblies and cleaned components. Camshafts all ready to go.

There was also the matter of relocating the short block to the garage (girlfriend is happier now). I had been debating reusing to old water pump since it only had 15k miles (but 4+ years). Settled on getting a new one from FCP Euro, so I'll be taking advantage of their lifetime guarantee, and replacing it for free every 3 years. Anyone not aware of their policy should definitely look into it.

While the engine was off the stand, I took the opportunity to install the RMS using my printed tool.

And was finally able to proceed last night. Finally! Had been tracking the UPS truck all day. One last look at those oversized intake valves. Final prep on the head gaskets.

So here we stand. Ready to tackle the camshafts. Using ARP head studs. Probably an unnecessary upgrade but found them for a good price back on Black Friday.

That looks familiar. Keep up the good work. Do you have any pictures of the 3D printed rear main seal tool?

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Thanks. Kept the tool simple. Actually used some of the the flywheel bolts as guides while lighting tapping with a rubber mallet until the seal was completely off the protective cover and onto the shaft. And then used those same flywheel bolts and some old valve springs to get it fully seated at the 13mm depth. I'll rig it back up for some pics when the engine is back off the stand.

And Skip delivered right on time. Hope to have the UAOS on this weekend.

Is Jake a whiskey guy? Should probably send a bottle of something down his way for how easy he makes the cam timing...

Still need to put in the plugs and oil pumps, but think I deserve a beer or three. Visually verified intake valve timing on all cylinders before calling it a night.

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That's perfect! Nice work. I used a peanut butter jar lid and drilled 4 holes using the flywheel for the bolt pattern. The lip of the jar lid is a little on the thin side and I had to be careful when pressing on the seal. Your printed tool has a nice wide lip. Again, nice work.

Oil scavenge pumps are on. Added another little upgrade. Found a 997S vibration damper pulley on fleaBay for $110 including tax and shipping. With the accompanying combo bolt and washer/friction disk (which is only 0.005" thick) I'm all in for under $160. Figured if the factory felt the need to add it with the bump to 3.8, I should consider it as well.

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Good idea to add the 3.8 crank pulley - every engine can benefit from this. If someone wants to run an underdrive pulley, RSS does have a harmonic dampening underdrive pulley: https://lnengineering.com/rss-underd...ayman-911.html

Prep for the UAOS install by sealing up the atmosphere ports.

Spent some time researching the vacuum line routing. Auto Atlanta parts diagrams are useful, but they don't include where all those lines terminate. Most complete diagram I found was this one from Wayne Dempesy on the Pelican forums. Think its actually for a 986, and I don't have one side plugged on the three-way tee, but helpful none the less. A- Fuel rail B- Intake rubber sleeve with vacuum port (installed on the right side of throttle body) C- Fuel pressure regulator on fuel rail D- Air injection pump valve E- Electronic vacuum solenoid valve for air injection pump valve F- Vacuum reservoir G- Four-way vacuum tee H- Vacuum check valve (black side points toward the manifold) I- Three-way vacuum tee (one side is plugged) J- Electronic vacuum solenoid valve for resonance flap valve K- Resonance flap valve L- Intake rubber sleeve with vacuum port (installed on left side of throttle body)

Fyi im pretty sure thats a 3.6l diagram. My 3.4 and pics of others show a slightly different set up, i didnt have the 4 way connector on mine. My dealer couldnt pull up an accurate pet drawing for me. Im pretty sure if u were just ordering all new this set would work fine, but that 4 way connector is pricey. I saved a few bucks keeping it original with 2, 3 ways.

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I've actually got a 4-way and 3-way connector with my setup (engine has 2000 build date and the fuel chiller). Think I've got everything accounted for at this point.

Steady progress over the weekend. Most of the time was spent looking at diagrams and pictures, but managed to get a few ancillary items on. Biggest hold up right now is actually the new knock sensors that I thought were going to be delivered a few days ago. Also decided to order a new oil cooler. Old one looks to be in decent shape but its original (so ~114k miles). Minimal effort and $100 to replace it now seems to be a reasonable price for the risk mitigation.

i got the oil cooler kit from fcp euro. The cooler came drop shipped from Worldpac and the o-rings and hose took a few days longer. i suspect they came from a dealer and were repacked. They did have the best pricing that i could find.

Good progress. You're getting close. I see you disconnected the A/C lines. I chose to keep mine intact. The trade off is between refilling the refrigerant versus installing that damn bolt toward the rear of the compressor. I found Bosch knock sensors on Amazon for $35 each. For what it's worth, I took lots of pictures so I can figure out where everything goes. Most are obvious, but some hose and line routing can be questionable.

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Found that FCP Euro has great prices on a lot of stuff. Also like going thru them since they started off local to the area I've been living for the last 9 years. Even now they're just an 1+ down the road from me if I was really in a rush for a part (present circumstances excluded since they're currently not allowing order pickup). I'll put together a post soon detailing where I've been sourcing most parts and what discount codes have been available.

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I actually disconnected the A/C lines after getting that third bolt out. Didn't know my engine had the fuel lines routed thru it until after the fact. As for the knock sensors, found the Bosch ones at FCP Euro for $23 each. The shipping delay was because I added some cheap bolts to my order that weren't actually in stock. Oh well. Weather wasn't going to be conducive to installing the engine this weekend anyway. And there's a good chance I'll be waiting on my state DMV before I can hit the road, so no rush at this point. Definitely wish I had taken more pics of every last bolt and bracket that I removed. Probably have questions for you throughout the week.

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No worries. Bring 'em. Wish I had checked FCP on that. Looking forward to your secret code list. But now that have ordered almost all that I foresee needing, it might not pay off as much as it could...

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Don't think these are that secret, but this is what I've had success with: 10% off at Warehouse 33 by using RENNLIST at checkout. No sales tax. 10% off at FVD Brombacher using Renn10 at checkout. 10% off at Top Gear UK using 911UK. 5% off at GetPorscheParts.com (until May 1st) using RENNLIST320 at checkout. No sales tax, but shipping is overpriced unless the order is $300+. 25% off ($15 or more) at Advanced Auto using RMN25 For PartsGeek orders over $300, use SAVE15 for $15 off. 10% off initial order from Pelican by signing up for newsletter or once per year as PCA member. Also FCP Euro runs promos occasionally (last one was $25 off $250 around the holidays), but nothing consistent. I've cross shopped everything, but in general I've found GetPorscheParts.com (relative to the other dealerships i.e. Suncoast, Sonnen, Sunset...) has the best prices for anything that's a Genuine only part (like my replacement front console, hoses, brackets, misplaced locating piins/dowels, etc). Anything with OEM alternatives, its usually been a toss up between Warehouse 33 and FCP Euro, but FCP's lifetime guarantee tips the scales for any wear items.

So I'm not quite as sorted out on the vacuum system as I thought. Seems the combo of the 3 and 4 way connectors (vs 2 of the 3 ways) leaves me with an extra opening. Everything is routed according to the diagram (thru the appropriate check and change over valves) I posted a couple days ago. But I'm still left with an open end that can be seen near the AOS in the photo below (with the short line and rubber elbow). I don't have any extra vacuum line from the engine tear down (wish I had more pics, but didn't throw anything out). Anyone have any thoughts? Should I just plug it, or swap the 4 way for 3 way? Another thought is routing it to the vacuum line on the 3.8 air box I recently snagged, but I'm guessing that requires some additional modification.

[Image-only post; no author-written text. Original image references:] https://cimg9.ibsrv.net/gimg/rennlist.com-vbulletin/2000x1504/20200421_183858_98f2fe4c26b9c4edc89303dc0f1fdd27909f1dfc.jpg https://cimg9.ibsrv.net/gimg/rennlist.com-vbulletin/2000x1504/20200421_183915_dc093bfe964ed61e22ff07644d1f221c9831dce9.jpg https://cimg8.ibsrv.net/gimg/rennlist.com-vbulletin/2000x1504/20200421_183931_9d888549c3d3cbb3bec510e6c2a0579b1f63b839.jpg

not sure if these help but its how my 3.4l is. The first pic open Y goes to the second pic change over valve, my thin plastic tube broke. One port goes to accumulator, 3rd hose goes foward to 3rd pic. Third pic is the single hose from pic 1 going into the rear of the car. The second port goes to the check valve and the 3rd to the rear most change over valve. Im thinking u have to block off the 4th port or get another 3 way? Where hose 29 and 30 go in this pet drawing seems to be the difference. Maybe someone with a newer motor can look. http://www.autoatlanta.com/porsche-parts/hardparts.php?dir=996-99-05&section=108-05 ​​​​​​ Dont know why the hyperlink wont work or copy but ​​​​​​the pet is from the autoatlanta site edit: looking at your diagram, u need another plenum boot with a port and hook the check valve up differently.

Does this help?

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Thanks. So didn't mean that I'm routed exactly like the diagram, but thru the appropriate valves. I've got the check valve after the 3 way. In the diagram I posted, Wayne has the extra/plugged port on the 3 way (directly connected to the 4 way). In my current setup, the would-be extra/plugged port is on the 4 way. Same functional flow diagram.

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Confirmation for setup vacuum lines to the resonance flap and rubber intake sleeves. Still can't imagine how I could have an open port to those vacuum lines and never gotten any related codes.

Did u have the 4 and 3 way or just the 3 ways originally? If just the 3 ways u would not have had an open port.

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4 way and 3 way originally. Think I just found the evidence I needed...

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me too... one if the ports on the 3 way should be plugged and the check valve should be brought back to the 4 way per that drawing a page up.

Deep dive into my teardown photos... [random typing sounds]...ENHANCE...[more random typing sounds]...ENHANCE...[sound of beer cracking open]...What do we have here?!? Weird angle, but that's too far back to be attached to the vacuum reservoir. Different angle after I pulled the AOS. Looks to be a cap on the end of the rubber elbow.

FWIW, you do know that there is a vacuum schematic on a label, for your particular system, under the rear lid?

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Unfortunately, there isn't even a Mobil 1 sticker under my deck lid. I have found the deck lid vacuum diagram for a 2001 MY (consistent with everything else I've been seeing), but the engine has a 2000 date so I'll do some more digging.

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Oh ok, missing labels huh? You'll figure it out, not too complicated. You should have been working under the hood of the late 70's cars !!!! OMG there were MILES of rubber vacuum lines and vacuum valves and switches. And small engine fires were common place with the 2 inch rubber fuel hose at the carburetor fuel filter. I repaired many an insurance job on these.

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Nightmare material I'm sure. My first (and oldest) car was a 1983.5 Ford Bronco II. Engine had an altitude compensation valve with a propensity to drip gas directly onto the manifold.

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Yep, I was lead troubleshooter for FoMoCo at the time. I loved the Bronco II, I had one myself, it was one of my favorites !! Would go anywhere (4wd), turn around on a two lane road without touching the grass,460miles to the tank of gas, perfect height to get in and out without effort, and with a 4x6 trailer no longer needed a pick-up truck !!

Just to lay the vacuum system discussion to rest... Everything necessary is sorted. Extra outlet on the 4 way connector needs to be plugged (pics seemed to show a cap that fell off sometime/somewhere). Or might swap the 4 way for a 3 way to keep everything tidy. Decisions to be made. One interesting thing that showed up in my searches was that the factory PSE valves are vacuum actuated (link to the install kit from Carnewal is below). Would be worth keeping the 4 way connector in place if I was planning a PSE install down the road, but I'd probably just opt for the Fister or Gundo mod instead. http://www.carnewal.com/products/996...ust-via-Switch

Steady progress. New oil cooler was delivered and installed today. PS reservoir is only there for mock up purposes. Shiny

Nice rebuild, keep it up! I noticed you re-used the idler pulleys. I replaced mine this year for the later plastic 997, much lighter, and it really silent down then 'sewing machine' noise. The original seamed OK(sans one) when I took them off so was not prepared for the noise reduction it gave. I posted a thread the other day about 'root issues of m96 problems', yours seems to fall in to the 'running too hot' seeing the cylinder crack. Probably a good idea to clean out the radiators and check so that the cooling system is functioning properly, especially since you're going bigger. Here is a link to a simple mod to greatly improve cooling: https://rennlist.com/forums/996-foru...-radiator.html

Thanks Nick. Yeah cleaning the radiators and the wheel liner/brake duct mod are on the short list of things to do. Possibly this weekend.

Added the notch to the 3.6L injectors for the 3.4L retaining clips using a rotary tool. Gotta love the "DO NOT MODIFY" on the Bosch box. Old vs new Injectors and fuel rail installed

and you need a wrench and overalls wile wearing a hat to install them and don't do it naked!

More steady progress Saturday. Got the wiring harness routed and most of the sensors and electrical connections completed. Added new ignition coils since they've never been replaced (for at least in the last 13 years/60k miles). Realized the heat shields/trim plates were missing when I did the teardown so I've got new ones coming. As further confirmation towards my theory that the extra vacuum port was intended for a factory PSE, there's an extra connector on the wiring harness that was all wrapped away and tucked away. That connector is the same type used for the change over valve which would be necessary for adding a PSE. Electrical connections mostly wrapped up. New ignition coils to go along with the new injectors. Yeah, there's an extra connector tucked away there. My theory is that it's for a factory PSE that was never installed.

Top side view with the wiring harness routed and fuel lines hooked up to the AC compressor. Definitely should have installed the oil fill tube before all that. Had to undo some of the work to get the one obnoxious bolt since I didn't have any carny folk (i.e. small hands) around.

Quick little observation regarding the intake cross section difference between a 986 and 996 (my gasket set included the intake gaskets for a 986). The 986 gasket fits completely inside a 996 gasket. Didn't do the math, but that makes for a pretty significant difference in area and potential flow rate. 986 gasket fits inside the 996 gasket.

Here's where I left off Saturday evening. Intake manifolds, new hoses, and UAOS are on. Intake manifolds on, and oh what's that in the top left corner... UAOS is on. Still move some of the hose clamps into place, and get some wrap/tape under those zip ties.

Anyone recognize this part? Had it in a bag labeled "AC compressor", but don't see it on any parts diagrams...

It�s the +battery connection in the engine compartment. Inside the small black box.

Just a heads up: The bolt heads on the new coils protrude further out then original, they will touch the heat shields. I just tightened it down anyway, it works but bends the shields slightly.

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I used a couple of 6mm spacers (taken from Shimano XT disc calipers) to space out the heat shields when I put the newer coils on. Worked like a charm.

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$10+ each for those Genuine washers is just criminal. No bike parts laying around so I'll probably some stack some normal washers.

Did I mention I was going big? I know there's a lot a scrutiny about the gains from jumping up to the GT3 throttle body (I've seen damn near every post and video) and the IPD plenum (snagging one from FVD for 20% off definitely swayed my internal argument). Figured it would be warranted in my case due to head work (including oversized intake valves) done by Hoffman and the increased displacement. I'm holding onto the stock components so there might be a dyno comparison down the road. IPD plenum and UAOS connections from the backside 74mm vs 82mm throttle bodies

And there she is. Still waiting on a couple coolant hoses and those trim plates, but the next big steps are getting it off the stand and attached to a tranny. Install is on for next weekend (weather permitting...knock on wood).

It'll be worth it - guaranteed ! Also smart to do it with the engine out - it was a pita working from the back of the car with the motor in place...

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Nice! Hope all goes well, brother. We've been on a similar road for a while. Hopefully we'll both reach our desired destination.

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I'm loving the great pictures !!! Can I have your permission to use these in my upcoming UAOS Adds?

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Of course. You're welcome to use any of these pics. Great job on the integration. Could easily pass as a factory design.

Awesome job, well done! Don't forget to take out that crank locking pin.

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Thanks !! Yes that was one of my main design targets, to look as though it was a Factory design and not look "aftermarket" !!

Just wanted to say how appreciative I am of all the comments and well wishes throughout the whole process. Could only have hoped for such a response when starting this thread, and the Rennlist community delivered.

Diagnostic prep work. So I decided on buying a Foxwell over Durametric because I don't own a Windows laptop, yet I still needed to use my buddy's Windows laptop to install the updates and Porsche module... Porsche module installed Wait why am I getting codes...oh yeah...

How does the fox well compare to the durametric? Function and price wise, where's best to buy from?

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Its my understanding that it compares pretty well with one exception being it can't check over-revs. Yesterday was the first I've played around with it. Its a bit cheaper than the Durametric (and doesn't require a laptop other than for updates and loading the make specific software). Its available thru Amazon, but I found it a little cheaper direct (sales come and go pretty regularly): http://www.foxwelltool.com/wholesale...YaArX4EALw_wcB

Thanks Yaz 😊

Last parts order (knock on wood) showed up Wednesday. Swapped out the 4 way vacuum connector for a 3 way. Installed the underside coolant tubes. Pulled off the Bank 1 intake manifold to add a plastic support bracket (went surprisingly quick). Installed ignition coil cover plates using some stainless hardware (cut some threaded rod to ~34mm lengths and used nuts as spacers) instead of the Genuine setup. Also got on the muffler supports and headers. Pulled off the Bank 1 intake manifold to install the breather tube and wiring harness bracket that bolts onto intake #2. Yeah, that should be replaced. Cover plates, muffler supports, and headers on.

Top Gear UK 200 cell cats are on. Can't beat that price (10% off using 911UK). Literally poured coolant out of the old Bank 1 cat during the teardown so figured replacement was necessary. Undecided on the long term exhaust setup.

Lookin' good

Nice! Looks like you'll be putting it back in soon.

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​​​​​The plan is to do the install Saturday. Forecast is sunny with a high of 68 around here.

This is the time to modify the mufflers to get a nicer sound out of them. Good progress by the way.

Sounds like you and Scott might both be installing soon. Y'all gotta have a race you know. On your mark, get set...

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It my not be a factor for you, but I had to use extenders for the O2 sensors. Also the post-cat bank 2 wire was too short for reaching the bank 2 post-cat bung on my TG 200s.

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Thanks. Probably do the Fister mod soon. Wanted to get back on the road before any exhaust mods (aside from the likely coolant fouled cats).

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Did you need the extenders because of a CEL, or just wire length?

Ready for a weekend install! A cheap aircooled Porsche/VW flywheel lock worked great with a quick angle grinder modification. Dorman HELP! (quite the product name) 14503 is the perfect clutch alignment tool (and under $5). Ready to go for the install Cheap aircooled VW/Porsche flywheel locking tool with a little modification Dorman HELP! 14503

Looking good. How did you get the engine off the stand? I'm trying to figure out how to use my cherry picker to lift it off the stand and place it on the table. Haven't seen any obvious chain attachment points to work from.

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Very carefully! A cherry picked would have been nice to have, but (with not having one) I'm not sure about attachment points. I had it really well balanced on the jack with a cross beam attached with a buddy helping out and extra stands around for additional support. Also put a 2x4 across a couple stands under the front of the engine just in case. Once the engine stand was out of the way I moved the jack stands under the engine mounting points and added the wood blocks under the rear of the engine.

I guessing the best way with a cherry picker would be to yoke it with a soft strap. Keep it up guys. Maybe all 3 of us will have a running motor by the end of the weekend.

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Ok - maybe I can work out supporting it from underneath. This should be as epic as the building of the pyramids.

Anyone want 10 gallons of 1yr+ old 93 octane? Not quite done, but a solid Saturday all around. Started with draining the fuel tank and replacing the fuel filter. Ended up with the entire drive train (except for the airbox) in and torqued down (including all hoses and electrical connections). Some remaining work to do on the underside, mufflers, and bumper. Getting close...

Awesome! So very close!

I was getting codes for post-cat below efficiency, or some twaddle like that. Wouldn�t test �ready� w/o the extenders.

Yaz - What method did you use to pump out the fuel? That's on my list too.

He jumped the relay. There us a post a little lower.

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Got more details on this? Like a photo showing which relay and where to jumper? I'm sure I can research this and figure it out - but I've got a header to swap out...

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Yeah jumped the relay. It the only pink one under the drivers side. Pin 30 to 87. Just be aware the diagram on the fuse isn't the actual pin locations, but the pin numbers are stamped on the backside. I was also replacing the fuel filter at the time, so drained from there into a 5 gallon bucket. Had some plastic kegerator tubing (not sure of the ID) running from the fuel line into the bucket. Fuel pump relay is the only pink one. Jumping pins 30 and 87.

Thanks, Yaz. That's a big help.

Soooo close. Late start Sunday because my pup Ziggy needed a decent hike...and swim...and shower. Got the car all back together (except for the airbox) and back on the ground, then started on the fluids. Should have added the distilled water while the car was still in the air. Had one leak that was fixed by tightening a hose clamp. Might have another leak at the rear bottom of the engine. Or it could (hopefully) just be water that was running from the first leak along the underside coolant pipe. I'll have a better idea this afternoon. Going to need all weather mats before his next ride. Back on the ground...for now.

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Another good day...the potential coolant hose leak appears to be a non-issue for now. Got back under the car this afternoon for a closer look, and nothing worrisome. Then it was time to get the airbox installed. Picked up a 3.8L off eBay for about $200. Figured it would be worth it for the cosmetics alone. I've closely followed all the threads about what fits... 3.8 snorkel requires SAI relocation... 3.4 snorkel fits the 3.8 box and doesn't require relocation. Was leaning toward using my old snorkel until I saw the cross section off the inlets. 3.4 inlet is roughly 3-3/8" x 2-1/2" (~7.9 sq in) versus the 3.8 inlet being roughly 4-1/2" x 3" (~13.5 sq in). That's about a 70% difference in area. So I'm going with the 3.8 snorkel. Removed one bolt on the SAI for now, and might get the EVOMS relocation bracket if I notice any vibration. There's your 70% difference on the inlet Done. The plan is to fire her up tomorrow afternoon.

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That looks great!!

Started off with a final check of fluids and tire pressure, torqued lug nuts, and reset the DME. Battery wasn't up for the whole starting procedure (picking up a new AGM one tomorrow) so I procured the help of jumper cables and my 4Runner. Then went thru the starting procedure described by LN (and probably a few other threads on the forum). I was able to build up the oil pressure and get the engine started!!! Then my girlfriend pointed out a leak. Quickly realized I had a pretty significant power steering fluid leak from one of the hose couplings. So I'll be sorting that out (and doing some extensive cleanup) over the next couple days. Tonight's research as me thinking I'm missing an o-ring or it just wasn't completely seated. Should have given those high pressure fittings more attention.

Well, you know it starts!

Power steering coupler was a quick fix. Cleaned things up. Dropped in the new AGM battery (used RMN25 for 25% off at Advanced Auto). Car fired right up again. Jumped back into the initial start up procedure described by LN. No leaks. Even had time for a drive before tonight's storm rolled in... HOLY ****!!! This engine is a beast. My heart is still racing from the first drive. Can't stop laughing to myself (probably sounds more like the giggling of a school girl). Hands are shaking a bit. I realize this is some mix of the raw power of the engine, having not driven a Porsche in over a year, and the sense of accomplishment of my first engine build. I'm not able to differentiate what is what, but for now I really don't care.

Congrats! But no video?

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Congrats! Here’s to a long life

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I was actually setup for video of the initial startup on Cinco de Mayo prior to the battery and power steering leak. Today had the feeling that the car deserved my undivided attention. I'll put something together soon.

Welp. Got a problem... Car felt like it was running great with with solid fuel trims. Noticed yesterday the cam deviations seemed off. First time I checked they were around -4� and --7.5� on banks 1 and 2 respectively. Creeped further to about -5� and -8.5� this morning. Should have investigated more before driving this morning... Started running rough on the highway and threw a CEL. Codes P0300, P0301, and P0304. So misfires on cylinders 1 and 4. Any thoughts? Crank position sensor (it was replaced during the rebuild)?

Did you properly torque the bolts on the cam drive sprockets? What were your deviations when the engine was running smoothly? It sounds like those sprockets May have slipped (I don�t remember what the torque on those bolts are off hand, but I know they�re not very high... 16-18 ft lbs ? Maybe 20?...). The plus side is, I�m pretty sure you can do these with the engine in... bank 1 more difficult than bank 2, since they�re behind the oil pumps... Good luck

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Cam sprockets were torqued to the spec in the Knowledge Gruppe book (which is actually only 10.5 ft-lbs). Engine felt smooth up until a few seconds before the CEL. The fact the deviations drifted by the same amount is what makes me think it's related to crank position.

Well done ?

A thumbs up comes out as a question mark lol unintended , genuinely well done, it takes some guts to take on a full rebuild, lots of research time and money, and the nagging thought in the back of your mind, at the turn of a key if I've messed just one thing up it could all go up in smoke, I could hardly bring myself to turn my key when I was on my first start , well done , think I'm going big cylinders next once I've filled the piggy bank !

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12.9 fastener used, not the 10.9? Did you happen to use loctite on the fasteners?

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10.9 fasteners. No loctite. Might have just picked the wrong number out of the book this morning. Took a quick look before scrambling off to work. ​​​​​​Guessing the cam sprockets are a good place to start regardless.

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Last I checked, the cam sprocket requires the 12.9 bolts, not the 10.9. I'm sure you haven't hurt anything, but I would not drive the car any further until the cam timing is corrected. The reason I asked about the loctite is we've seen the bolts actually come loose if loctite is used.

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I just checked mine. It has 10.9 bolts, too.

Looking at the pet, depending on what cam sprocket is used, you have two bolt options: #29 90037816201 Hexagon-Head Bolt M 6 X 15 For 996 105 178 52 x 8 #29 90038504101 Hexagon-Head Bolt M 6 X 12 For 996 105 178 53 x 8 I do know these bolts are specific to the camshaft sprockets and Jake's book shows different torque specs for M96.01/02/04 vs M96.03, so maybe the earlier engine and fastener is the 12.9 I am thinking of. I don't have any of these fasteners here to double check the grade unfortunately.

If there was any oil between the sprocket and the cam flange, that could also cause it to hydraulic and not actually be torqued down properly. That's the more likely scenario.

According to the fastener spec book from TKG, the .03 lists the bolt as grade 10.9 and torque spec as 10.5 ft-lb. The .01,.02 and .04 don't list a grade but do list the same torque value (10.5).

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That was a big issue for us in the diesel field back in the day of injection pump, tech would clean the cone contact between the injection pump shaft and pump gear with brake cleaner which left a petroleum films on the contact part of the two which don't use a key, so first run on the dyno as the engine warmed up, they would lose pump timing as the injection shaft would turn on the pump gear. solution was to clean the contact area with Electronic contact cleaner and no issues after that.

Thanks for all the input so far. Towed the car to the nearby indy this morning out of convenience and curiosity of their opinion (no charge). They said I wasn't getting oil pressure, so not sure how that fits into the equation. Anyway I was going to tow it back home this afternoon, but apparently (according to the towing company) AAA has a policy that they won't tow a vehicle from a shop to a residence so I'd have to pay the towing company's normal rates. At $105 just to put it on the truck (and around $175 total for the ~10 miles home), told them to get lost. Car does start but I'll play it safe and just push it in front of the house next door to the shop in the morning and take my free tow.

The only thing I can think of if both banks seem relative and like you say it's related to cam position, I hope not but could it be the ims gear slipping on the shaft ? Did you have it pinned during the build, I really hope it's not this as it would majorly suck for you as it's a full strip down to fix , fingers crossed it's something simple !

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Thought about that, but yes the shaft was pinned. Plan for the weekend is to smoke some ribs, drink some beers, and relax on Saturday with a couple buddies. Then dive back into the engine on Sunday with a clear mind.

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Yes a step back is worth it's weight in gold , you'll get her right , your build was absolutely A1 all the way, maybe if the torque isn't quite enough both cam banks are slipping equally if you know what I mean , maybe if you could get one of the scavenge pumps off and take a look , or maybe put her in TDC and pop the cam plugs out and see how the timing tool looks , if it's out maybe just retime the banks , torque the sprockets up a bit more or use loctite and your all good hopefully, but for now enjoy the beer and ribs mmmmmm ribs !!

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How did they determine you have no oil pressure?

photo183.jpg Found this in my manual , had a read , it says to tension the chains with the special tool or chain tensioner then use the timing tool to set the timing , says to torque the bolts loosely to 10nm whilst carrying out the timing then a final torque of 14nm at the end , what torque did you finish on ? also bolt is M6x15 10.9

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Pressure gauge and the warning light. Oil level is normal and the sending unit is new. The engine does run, but sounds terrible. Oddly enough it's not throwing any codes after I cleared the prior misfire codes.

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It may just take a while to throw a code. I wouldn't keep starting it, until you go through the cam timing procedure again and make sure those bolts are all torqued properly. I think the "hydraulic oil layer" theory is plausible enough to pull the bank 2 oil pump/cam plugs and check that sprocket. If that one has slipped, there's probably a good chance the other has as well. It seems like a slim possibility, but I think the cam deviations are the best indicator you have to go with... Good Luck!

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This is what you need to concentrate first and worry about the timing later. Do you have any oil pressure at all or it's sitting on 0 regardless of the rpm?

Do you remember if you put the hex key drive in the oil pump? No oil pressure sounds bad. Something is missing. Oil pickup tube?

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I definitely had oil pressure during the first couple days, but I wasn't watching it the morning the codes were thrown.

I was thinking sheared oil pump hex drive key maybe worth checking it if no oil pressure, dont keep running it, if it sounds bad, by bad do you mean rattly like no oil pressure or just bad like misfiring rough running ?? The only thing I can think of that would suddenly lose oil pressure is the hex drive , especially if it sounds rattly This might be an engine back out and check sinario !

Yaz, did you install an upgraded oil pump hex drive? I have tested the factory hex drive and it fails (literally shatters) at 54 ftlbs torque. I have used MAC 8mm hex Allen Wrenches to make upgraded drives that test to 153 ftlbs torque. (just cut to length 1.99"). Normally its not an issue, but you having a brand new oil pump, it could be a little "tight".. LN also sells an upgraded oil pump drive hex. You can get to the oil pump drive very easily, just remove the cats and the small oil pump cover and pull out the gears, the drive is right there. If you didn't drive it long after pressure loss, you're probably ok, with brand new oil and all. (fingers crossed)

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Thought about the hex drive but I did install the upgraded chromoly one from LN. It sounds bad like misfiring. Oil light actually didn't come on until after the misfire codes.

Drained the oil and going to drop the sump plate shortly. Going to check the hex drive and bypass valve spring at some point. Magnetic drain plug is picking up a good amount of material. Not sure if that's inline with what's to be expected of a new engine. Greyish color of the oil had me concerned at first, but I'm reading that its from the ARP lube. Magnetic drain plug doing its job. Grey color had me concerned until I read its from the ARP lube.

That looks like a problem. Now trying to figure out what I'm looking at...

Ouch!

I don't know what the solution is, but I'm so very sorry to see these posts. Gut wrenching. Hoping (as I'm sure we all are) - that it isn't something major.

Holy Crap! Is any of that debris on the paper towel magnetic? I'm not sure what is would be from, even if it is. I hope there's a simple correction, but that's a kick in the nuts.

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I've taken more than my share of kicks, pucks, and sticks to the nuts, and I can assure you this is a different feeling... Most of it is magnetic except for the large chunk and long, thin piece. Spent the last couple hours looking at parts diagrams and my install pics, and still don't have a clue.

Damn. Sorry to hear of your issues Yaz. I was rooting for you. Hope it’s nothing too serious.

I'm willing to bet my oil pressure issue is due that debris going thru the pump. Fortunately I have the gears from my old pump/front console that had the broken flange.

One of my first steps would be to scope the cylinders you had the misfire in. Especially #4. Keep your stick on the ice.

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Pretty much decided that I'm pulling the engine and putting it back on the stand. Cam covers are coming off, and I'll scope the cylinders before deciding if pulling the heads is necessary. Went with the ARP head studs, so at least I don't need to worry about those being TTY.

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Yeah - dropping the engine and getting a good look makes the most sense.

Wow major bummer. Nothing more to say at this point - hoping for the best possible outcome...

$hit! Those pieces look a lot like crank and/or rod bearings to me.

Sad. Sorry for you. That is a real gut punch. Something terrible is definitely going on.

Hey yaz, just keep going I'm sure you'll get to the bottom of the problem, seems strange something like this , your build was looking amazing , meticulous and clean , I can't imagine how you must feel , like you say though at least you got arp bolts so even if you strip it down maybe a few gaskets and seals to get it back together! I'm sorry to say the copper coloured debris does look like main/big end bearing , I really hope not, maybe Jake will chime in . Good luck buddy keep fighting the good fight!

Thanks for the suggestions. Spent a good amount of time tracing my steps. I'd say the prevailing theory is there was a blocked oil passageway to one of the bearings. Possibly some debris leftover from the work done on the crank (magnaflux, polish, balance, and clean). Unfortunately, the one missed step that I can identify is I never verified the passageways were clear.

Your theory of a clogged crank oil passageway seems logical to me. A failed rod bearing (most likely in my experience) would explain the loss of oil pressure and the debris. It's likely the debris have affected the other bearings and engine components. I would be planning on a tear down to the crank. My hope would be that the cylinders are not scored.

I just wanted to add some sympathy to your position Yaz, I'm only a recent owner and was following your build with great interest since my car was a comparatively cheap high miler and I won't be surprised if I have to do something similar before too long. I really liked the way you worked, in all the photos I thought this guy is doing it how I would do it. For you to encounter problems is a sobering thought to those of us who look on thinking they will need to do the same at some stage. I thought I'd share that the first proper engine rebuild I did was in the mid 90's on my quite unusual Italian motorcycle, with parts that were hard to source at the time and very expensive for me relative to my income then. I spent a year or so with many problems encountered and overcome along the way, and when I fired it up it ran for about half and hour and then nipped up an exhaust valve in the guide and started making terrible noises. I was pretty devastated. I pulled it all down again and did it again, I was lucky and there wasn't too much damage, just a bent valve and damaged guide really, but I had to do the damn head all over again anyhow. It was 25 years ago and I still remember the feeling first of elation when it fired up, then dismay when it all went south. So I thought I'd just send some positive vibes. After overcoming the issue I rode the wheels off that bike and it's still going now, with that same engine build, and I still love it... in no small part due to the trials and tribulations we went through together during that engine build. All the best Uber (Steve)

Yaz, we look forward to your discoveries and pictorial of the teardown. hopefully it’s a quick fix and not too much money. .

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Everyone following this thread will be getting their (my) monies worth. Just hope I'm finally on the upward slope of the plot below:

At least you have maintained some sense of humor! So hoping there is not collateral damage found....fingers crossed. Amazing build, hoping for the best.

Yazz I think once you accept what's happened which you seem to have pretty well!! You can move forward with new goals! Just be prepared , I'm guessing your heads and cases will be ok, I'm thinking it's chewed up the main bearings or rod bearings , you know the crank will probably be toast ! I think you will need so source a good used crank as they are case hardened and can't be re ground (ask me how I know!) I'm in the uk but know some good dismantlers here so I can possibly help if needed , good luck and keep posting the updates , you will get there ok

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Crank condition will be the big variable. Going to have the local shop that did the work check it out. That'll be an interesting conversation. Worst case I'll be getting a crank from LN, but if anyone has a source for a quality (non-spun bearing and polished for show eBay special) crank it would much appreciated.

I believe you would need the matching crank carrier as well. I seem to recall line boring these carriers is not a done thing

Definitely don't want to make this a habit, but pulled the engine in under 5 hours this time. Never recharged the A/C so I did save some time by not dealing with that.

Taking things apart, is always a lot easier than putting them back together. Best of luck. You know, we're pulling for you. After about 20, or so, you might get the message.. You Tube

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If the Boxter 2.5L crank is the same then I may have a lead for you. Let me know when you find out and I will send you his contact info.

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The 2.5L has a 75mm stroke. The 2.7L, 3.2L, and 3.4L have a 78mm stroke. The 3.6L has an 82.8mm stroke. That doesn’t mean that all of the 2.7, 3.2, and 3.4L cranks are interchangeable, but the 2.5L wouldn’t work.

I'm sure you could use the same carrier with new main bearings , I don't think the carrier is matched to the crank , the two halves of the carrier will be matched as they will have been line bored together but I can't see how that could then be matched to a crank ?

Fingers crossed the crank may come out ok, bearing material is purposely made soft to protect the crank , if it didn't run long when the pressure dropped you might get away with it! I know what you mean about dodgy cranks on eBay I've seen a few with a knackers journal or two, I've got one with one knackered rod journal from my old engine , so frustrating how they can't be re worked!

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Reading this thread is better than a good novel. Sorry to read about the new problem and hope it works out to not be too expensive. I'll be sure to re-read this thread when I have to do my engine!

Wow..having just rebuild M97 in my cayman, I can't imagine the feeling. Now you gotta find out what happened. Really sorry but can happen even when somebody else re-builds it. I knew of a guy whose new motor went during the first track session. Hopefully things can be salvaged but I think I see parts of rings in the pan and lots of gold.

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I'm too young to even know who that is!!!

That's OK. You just run along, you little scamp... Watch The Westerner . It's a classic movie. You can find anything on the interwebz... https://www.dailymotion.com/video/x2be36q

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It's been a roller coaster. If I'd only stayed around Hollywood, this could be script material. Engine is currently on the stand and almost down the the long block. Turns rather smoothly by hand. Scoped all the cylinders. Some (what I would call) streaking (not scoring) that's consistent on all cylinders, and I'm guessing is normal for 69 miles into a break-in. Planning to finish the teardown this weekend, and all indications still point to a spun bearing. Haven't seen many cylinder scopes from under 100 miles so hard to call this typical.

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I think I read LN saying streaking is ok as it wears in and not to freak out. Tearing this thing down should be couple hours now. What a bummer. Drum roll. Would spun bearing be due to improper tolerance?

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Tolerances on the bearings and journals were all within two ten-thousandths. Clearances might have been tight side, but I had an engine shop check them (also measured myself), and they said I'd be good. Its a definitely possibility, but I'd bet its a blocked oil passageway due to either leftover debris from the crank work or excess sealant somewhere. Should have a better idea once I get to the crank this weekend.

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I meant clearances - what were they anyways? 2-3/1000s? Did you use bore gauge for bearings? Good luck with the rest of tear down. Take your time.

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Between 0.002" and 0.003" is normal clearance in most engines by most manufacturers for the last several decades. Even if let's say a bearing a tight but gets normal oil pressure, it will clearance itself and not spin. Spinning of a bearing is usually the result of no or very little pressure and severe lack of lubrication or a very high load and not enough oil (high rpm with low oil pressure). The OP said he didn't rev the engine so the problem, if it turns out to be a spun bearing, is more likely what he thinks it it and something prevented a bearing from getting oil.

Split the case. Rod bearing on cylinder #6 is toast. Now it's time to find any collateral damage (piston coating is the obvious one) and the the root cause.

Oh man... So discouraging... Hopefully there's not too much collateral damage and you're able to resurrect the engine in a reasonable amount of time and for a reasonable amount of $$... Good luck!

Faaaaaack!

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Or care!

Ooof. Hopefully most things can be reused. Crazy skirt wear...on #4 a well. Can't imagine that being normal. Let's see the crank...but if that bearing is gone it's probably bad.

Hope things can be salvaged and replaced at a reasonable cost!

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Oh man...When you say root cause, is it something you did during the rebuild, or a part that was re-used? Feel for you man...

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Still thinking the root is a blocked passageway from residual debris or excess sealant. I'll have a better idea after the weekend.

Got to the bearing 🤔

Crap Crap Crap

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Yeah, I was hoping to see a little more material there. Maybe even two halves. Probably time for a beer or six...

Mains 6 and 7 were on their way out. Figuring the crank is done at this point, but I'll still check passageways.

Hey Yazz Ouch ! Looks like oil starvation somehow, some heat there to destroy that bearing like that, I think the cranks has its day ! I would say if your lucky and the bores have survived, your looking at a crank , pistons and bearings, plus a full clean , interested to see what your route cause might be? Hope you can get it right , keep going on

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Definitely crank and bearings, probably one rod. Pistons look good except for the skirt coating (curious what LN recommends on that). Bores and rings all look good too. Still trying to figure out why that journal wasn't getting oil.

Man, so sorry for the gut punch. I had my fingers crossed for something less serious.

Looks familiar .There is an answer....

Oil pump hex drive normal ?

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Hex drive is good.

WOW, that bearing looks bad. How long did the engine run before you realized there was a problem? I have some used spare stock rods for a 3.4L if you need them. PM sent.

Oops, I just noticed you don't have stock rods.

Pretty gnarly photos, my sympathies. I hope you find the cause. All the best

Hey Yazz You might be able to get the skirts re coated, my pistons have the sprayed iron coating ( re used standard due to cost) but I had them don't with a Teflon coating , just a couple of thou thickness, a company in Uk called Camcoat , they do stuff for f1 and MotoGP but there will be companies over your way, maybe find out exactly what the coating is and send them to a specialist, just get them re done , if the metal underneath looks good , maybe measure them for wear and allow for the coating thickness . Also maybe check the carrier for blockage , the crank is the first things to get oil so that should narrow it down, the main journals get the pressure then it runs through the crank to the big ends , just bad luck mate , I'll see if anyone has a crank over this side of the pond, keep going!

Man oh man! I hope you at least find the reason what caused all this.

I wonder what caused what. I see a chip on #7 main, which if I'm not mistaken feeds #6 rod bearing. #6 main looks deformed from heat that could have been from #6 rod bearing. Or #6 rod bearing failed first and caused main bearing around it to overheat. I find it hard to believe that debris from polishing would block anything. We are taking microns for stuff they take off. But who knows, something else could have gotten into the passage.

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Engine was running for a few seconds before I shut it down and coasted off the highway. The indy that I initially towed it to started it up before I got there, and not sure how long he had it running.

Crank and carrier passageways are clear. Maybe any debris that was there could have shed after the bearing disintegrated. Oil cooler was new so can't imagine that factoring in. Splash valve on that main seems to be functioning properly.

..

So sorry to hear, Yaz. You seemed very thorough in your assessment and build, so I'm shocked to see this. Just throwing some ideas out there. I haven't read through your thread yet, so sorry if I mention something already listed. Is all the damage confined to the bottom end? Is it the original oil pickup tube?

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Fortunately the damage does look to be pretty localized: crank, main bearings 6 and 7, the one connecting rod, some melted plastic on the oil baffle plate, and piston skirt coatings. There's some metal flake worn into the chain guides, so I'll replace those again. Oil pickup tube was original, but I did completely disassemble and ultrasonic clean that and the sump air separator tubes. Also was somewhat surprised to find zero debris in any of the oil pumps.

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Are you able to re-use the block I hope? Just re-honing? Do heads need to be decked again? Maybe I missed it but how many miles/hours did you run it for? Do you think there was an issue from the start? I saw you drove it and it appeared to work well. Did you drive it hard our of the box?

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Why would you recommend decking the heads?

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This needs to be done during the rebuild as head surface is not perfectly flat. I'm not sure if they get any imperfections after installation and part of break-in or that's only with longer term use.

Nc993. Cylinder heads were redone professionally during engine rebuild.Have only 69 road miles on them,engine not overheated(coolant temperature wise).

Sorry Nyc993

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Yea I would think they are fine as well, but I was curious if there is a definitive answer.

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Who told you this? Heads only warp if they overheat. Rebuilders do this because they don't want to bother checking and it's easier just to skim it but this doesn't mean they need it. The correct way is to check the head for straightness and ONLY machine it if there is a problem it it. Corrosion can also be a reason to re surface a head but that again is not because the head was warped. Re surfacing a head for no reason eliminates the ability to do this when in the future the head really needs it done.

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There IS an definitive answer. You can easily get it by checking the head. There are ways to measure this and that'show it has been done since they invented the internal combustion engine. Don't just blindly start resurfacing it.

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chillax, I asked the question didn't I? I didn't say one has to in this case.

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At least in my case, I didn't need to even measure, it was pretty obvious to a naked eye plus head gasket material stuck. Maybe we use different terminology. I mean getting the surface super smooth and leveled.

A Couple of observations that might be of interest. Firstly it is aged and temperature stress relieving that causes the heads to distort when they are removed from the block. Stresses are trapped inside castings because the outside of any section always cools before the inside and as the outside stops shrinking the inside continues as it cools and forms inner stresses that are contained. When the parts are machined the stresses sometimes come out (and final cuts reveal this), but then a process takes place in which continual heating and cooling gradually releases those stresses but do no harm because the parts are Bolton together. The blocks suffer from this to especially because they do not bolt together across the joint face but only at the outside (the inside being where the crank cassette fits). When they have been dismantled and the stresses finally allow the parts to find their natural free shape - the distortion is not a curve that will be pulled out by tightening it all down again but humps and bumps - so to get back to perfectly flat surfaces both need machining or there is a risk that the three part steel head gasket might not perfectly seal. That is a risk home builders might decide to take but a business rebuilder cannot afford the consequences of problems so will not take that risk. It is not because they cannot be bothered to measure the surfaces (your being too cynical here)! Regarding the crank, Sometimes they also distort on strip down and run around 0.1mm out of true when free on a bench. The rear overhang results in the heavy flywheel kicking sideways when the clutch is engaged (especially om aggressive change down) and that wears the rear main bearing prematurely. The oil pressure being fed to the rear main then passes up to the big end via a hole in the crank. The big end is under more stress than the main bearing so as the rear main wears it drops the oil pressure to both the main and the big end (which suffers most) and can fail. We fixed this by machining the crankcases and fitting a rear bearing to support the crank but it is not easy because a combination of tooling and machining tolerances and the fact that the crank carrier is in a cassette results in the crank sometimes being up to 0.2mm out of alignment with the Rear Main Seal hole (the reason why the engines initially had RMS leaks until they replaced the seal with one that will distort its centre to the cassettes alignment) so the whole crankcase has to assembled with the carrier and then clocked true before the new hole can be aligned. We have an internal report on this whole subject that I will be happy to send to you (Yaz) if you E-mail [email removed] . However the big ends remain a weak area partly because the centre distances between the cylinders was not increased as the capacities were and that distance dictates the resulting thicknesses of the crank pin width, and the web widths - so if you try and make one wider you have to make the other narrower (and so as capacities increase and with it loads - the big ends remained the same width). A weakest part of the crank is the oval eye shaped section where the crank pin diameter joins the web (which frequently fatigues and beaks) and a hole in the end of the crankshaft was changed during different production models allowing the end of the crank to flex a little and reduce passing the full bending forces directly to that weak area - but the downside was that it also enabled the crank to flex more at the end and wear the rear main bearing prematurely. Sometimes the flex passes along the crank to the next inner main bearing and number 5 big end wearing first. Being a wet sump doesn't help as the big ends are the most vulnerable to low oil pressure that can result in braking and cornering. Worn dual mass flywheels and clutch plates all influence the amount of kick to the rear of the crank on changing down (or in the case of a Tip - worn torque converters). Lightweight flywheels can exacerbate the problem because they have lower inertia which enables them to kick further sideways on clutch engagement. As well as our modification to fit a support end bearing we also are developing other products to improve crank bearing life - but unfortunately we always test all our products for many miles before releasing them to retail and there is some considerable length of testing time left before we will be able to assess their value.. Baz (Barry Hart technical director Hartech Automotive) www.hartech.org Machining the RMS in line with the crank carrier The New support bearing behind the re-positioned RMS The typical eye shaped weak area of the crank

Hopefully this picture is the right way up Baz

This picture taken from the report demonstrates the small crank journal, long overhang and weak spot. Baz

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So help me understand then. How come much lighter LWFW that is balanced together with the crank is such a bad idea compared to a heavy DMF most of which are failed at this point. Also doesn't transmission shaft provide support?

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Sorry dont want to clutter yaz's thread but..... Not sure in the first part but i suspect it has to do with harmonics and dampaning when engauging the clutch. On the second question its the opposite. The cank/pilot support the input shaft of the trans as the clutch engauges.

The lightbulb in my head is now much brighter on this subject of the rearmost mains,in regards to the DMF...That a lot of mass supported on just one side,and if it has aged out.......oh boy! Service intervals on DMF😳

OK I understand that you have doubts. My internal report is actually 3 times the length of the short one I have offered to Yaz and is the result of years of painful research and testing - but then you guys think you can fault it without even referring to it - fair enough. The first point is that you are right that the gearbox shaft fits inside a bearing. It is a long protruding shaft, weak enough to bend - BUT what does it fit into - "the flywheel" and what does the flywheel fit to - "the crankshaft" - so if the crankshaft flexes off centre - so does the flywheel and the gearbox shaft - RIGHT OR WRONG? you cannot argue that the connection of the shaft to the part I claim bends doesn't bend because it is connected to it (unless your mission is just to disrespect intelligent research and a willingness to try and help and share). Now I will try and post some more pictures which will show a cassette with a crank in where the last main bearing is worn (and the shell measures 0.5mm thinner than a new one), yet the next one along is not worn at all. How did the last main bearing journal wear the shell so much if it did not move off centre and how did it do that without bending if the next main bearing is perfectly OK? ANSWERS PLEASE! We have also seen evidence of the flywheel touching the inside of the bell housing in other failed crankshafts and you can measure the deflection needed to manage that. This is the problem I (and other capable specialists) suffer. We have rebuilt almost one engine/day for 10 years, seen countless failures (road and racing cars), are qualified and experienced engineers and have fantastic facilities. That doesn't automatically make us right but it is far more likely that we can reach valuable conclusions than almost anyone else with less experience and a vested interest. Furthermore - after fitting the rear bearing support - even racing crankshafts that had failed big ends (for entirely different reasons) never had any more wear on the rear main bearing or any other main bearings - proving that the extra support stabilised the flexing. Racing is the place that this mainly shows up because it is all manual clutch work and using change down to slow the car on braking applies several times more loads to the rate of deceleration that accelerating and deceleration throws things off centre with the slightest off centre forces and the overhang allows the crank end to bounce from side to side as the amplitude reduces - wearing the shell. So - by all means entertain yourselves immediately knocking the explanation but please no more until you answer my questions above. Fingers crossed the pictures come out (not sure how to enlarge them - sorry). Baz

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Thanks Baz. Emailed you yesterday morning. Definitely looking forward to reading the report.

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Thank you for contributing! Now you know why Raby and other experienced M96/97 builders have pretty much reduced or even stopped their contributions to this forum. A few people with fresh engineering degrees or experience in just one area (e.g. Bearing design) pop in to pontificate on one aspect whilst ignoring the fact that engines are complex and their development requires multiple engineering disciplines and years of experience to bring to fruition. I hope you ignore the internet experts and continue to share your knowledge. The vast majority of us appreciate your insights!

billh1963

I was thinking that?? Heads should be fine, don't deck them unnecessarily as when you need to get them machined , there's no meat left on them then and your screwed!

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If my tone came across as disrespectful it wasn't the intention and I always appreciate descriptive posts by pros. Doubts and questions is part of trying to makes sense out of this. Thanks for contributing.

Thanks for the support guys - I am just short on patience at the moment with all the difficulties faced because of Porsche being shut and spares unavailable (hopefully getting back on track now). Many of the customers that had their jobs delayed now assume that we can throw a switch and overnight finish all the cars! So when I try to help with other issues it is trying to have to defend conclusions from others without the experience, qualifications or knowledge - but I should always be more patient and try and help (I know) - just difficult right now - sorry. To be fair most of the problems with these engines took a very long time to analyse and find the true causes to, looking at a lot of different examples, trying things and eventually the penny dropped. The original "D" chunking and IMS bearing failure - was not like that - the cause was obvious from the outset looking at the design and measuring parts and were proven over the following years (despite others disagreeing) which is why all our liners have a top hat location to stabilise the block. However the cause of bore scoring on later engines took very much longer (too long in fact) but we got there in the end. Racing is a big help because engines that would probably last for over 100K on the road will last about 1,000 miles at race speed (at the front of the pack) but several seasons (near the mid field and back) - the difference in that small increase in aggression is amazing. But racing does help find the weak spots and prove the results of modifications. Most road users have 100% reliability after our rebuilds but of course if they drive them like they stole them (although they should be able to) long term reliability still eventually suffers a little in some cases. We now have 3 reports on:- the main causes of engine problems, our very successful oversized engines and now the basics of crankshaft failures. Yaz - I should have given you a different E-mail address (now edited correctly on the original post) it should be [email removed] if anyone wants a copy (Yaz just drop our Sharon another request please on that address to make sure you get your copy). For track or racing users there are longer reports going into oil pump weaknesses and Accusump issues and if there is a demand I will re-write them to suit the pubic and add them to the list. Baz

Thanks for the detailed explanation Bazhart. I've learned a couple of new things from your posts.

@yaz996 Can you explain in detail what the initial start up procedure was for this engine after your work was completed?

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He got oil pressure.

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How he got oil pressure is my question. Was the oil filter filled with oil prior to the start up procedure? Following a procedure doesn't mean that one will experience a positive result. Often people;le believe they are afforded (entitled to) a successful endeavor only because they "did everything right". This is engine building, there are no entitlements, and luck plays a role as well. Engine builders are heroes, or zeros.. There's no in between.

Sorry I didn't answer NYC933's question. For the flywheel to kick sideways there must be a force to generate the movement. That force can come from connection between the clutch plate and the flywheel because it never connects perfectly square all round. It can also come from out of balance forces transferred from inside the crank along the shaft. It can be caused by harmonics and it can be caused by differences between cylinder firing impulse strengths. Whatever it is a mass rotating at speed concentrates the mass towards the centre but if it is kicked sideways (say by the clutch engagement) then the heavier it is the least distance it will move (because of its inertia), the lighter it is the further it will move. However when investigating these issues we have to adopt a pragmatic approach because there are always many different forces that can cause problems and there are not enough hours in the day to explore them all. Those photos show that the "eye" is the weakest part of the crankshaft (smallest cross sectional area). I will try and post a picture of the result of applying a direct bend to a crank to show how it bent at the crank pins and no where else. That huge mass on the end kicking sideways easily moved the end of the crank until it destroyed the main bearing and that allowed the oil pressure to bleed away that needed to pass up a hole to the much more heavily loaded big end. in a way it doesn't really matter which forces caused it to bend - only that the evidence makes it perfectly clear it must have done. Similarly when the additional rear support bearing was fitted we never experienced any main bearing wear anywhere even when other completely unconnected faults caused engine problems. I also attached a photo of the difference in cross section of a 944 crank and a 996 crank to show the extra overhang and much weaker flange sections I hope the photos come out OK - if anyone can explain to me how to make a phot go full screen I would be grateful - thanks, Baz.

WOW!

Bazhart, from where I'm sitting your theory looks very thin.... I'm not saying that you are wrong but can you please disclose more information so that we can evaluate if your claims and engineering are true? Like, what is the original bearings dynamic load buffer? How much do you increase it with your modification? What bearing are you using and how is lubrication sorted?

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We know Bazhart and his credentials. Would you care to share yours? Why should we believe you?

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Yep...I stand by my post #395

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I agree with Scott. Baz is sharing what he has learned from decades of work on Porsche power plants. Instead of calling out Baz, perhaps Nick_L could contact Mr Hart�s office for the engineering particulars. I trust sources like Hart and Raby because the proof is in their research and development and the engines they make. Haven�t met either man, but I have a decent engineering background and nothing either man has ever written or said about these motors made me say �that doesn�t compute.� Countless times I have said, �that makes more sense now!� In Nick_L�s defense, I often want to learn more about what big brains like Baz say, so finding out more about the data used to produce solutions is important. I just go about it in a less abrasive fashion.

Sorry Nick_L I am not contributing to this post in order to spend hours explaining myself (when I already make available a brief report explaining it all), it works and anyway neither you (nor anyone else) has explained how the end number 7 main bearing in the picture was worn away by the end of the crank but not the number 6 unless (as I maintain) it was bending). Until anyone can provide an alternative explanation for that (especially as it was not bent 0.5mm one stripdown - just 0.1mm) it just becomes an attempt to knock valuable research willingly shared with others for no valid technical or even logical reason that I think anyone can understand. The picture of the "eye" cross section shows why it is so weak at the edge of the crank pin and the picture of the bent cranks (bent with little load in a normal press between centres) shows how weak that section actually is. Regarding lubrication - what on earth do you expect me to say" oh we forgot about that" - such massive disrespect is frankly unbelievable especially since the modification has been proven to work. Or do you just want me to tell you all what we did, how we did it and what we used etc all our intellectual property and expensive to uncover and deliver - sorry - if you don't like the explanation then just forget it - you are not going any further with it anyway. After modifying several engines, one experienced a big end failure that broke the rod (for reasons caused by a mistake on behalf of the owner with oil delivery) that wrecked the number 6 big end but the crank remained perfectly true and all main bearings were untouched. In fact since fitting the additional rear bearing - main bearing wear all along the crank has been negligible (implying that harmonics are not the issue). Finally - you can request out report from [email removed] - to find out more - but it is not the full picture (although should answer most of your questions). We went on from there to find significant issues with the use of an Accusump (and connected components) that have resulted in us developing a new oil pump - but like anything else - we need to test out the result and the virus has stopped all track testing over here. We will not share the details behind this until it is both tested and available - and yes - for purely commercial reasons. I am happy to get involved on here more deeply but only after you (or anyone else) can offer a reasonable alternative explanation of how the number 7 main bearing was worn down by 0.5mm radially before the big end failed while the number 6 main bearing remained untouched. Baz p.s. - I am not an immodest person but if you want to test my early career credentials you can refer to my e-book (the pursuit of dreams) more info on https://payhip.com/Barry Hart

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Bazhart, you came on this forum and presented your product that you would like to sell. You need to accept that people will be sceptical, after all this is a discussion forum. Especially since the information and pictures you have posted rather clearly indicates(not 100%) that it�s not an overloaded bearing failure. The fact that you are trying to say the 996 crank is weak and then comparing with a 944(comparing bananas to hockey sticks?) I would say is misleading. Just showing pictures of cranks that you bent in your workshop press is not very constructive, it�s not built to take those forces as you know. Can you compare it to a modern GT3 crank so that we can awe about how strong/beefy the 996 crank looks instead? Will your product work? It may help to some degree but really not much, for the issues you have shown. I would say you are treating the symptoms, not taking care of the problem. Usually what happens when engineering is forgone for mechanics logic. I should follow your lead and say: I will not spend hours explaining myself. But, I will actually help a bit and give you a clue(from the information you have given). Look at the bearing. It�s discoloured. This will not be the case if it�s normal overload. The fact that you miss this crucial part is baffling me. I will quote you and take your advice: There is a company in Germany with vastly more experience than you, in the order of 100x-1000x and some decent amount of capital. The name of this company is Porsche, I think I will stick with their engineering. They have already been at the M96/97 for a decade.

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interesting statement. Every major car company out there has released cars that have had major engine issues...Porsche and BMW come to mind. In fact, almost every 911 since the mid -70's has had some engine issues that owners and aftermarket specialists have had to sort. If Porsche has such excellent resources and infallible engineering, why were they sued over the IMS bearing and why do these type threads even exist? I love my 911's. But, I'm not a "kool aid" drinker. You should not be one either.

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Please stop, youre just embarassing yourself and its just cringe worthy

I'm trying to help Yaz here (it's his rebuild thread after all). Does anyone seriously think his rebuild mishap was due the fact he did not have Baz product?

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If you're trying to help - then let's see your answer. What caused this "mishap"? Remind us - what product is Baz offering that would have prevented this?

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Unless I missed something, the discussion about what happened to Yaz was never said to be caused by the lack of that extra bearing. The discussion simply just went in a different direction and ended up where it is now. This almost could be a separate thread but the important part is that someone that's heavily invested in the 996 engine development is willing to discuss something that's not shared by anyone. This is valuable information if you do all the work yourself.

OK I will try and attach phots of GT3 and Gen 2 cranks from which you will see there is no overhang at the end of the crank because the camshaft drive is taken from the other opposite end. It is the inclusion of the drive for the cam chains that left the flywheel dangling out there with a multiple of many times the bending loads for any given sideways jerk on the flywheel. The higher the torque output from the engine the higher the resulting acceleration of the flywheel and any jerk to it might have been an influence.. I have just been trying to offer Yaz something else to think about that we have found relevant in case it helps. Although we have carried out this modification to a few engines they are mainly for racing and anyway they can only be machined on our newest CNC bed Mill which is in use daily carrying out the finishing machining on cylinder blocks for standard rebuilds. Commercially it is not viable to break down the set up to carry out the necessary machining. To align the engine when the base it no longer square to the centre of the engine is difficult. Because the height is greater than the base dimensions we have to use slip gauges in one tenth of a though increments to mess around until we get the centre of the cassette in line with 2 tenths - and before we machine the new bearing location. Then the machining itself is not easy and anyway we need the crankcase and cassette crank carrier to align it (which is probably impractical unless it is in the UK). So I am neither offering a product nor touting for work - just trying (in vain it seems) to communicate the results of a lot of tests, as lot of work and finally a successful outcome that might help poor Yaz to avoid a repetition on top of that if the cassette needs replacing it will not necessarily line up in the same place within the crankcases and since the new bearing hole is already in place we sometimes have to reposition the dowels and fit stepped dowels to re-align it. It's not a job we seek to do but it does solve the problem. I was not trying to create orders nor interested in doing the job for anyone other than a regular customer and UK local competitor who has had this problem and needs help from us to solve it - when we could only fit it in during the inactive part of the season when we have a few to do at the same time. It is not our fault that Porsche designed the engine with a long crank overhang and until someone explains the above failure differently - and how our modification eliminated it in the UK - I am really not interested in trying to be made to defend something I don't think there is any need to do from anyone with less experience and who has not dealt with it before anyway. Of course the GT3 has a stroke of 76.4 and not 78 (996 3.4, and Cayman S 3.4) or 82.8 (996/7 3.6 and 997 3.6/6 3.8). the shorter the stroke the bigger is that "eye" section and conversely the longer the stroke the weaker it becomes. Now let's try the pictures (which all seem pretty similar to me on crank web flange thickness). . GT 3 flywheel flange right next to the main bearing. Showing the small cross section and weakest area Very similar Gen 2 web flange thicknesses but no overhang.

Probably should have included this 996/7 photo for comparison.

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I can't believe I'm weighing in on this dumpster fire... To speak in engineering terms, Yaz is now in the middle of an Engineering Investigation / Root Cause Analysis on his engine failure. Part of that process is to identify all possible failure modes that might result in the damage/failure that was observed in the system. For this to be thorough, all possible causes need to be included, especially those that initially seem unlikely or even impossible. It is only in a later step that further investigation, analysis, inspection, etc. will be used to rule things out. Bazhart's contribution of observed failure modes was on-point and helpful in this case. Yaz might look at the provided data and technical reports (which I have not), along with his engine's condition, and determine this to be an unlikely source of failure, given perhaps the very short run time, and if he never met the conditions that Bazhart described which can lead to this failure, but that's for him to assess based on the detailed data he has which we don't. We've just seen some pictures. No, he actually said the following, and then offered his internal technical reports for free. This is the best possible type of information that Yaz could have received. Bazhart is helping Yaz to complete step one of his RCA, all possible causes of failure. Your perspective would seem to be that a commercial builder is not allowed to contribute technical information to the forums, since they also have products to sell. However, as discussed above, they are the most likely to have enough data to support a reasonable RCA. Otherwise you're left with the home DIYers (like me) just guessing and speculating. That's not engineering nor mechanics logic, that's just 'keyboard warrior logic'. Last, I believe that your faith in Porsche is misplaced, and there is plenty of evidence to support some skepticism. (IMSB?) Don't get me wrong, we all love these cars and Porsches are excellently engineered overall, but we have to acknowledge that Porsche worked on the 996 from perhaps 1995-6 (early engineering) through to perhaps 2003 (on the last 2004 model), so 7 years. Further, Porsche was not doing well financially at that point in time. They were looking to cut costs, so they were not in a position to make the best engineering choices, they were working in a tradespace that included cost as a major driving factor. It would be incorrect to assume that their design is the best engineering design. Their choices are the best design within an acceptable cost. On the other hand, most aftermarket builders have now been working with these engines for 20 years or more. Further, their market is to enthusiast who are willing to put money into these cars, so the cost/performance tradespace is different. I'm sure cost is somewhat a factor, but largely, the aftermarket for enthusiast is less constrained. The commodity/appliance buyers don't have their engines rebuilt. This makes it very likely to get excellent engineering solutions (better than Porsche's) from the aftermarket. Yaz, back to you. I wish you the best and look forward to updates!!

Say what? The same company that gave us a crap AOS (located in a most difficult location to access) with a diaphragm that can fail if you look at it crossways? The same company that cut costs and corners with a cylinder coating that doesn’t stand up well over time? The same company that gave us a very poorly designed, but cheaper, IMS bearing? Then made the IMS worse for later M96 versions? Soft touch paint, pleather and plastic interior on a, then, $85,000+ car? I agree Porsche has a large group of talented, even gifted engineers and designers; however, accountants had the sway and decided to cut quality for profit on the 996 and the M96 motor. Porsche did not have much capital when they designed the 996/M96 series. I will anecdotally say, at that time, Audi was the company in Germany making quality cars. And go... By the way, Nick_L, where do you get your data to support your “100x-1000x” claim? Just wondering. Sorry about continuing the hijack Yaz, but I’m done. Good luck on getting going again.

Nick L I think you should do some background research on Baz Hart and Hartech before you start questioning his knowledge and integrity! These guys have done everything there is with the M96 /M97 , they have developed fixes to many problems with these engines, won race championships with these engines. Baz is a legend and trust me he doesn't need to come on here trying to peddle his wares !! They run a full machine shop next to their repair shop, all there engine work and developments are done in house , they have there own cylinder design,all the machining is in house , this isn't some two bit garage (engineering foregone for mechanics logic??) , trying to make a few quid on marked up parts! I can't believe your patronising comment , "there's this big company in Germany with more experience" I think when porsche made the M96 engine staring down the barrel of bankruptcy, they had to make compromises , have identical parts on the engine , use less tooling, presses etc, that's why there's a cam chain at the front and a cam chain at the back making the crank longer, it was cheaper to cast one cylinder head then just flip it round to fit the other side. This isn't us questioning porsche and making out we are better , this is fixing weak points in a design that was built to a budget as best as possible . This is what owning M96 is all about, it can be tough, the cars are relatively cheap to buy initially but to run one properly long term, you either need deep pockets, a good tool box, luck or a bit of all three! I take my hat off to the companies that put countless hours into research and development , like Hartech and FSI , Hartech is not far from where I live and they have helped me out with my engine rebuild. To be honest , I had no choice but to take it on myself, I didn't have the money to let them do the whole build , they machined my cylinders for me. I rang them countless times for advice , they could have said get lost pal, come back when you can afford us to build your engine but they didn't , they helped me , I got my car running, they are good people ! Baz deserves better respect !

In the interest of keeping this thread from turning into a dumpster fire... I'll provide updates eventually, but the root cause analysis is being done offline. Most of the comments and suggestions are very appreciated, but there's only so much to be contributed in this format. If I haven't mentioned it previously, I'm an experienced engineer with most of my work focused on the test and analysis of systems far more complex than this engine. While I can relate some experience, this project is a different beast all together. Could have done without the extra hit to the bank account, but I love this ****. I've already learned more from this project than any year spent at university or in my field. Thanks guys.

Hi Yazz Sorry yes we should stick to the origin of this thread which is your problem. I was wondering if you could measure your damaged crank to see if it's running out of true , which may lend towards the theory Baz has given you , which ever way obviously you now need a new crank anyway, maybe the cassette needs measuring to see if it's still running true? Please keep us updated on any developments you get , I'm just replacing a rattly flywheel on my car and am now worrying what stresses it may have put on the crank, next fashionable failure mode for the M96 maybe ??

When a crankshaft bearing surface gets red hot it will bend the cranks so measuring it now won't really matter.

Yes I did think about that , so what's the play, check the cassette is ok , source a new crank and bearings, clean and rebuild, on the presumption that the crank took out the bearings? I know it's not one of the most favoured company's and it didn't do itself any favours with the vid of the milling out of the crankcase for the oversized ims but they have now got a support bearing in the market for the crank which goes in behind the RMS then a special seal goes in, could this be an option for rebuilds to prevent this happening https://www.europeanpartssolution.com/rear-main-seal

Noz1974 - that's actually quite a good solution that is at least viable (and gets us out of expensive and disruptive machining). it accepts the overhang causing problems, corrects the out of alignment of the cassette and RMS hole and provides a support to reduce flexing, Our solution is a little more sophisticated (but verging on impractical for us to implement) so there we are -a simple way out for everyone. Yaz - in view of the way this has drifted (and that I didn't realise your engineering and analytical background) - if you send me your private E-Mail address to [email removed] - I will forward our full report (that you will find much more valuable than the short version). It is too detailed and technical for most but you should find it useful. I will also include a complimentary copy of my book (that I think you will find interesting) although I doubt you will have time to read it now. Good luck, Baz p.s.just to finish my original point - after stripping the failed crank only had 0.1mm bend (which is quite normal) but it bent enough to wear the no 7 main by 0.5mm radially - then springing back to 0.1mm - and I see no one has offered an explanation as to how that can happen if the crank does not bend! .

Just to try and finish off this subject - I want to answer Quadcammer's dismissive post about the benefits of showing a picture of the bent cranks and 944 comparison. Having always disliked the overhang (that I have not seen on any other engines) and then having concluded that the end must be bending - it was important to establish how stiff it is. With 2 scrap cranks about to be binned - it was quick and easy to bend then with hardly any load whatsoever exactly where the cross section is weakest and the crank would have had to have bent for it to wear out the rear main. After bending until the flanges touched we continued up to 40 tons and then checked where any more bending took place - and it was only at the pin "eye" which was a multiple of many times weaker than anywhere else on the crank. A 10 minute test that only cost that time but amply confirmed where the weak spot was (just as we thought it must be). The comparison with the 944 crank is relevant because it is many times stronger. I appreciate that an earlier 911, GT3, Turbo or Gen 2 has similar dimensions to Yaz's - but the cranks flywheel does not overhang and that multiplies the bending may times over both in magnifying the forces that would bend the material and the distance they flywheel flange would move relative to the centre line - if it ever did. The solution mentioned above is a great way to re-align the RMS and provide a support if the crank flexes. I will be asking them if I can buy one (and no - not to copy - if specialists make a solution we prefer to back them over quantities rather than halve them for everyone). Our solution uses an aerospace ball bearing race but for road use (and probably racing) that one seems a good and really simple answer. I am not sure that is why it was created - probably more to correct the out of alignment of the centres and the resulting seal weep but the cranks will only whip sideways rarely (and it more the flapping that follows that wears out the rear main). By restricting the movement it almost eliminates any whip so even a plain bearing might last well in hard conditions. Baz

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Wasnt me, bud

So Sorry Quadcammer - my fault - it was not you it was Nick_L - just put it down to old age and rushing things please! Baz

Baz Yes I thought it looked like it had a chance at correcting the problem, I was thinking about lubrication though? I think it must just get splash lube from the inside of the case , got my engine out at the moment for a clutch so might put one in , see how it goes !

Looks a good plan for a road going car occasionally used on track without slicks. I will try and test one and report back. Not sure why it needs a tool to squeeze it in as the RMS hole is usually out of true to the crank and I assumed the Loctite was to allow the eccentricity to be taken up by the Loctite? which would require the sleeve to be a little smaller than the hole. We too use splash lubrication (plenty flying around from the IMS intermediate and cam chains) and being a ball bearing in ours we don't need much splash anyway - but it is a clever practical solution that can do no harm as far as I can see -and I assume doesn't require any crankcase machining (unlike ours) ? It would provide some support when the crank tried to kick out of alignment and when it didn't (which will be 99.9% of the time if not more) it wouldn't be touching anyway.. Baz

Think I'm overdue to get put some life back into this thread... First off want to say how thankful I am to the forum contributors. Especially thankful to Charles and LN Engineering for going out of their way to help out with the rebuild. Also thanks to Mike (Mpfaff) for sending me his extra crank carrier oil baffle. As wild as this year has been (for everyone), I also had the pleasure of welcoming my first child into the world three weeks ago. A beautiful, healthy, and rather large baby girl. While sourcing parts and waiting on the engine block rework, I was able to knock out some home renovations including the nursery. Been busy all along, but fortunately timing worked out such nothing ever felt rushed (Can't rush success...). I'm going to break up the details into multiple posts just so it's easier to collect my thoughts, but let's start off with the timeline: All parts were received mid August (again I'll get into those details in a subsequent post). The engine rebuild was completed on Sept 10th, and installed on Sept 13th (not a Friday). Snapped the integrated bolt on one of the the diagonal strut braces. So held off on the initial start-up until the replacement was delivered and installed. Initial engine start-up on Sept 20th. Rather uneventful this time around, but somewhat more stressful with the thought of the last engine failure on my mind. The same giddiness wasn't there for the first few drives as I was hawkishly watching the oil pressure. Then another scare came on Sept 27th around the 65-70 mile mark (To refresh everyone's memory, I spun a rod bearing on mile 69 the last time.) as I was seeing a slowly dropping oil pressure. I'll go into more detail later (and also discuss the root cause of the prior failure), but the issue was resolved simply with an oil and filter change. To wrap up this post on a positive note, the car passed CT emissions on Oct 18th. There's now 460 miles on the engine, no lights/warnings, and oil pressures have been normal. Cheers!

Yaz - Congrats and congrats! Now you have something more worthy of keeping you up at night.

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Awesome dude. Happy for you and it takes a big man to lay it all out there, good and bad... And a baby girl to boot ! double congrats. Happy to buy you a beer if lucky enough to have our paths cross.

So now for some details on the rebuild... Crankshaft was junk. Replaced the crank carrier just in case there had been any heat damage. There was scoring on a couple of the cylinders so those required rework. The debris that scored the Nikasil also did a number on a few of the piston skirts/coatings and rings. It was cheaper to just replace the pistons (there was also change of the design sometime between my previous build and Scott's that I'll get into later). Also replaced bearings, gaskets, timing chain guides, oil cooler, oil squirters, any TTY or micro-encapsulated bolts... yeah its a long list. Fortunately a significant number of those items were previously purchased from FCP Euro and covered by their lifetime replacement policy. Also elected to replace the variocam solenoids/actuators, lifters, and lifter carrier as those were all original to the engine. I did reuse my timing chain tensioners, but spent a good amount of time flushing them using Marvel Mystery oil. And of course reused the IMS Solution, but replaced the oil feed line. Oh yeah, and replaced one of the Carrillo connecting rods. There's a possibility it could have been reconditioned, but that might have delayed the build which I was trying to avoid (because you know the whole baby on the way thing). And last but not least, I decided to add the LN 2qt deep sump. It was going to happen eventually so figured why not now. The long block is pretty close to ship of Theseus status now as the cams, sprockets, sump plate, and oil pickup are all that's original (if you don't count the heads and engine case due to the extensive modifications). And to once again end the post on a positive note, passed 500 (another 40+) miles this morning. Home Depot is only a 6.5 mile round trip, but somehow got lost...again...and again. With the winter weather closing in, the driving opportunities are becoming fewer and farther between, but definitely getting my money's worth. New piston on the left. Completed crank carrier assembly. Into the bank 1 case half. LN deep sump Sorry for being a little light on the pics this time around.

On a positive note you had a arp head studs.... congrats on your new addition to your family.

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Thanks and thanks again Mike! Yup. ARP head studs and carrier bolts. Along with the FCP Euro replacements, actually had zero addition bolt costs this time.

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Trying to make it up to Thompson next year.

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[Image-only post; no author-written text. Original image references:] https://rennlist.com/forums/graemlins/rockon.gif

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Cool - keep me in the loop and I'll see you there.

Couldn't pass up a 55 deg and sunny mid December Sunday drive (especially after Saturday rain washed the salt away), but sadly that's probably the last one until April. Sitting at exactly 750 miles on the current engine build. Morning temps will be back down to the upper 20s tomorrow, and we're expected to get a foot of snow this week. Now looking forward to my list of winter projects. The big one is a new suspension to go along with the new engine. Total mileage is just shy of 115k miles (with receipts covering the last 75k) and only a pair of shocks and a drop link have ever been replaced. Most parts are already patiently waiting in the garage with the exception of my coilovers and some hardware. Also going to be doing some brake work. In particular Spiegler SS lines to go along with rebuilding and powder coating the calipers. Probably go non-traditional on the caliper color. Leaning toward Mexico blue at the moment, but would love to see pics and other suggestions.

Yaz, congrats. Impressive work. What was the root cause?

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Now there's the million dollar question. The actual root cause would be me not going to same level of detail and research for the install and initial start-up as for my engine build. As for those details that led to the engine failure, everything is right in the RND/Nickies documentation available on the LN website. The key highlights: "Ensure the battery has a FULL CHARGE; do not attempt to start a new engine with a weak battery." "DO NOT REMOVE THE OIL FILTER AND PRE- FILL WITH OIL PRIOR TO STARTING." (Yes that line is actually in all caps in the RND documentation. For more detail, please read the thread: https://rennlist.com/forums/996-foru...-pre-lube.html ) "Proper engine oil system priming and break-in is critical... excessive cranking will cause rod bearing failure ..." I should also address the scare I had with dropping oil pressure earlier on with my current build. Cutting open the oil filter revealed crushed/collapsed pleats. A couple theories on the cause: 1. Oil pressure relief valve became stuck, and the high pressure crushed the pleats. Slowing the flow of oil and resulting in decreasing pressures. 2. Excess ARP fastener lubrication on the head stud nuts and washers clogging the oil filter. Something that has been mentioned on other forums. Apparently the lube is graphite based and no longer contains Moly. Fortunately the oil pressures returned to normal after an oil and filter change. Now its also possible a crushed filter led to my bearing failure as I can't say that I was paying close attention to oil pressure during my abbreviated time driving that build.

Thanks for the excellent info and awesome write-up.

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Filling the oil filter before start up is a huge problem, and leads to lots of bad things, like Yaz experienced. I have seen this happen too many times to count. BTW_ I wrote the RND engine break in and first start instructions for RND when SSF Auto Parts had the program, and I was their consultant. That said, lots of the things in them only apply to RND engines, but the oil filter pre- fill applies across the board.

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Why is filling the filter a problem?

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You can ask Yaz why it's a problem, as well as dozens of others who have made the same mistake- because they didn't know, what they didn't know about THIS engine. The filter is after the oil pump. With a new engine you have 1/3 of the primary oil system located above the oil pick up tube, and filled with air. The oil pump tries to push the oil through the filter with air... Ever tried bleeding brakes and let the fluid level run low, and suck air? How long did it take you to recover from that, and remove all the air? Same logic here. Filling a filter at an oil service is much different, but I still don't do that, either. I want the air to be bled by the column of oil pushing it through the system, not vice versa. I've started 700 engines after I learned my lesson about filling the filter, just like Yaz did. The only difference was, I didn't have anyone to help me figure out what I did wrong. I had to make the same mistake twice. The first time is a freebie, anyway.

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Ok, thanks, that makes sense.

An interesting side note: some cars, like my MB, have a cartridge filter mounted upside down. This makes it impossible to fill it before installation. I’ve always wondered why, maybe this is the reason.

I just did an oil change on my GF's Audi A3 2.0T - same^^^

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So do Mezger watercooled engines, and the 9A1.. Aircooled cars have the filter mounted sideways, which is also impossible to pre- fill.

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Both my Lexus's have a bomb proof horoizontal paper filter housing that must weigh about 2 lb's.