Jandackson .2 rebuild

Experiencing drastic oil pressure drops in even slight turns in normal driving combined with pretty glitter in the oil has pushed me to start the rebuild process. so as to not duplicate any information already documented in several rebuild threads (Ashai stands out), I will try and keep my posts to lesser covered items. Starting with the bottom end, I will note that my oil temps appeared to be very high. Unfortunately, I only have anecdotal evidence of this since oil temps could not be measured. symptoms include oil pressure leveling off at 3- 3.5 bar after 30 to 40 minutes of freeway driving. Oil would not go past that reading even above 4k rpm i changed to Motul 5w-50 in desperation. No improvement once up to temp. see below for pics of my mains. Based on my limited experience reading the tea leaves of worn main bearings, I conclude the markings are (swiping) are from overheated oil and oil starvation. Experienced insight welcomed.

How many miles on the bottom end ?

100k on the motor. I have out 50k of that. Rod bearings are the apparent source of the glitter as the tops are worn through the babbit into the copper. Crank appears ok but am sending it out for inspection. No scoring on the bores and the Fe coating on the pistons is intact. Wear on the valve train is minimal. Heads are at Hoffman and checked out ok. If not for the oil pressure issues, this engine would still be in service. I need to figure out why this happened. Oil temperature is my top suspect.

For 100K crank bearings looks OK, would definitely pull oil pump apart and mic and check for wear, and the oil pressure regulator valve and spring, I would also take a close look oil suction side tube and o-rings for any way you could have been sucking air. I'll also add I see no discoloration from diluted oil with fuel or coolant.

JohnCA thanks for your recommendations. I will definitely inspect the oil system, especially the intake side as you have noted.

@BRS-LN thank you for the reply in the �factory short block� thread. I agree that my question was out of place in that thread so moved it here. I have a micrometer and will measure all the journals in three planes to get an average. Then do the math for the .001� clearance per 1� dia. The crank was lightly polished when I had the balance done. I took rough measurements (in one plane) prior to the polish so have a baseline for what was removed. Quote: Originally Posted by jandackson Look, I�m just trying to assemble a motor with @BRS-LN parts. And I would rather only do it once. Since they sold me the parts I�m only looking for some guidance. Sounds like I need to wait for the book. Or, I forge ahead and �assume� the bearing clearances are correct on the main and rods. A lot of these motors have been built by enthusiasts without these clearances known (how do you adjust the clearance if you cannot buy different bearings or machine the crank?). If you need a particular clearance, I am sure we can help you with this. The first step is to measure the clearances that you have in different axes and see if you lack the minimum clearance based on the old .001" per 1" of journal diameter rule in any of the axes that are measured. Clearances are adjusted by different methods, generally the crank carrier requires line- honing if the measurements are not adequate. They are almost always too tight if adjustments need to be made. In other cases the crankshaft is polished, and in other cases the big end of the rod is slightly opened. All of this is honestly better suited in another thread, since a factory short block gives you whatever clearances that the factory gives you, and that's what the topic of this thread is.. Sorry for the continued infiltration.

While assembling the crank carrier using ARP screws, I noted a paragraph at the bottom of the instruction sheet that indicates that bearing clearances must be checked using the new torque values for ARP fasteners. I checked the clearances using the stock screws at the stock torque value. Has anyone who has used the APR crank carrier screws rechecked their clearances and found them to be different than with stock screws?

Sorry to say but, you always check clearances with the bolts you are using with the torque that the bolts call for. Saw on a show once that they torqued down main caps with studs and then regular bolts and the clearances were different. Chances are they will be both acceptable in this case, but I wouldn't risk it.

Thanks @amargari for the reply.

Need to replace. Anyone have a source for one? This is the snap ring that holds the IMS chain tensioner to the shaft on the crank carrier. I found this PN 90004100401 And it can be found here: https://www.pelicanparts.com/More_In...41-004-01-OEM# and/ or here: https://www.fcpeuro.com/products/por...he-90004100401 Of course there are no dimensions or application for either site so wondering if anyone can confirm.

Quotes source post: 18653614

In the parts catalog it's described as 21 90004100401 circlip 10 X 1 �0.59

Quotes source post: 18653614

I rebuilt the majority of my 4.0 engine using parts from FCP euro where applicable, including this one!

Thanks @e30rapidic . Ordered!

Well I have managed to make progress on this build despite some setbacks. One area have not figured out yet is how to seat the front console all the way. case halves are joined and all fasteners torqued. Following Jake�s video, I am now supposed to push the console closer to the block and install a few more screws. However, I can�t get it to go any further. It is in past both o-rings with about 1/4� left to go. I can rotate the console and the engine rotates as expected. Appreciate the help.

Anyone? Did this slide in for everyone else that has built one of these motors? Maybe I am being paranoid about breaking the console.

I would remove the oil pump console, and using a dial bore gauge, mic the hole for the console to make sure it is round and is sufficiently larger than the snout of the console...( measure in three different axis) Jakes procedure is a bit different from the Porsche Technique for this..Porsche uses a special tool that expands to size the hole as the two case halves are put together... Jakes technique uses the console itself to size the hole... Use some mics and a bore gauge to measure the hole and the snout to get the actual clearance you have to work with...( or take it back apart and do it again).. Good luck !!

So what you are saying is "clearance is clearance" and "interference is interference". If you know that, you'll go along way in life! I once tried to put a seal in that was about 0.035" too big for the hole, could not figure it out until I measured it up and determined I had the wrong seal. When I got the right one, it went in no problem.

Thanks @Porschetech3 and @Paul Waterloo for the suggestions. Between both of your suggestions I figured out what went wrong. I believe I had the console too far out when I torqued the case bolts. This sized the hole too tight. So I removed the torque on the front case bolts and was able to reinstall the console all the way in. Then retorqued the bolts. Sealant didn�t appear to be disturbed so we will go with it.

Welp, making progress. Bank 2 pistons were installed last week. Today finished up the oil pump, console, water pump. Now prepping for install of heads. Has anyone used the ARP stud kit? Jake mentioned in his video he doesn�t think they are necessary as the stock bolts are stronger than most will need. I�m going to use the ARO studs but just wondering if anyone else has used them. ARP HEAD STUDS INSTALLED

The studs look nice. I reused my stock head bolts as per Porschetech3's recommendation, https://rennlist.com/forums/996-foru...u-want-to.html and from a Porsche tech book. However; I imagine installing the studs is much easier as you have 4+ steps to torque down the factory bolts. Including two steps with a degree value. Your build is looking great so far.

Thanks @amargari Those were my thoughts too on the tightening sequence. These are tightened in two equal steps and done. No torque angle. Oddly, they are screwed into the bearing carrier �finger tight� and Loctite is optional. Im waiting on the spray gasket stuff Jake recommends for the chain box area and then will have the heads on. So glad the bank 2 pistons are done!

Quotes source post: 18736309

can you elaborate on the spry you are talking about?

Quotes source post: 18736577

To be clear, he isn�t recommending anything by name. However, he does recommend spraying the lower half of the chain box portion of the gasket with a spray type gasket product. Reasoning is that it will stop oil leaks that could occur before the head gasket has had a chance to cure from engine heat. (This portion of the gasket takes longer to heat up. In the meantime, oil can weep. ) Permatex 80697 Copper Spray-A-Gasket Hi-Temp Adhesive Sealant, 9 oz. net Aerosol Can , Orange https://a.co/d/0a2gIg7

Quotes source post: 18736770

thanks for the clarification. I saw that process on Yogi's video, but it wasn't clear what exactly he was spying on (at least I didn't get it). good luck with your build.looks awesome.

Today, after my chores, I reached a milestone with the build. Both heads are installed and ready for the valve train. as stated at the beginning of the post, I post stuff I have not been able to find answers to. I used the ARP head stud kit, as mentioned above. Installation was pretty straight foreword. The studs are installed into the carrier �finger tight�. Then I followed Raby�s video on the chain guides( he is kinda all over the place here. Install the guides but then in-install the top guide on bank one so you can access the cam chain box interior bolt ). He says he doesn�t think the upgraded studs are necessary. I bought these from @lnengineering before I realized the stock fasteners were good enough. The benefit seems to be a much more straight forward, two step torque process va the 4 step process with the stock bolts. ARP instruction are to �torque in two equals steps to 60 ft lb. Easy enough. Except 60 ft lbs is no joke! I was breaking a sweat after the 4the stud on bank 1! The only oddity, and I freaked me out when it first happened, after the initial 30 ft lb, I started to apply the next 60 ft lb the stud seemed to �yield� and the torque went back to a little over 30 ft lbs. But each stud took the 60 ft lbs. And that was it. All done.

I forgot to mention that I measured the deck clearance for both banks. The piston was below the top of the cylinder at TDC by about .005� to .007�. I could not find any information on an acceptable dimension so just noted it. According to @lnengineering , the pistons (Mahle) and rods ( K1) are all made to allow clearance for bearings and deck. So, I went with it because at this point, what is the recourse if it�s wrong?

Here is my experience with ARP studs (on a E34 M5). Not impressed, either with the studs or with the last builder of that engine. The torque that was used was way too tight and deformed the holes where the studs went through. The heads required a custom puller to come off the engine. I went back to torque to yield head bolts after drilling out the now to small holes. What a disaster that was. On torquing the head, the first step was 60 Nm (can't remember exactly) and I noticed that all the bolts loosened up after the first pass and I had to do another pass to re-torque all the bolts to that same spec. My guess is the multi-layer metal head gasket compressed and the bolts came loose.

@Porschetech3 So, are the M97 head studs also Non-TTY and therefore reusable?

Quotes source post: 18747894

Yes the m97 uses the same head bolt/part number as the m96 so non-TTY ....

The replacement exh cam screws arrived and the new int cam screws should be here in time for the weekend. So I will install cams and time engine. Now I am prepping for engine install and first start. I will use Driven BR30 for first start and apparently for only the first 20-30 minutes of operation. Is this what others have done? I am looking at the Driven HR5 10w-40 and the 15w-40 �conventional oil� on @lnengineering site. According to the literature sent with the block, these will work for proper break in of the rings. Anyone use these or care to share what they did use? Lastly, I have been avoiding buying the LN filter adapter install tool thinking I could make or buy a generic cheaper. It is on sale now so I may just buy it and move on. Anyone with experience installing this?

This is what I was told for the break-in. Since I don't drive it often, I am on my second oil change of HR5 at 2,500 miles and 6 months. My following oil change will be DT40.

Well that sounds like a good plan. Thanks again @amargari

It�s been a while since I was able to work on this project but finally made some headway. Engine it buttoned up and now installing peripherals and wishing I took better pictures during tear down. The current dilemma is how to install the RMS without spending $500 on the tool.

I used a 3D printed one on the 02 few months ago, it worked great, more than welcome to use it. got the plans here on Rennlist if you have access to 3D printer. BTW all looks great in the pic. I am in the same situation in finding time to pull the engine on the 04.

@JohnCA58 thank you for the offer. @meirschwartz has graciously offered a solution too that I will pursue. This forum can be a really great place. For those who are considering an engine rebuild, a word of advice: you cannot take too many pictures during tear down. Since the resources are less prevalent for assembling the peripherals, you will need your own records to get everything back like factory. I thought I took a lot more pictures than I did. Fortunately I was more thorough in bagging and tagging hardware which has helped bridge the gaps.

I have several gallons of old fuel in the tank that I need to drain. Does anyone know if powering up the car (connecting battery, turning on ignition) without the engine hooked into the DME will cause any issues? My plan is to use the fuel pump to drain the tank.

Quotes source post: 18832437

Pull the fuel relay in the driver footwell, and put a jumper between pins 30 and 87.

Quotes source post: 18832437

If you make sure the main power cable is well isolated/taped up so it can't touch any metal grounding surface, there will be no issues..

Thanks @yaz996 and @Porschetech3 . I will give it a try.

I have confirmed that the larger 3.8 oil cooler will fit under the intake manifold. The coolant line just skims the bottom of the manifold. It will be interesting to see if this cooler lowers oil temps.

^^^ I would recommend some type of rigid right angle connector for the end of that hose (maybe soldered directly to the oil cooler). With all the heat and vibration in the engine bay I think leaving the hose in that condition is asking for trouble (a kink at the very least, and likely crack or rupture)..

That hose has a molded 90* elbow. If it is touching the intake he can put another piece of hose over it as a wear protector but thats all it would need.

As @De Jeeper stated, the hose is molded with a 90 degree bend. I was planning on applying some foil tape to the top side of the hose where is skims the manifold to reduce abrasion. Otherwise, I think it will work out fine.

Cut the hose 1/4" shorter and shove it on the nipple 1/4" further.

Quotes source post: 18840877

That is a good idea. Not sure if the bend in the line will interfere with shoving it on a bit further. I will give it a try on the old line that I discovered has a hole in it.

I am replacing the trans mount since it is,presumably, the original part and I was starting to get some shuddering when backing up. The foam side pieces came apart in my hands when I dropped the motor. Anyone know the function of these? They are about $20 each plus another $12 to ship. Like many automotive parts, they are called something seemingly random that does not actually represent what they probably do. My thought was they keep dirt from entering the mount and extend its life. I may make something to do that rather than replace these with factory parts. What do it do?

​​​​​​​

the ones that came from my car are made of about 1/8" rubber. Before taking them off, I took a good look to see what their function is. they are not really touching anything so your assumption of them being some sort of dirt protectors might be right. you can definitely fabricate them yourself if you have the material and time.

I think they are intended to prevent klunking when the transmission mount moves under load.

Quotes source post: 18854027

that was my initial thought as well. however, if you look at this picture I took while still in the car, you can see that the gap between the rubber part and the mounting bracket is too large for the rubber to do anything. also if you look at the mount itself, you can see that the aluminum part is protruding about 1/4" passed the rubber. so if there is any movement (I highly doubt it) that can cause the transmission mount to hit the bracket, I don't think the rubber will be the one to prevent it.

It's $10 each so just buy it.

Quotes source post: 18854229

If I could locate them for that price then I would pop for them.

I just realized you got a Tiptronic. That�s why that part is different (and cost double).

Quotes source post: 18854412

Actually I have the manual. From what I can tell the parts are the same price. But that is not always easy to confirm. Either way I am certain this is not a critical part compared to the rest of the special, single use, made by elves parts that I have purchased over the last 12 months. If the custom fabricated parts don�t turn out I will buy the OEM parts. Thanks all for the input.

Delaware porshe

Quotes source post: 18854937

https://www.delawareporscheparts.com...er-99637525505

@yaz996 @De Jeeper Thanks for the links. My internet skills blow as I did not find those deals.

I look up part # ( using auto Atlanta,Sun coast,etc) then I go to Google images and input the part # and off to the races.

Alas the above part is for 99-01. The part for 02-05 is $17.95. Posted for anyone looking in the future. https://www.delawareporscheparts.com...g2LWdhcw%3D%3D

Quotes source post: 18855519

Call them up and verify. Those website parts diagrams are not always accurate. Catalog says 996-375-255-04 is for up to 02 (but that has been superseded to the -05), and 996-375-255-05 is for 02 and on. 996-375-259-08 that you linked is for the GT3 and Turbo transmissions.

Quotes source post: 18855561

GT2, GT3, Turbo, and 722.6 Tiptronic use the same transmission mount so it makes sense the isolator would be the same.

Last part to go on. Anyone know where it goes?

This bracket should be bolted to the block, left of the water pump. it should have two plastic clips holding the coolant hoses between the engine and the engine mount plate.

Here are few pics.

@meirschwartz thanks a bunch. I spent way too much time going through pictures trying to figure that out. Looks like I need the plastic clips as those are probable in pieces.

Well I found the plastic eclampsia that I conveniently left on the hoses. next issue is the y hairs manifold gaskets. What I got from FCP. The gaskets have sport diameter that is smaller than the head and what I removed originally. PN appears to be 99611110755 but the pictures show what I already received that appears wrong (1997 bitter and carerra). anyone run into this before? Old on top of new

Just put the old ones back on - they look fine�

The one on the right looks like Boxster 2.5-2.7 gaskets and the left one looks like 3.2-3.4 gaskets...

I have ran into this before.....you can get a complete gasket/o-ring set for a couple hundred bucks, but the only issue is it is for the Boxster 2.5 engine.. Every thing is the same and works except the exhaust gaskets..

@Porschetech3 I think you confirmed my suspicion about the application of the gasket. I bought this kit from FCP and found that it is lacking. I had to buy new intake gaskets, cam plugs, oil cooler orings and now exhaust gaskets for a 3.6. At least the gaskets are all high quality name brand/Porsche branded. Probably a case of you get what you paid for.

I received the correct exhaust manifold gaskets today. They match what came off the engine. The correct PN is 99611110755 Note that they have three �fingers� in the left corner vs the two on the incorrect gasket. They are also mirror images of each other which seems to coincide with use on a boxster.

I did not document the location of the large, round DME connectors before I disconnected them last year. Does anyone know which one goes where? I see one has white dots and the other blue on them (I didn�t do that).

I think I found my answer from @Ahsai on a different thread. �These are the X59/1 and X59/2 connectors.The top one has blue dots on the connector and the bottom one has white dots. I forgot which one is X59/1 and which is X59/2. The coolant sensor signal (blue/pink wire) connects to pin 12 of X59/2, then to pin B12 of the DME. The ground of the sensor (brown/pink wire) is merged into the ground connection of other sensors.�

IIRC they only fit one way, you can’t install them incorrectly.

Blue is the upper right, white is the lower left.

I went with blue on top and white on bottom and the result is the engine runs! This was a high intensity few minutes of my life! You Tube

This is awesome! congratulations.

Awesome. I enjoyed reading your build thread and the start video is an EXCELLENT finale!

Update I now have 25 hard miles on the engine. Drained the break in oil and it was an interesting grey color. Nothing alarming I guess but very thin (BR30). Had two coolant leaks that were just loose clamps. More concerning was the oil leak towards the back of the engine after my first drive. Let it cool overnight (me or the engine?). Came back this morning and found the IMS Solution oil feed line loose. Relief, instantly. I have been romping on it up to 4k rpm at full throttle then engine breaking pretty much the entire 25 miles on it so far. I don�t want to risk glazing the bores. All said, water temps are about 200-212 and the oil is tracking the water temp exactly. (997S oil cooler). Ambient temp here in sunny Sacramento is above 100F. Garage and tools cleaned and put away. Time to take a breath. Thanks to all for the help during this adventure. I will try and reciprocate.

Really Coors? Congrates, its always nice to get over the hump and have a running car again.

fantastic! great job!

Quotes source post: 18911162

Ha! I remember having my first Coors many moons ago, back when they were restricted from selling east of the Mississippi. I traveled west -- to Golden Colorado in fact -- and had my first ever Coors at the bottling plant! I thought it was excellent. That was in the days before all of the craft brews.

Really Coors? I had two! Nothing better after a long day in 106F weather.

At least it's not Coors Light. I'm 50% into my 997S engine rebuild. I should be done in a week and at that time, I will post my adventure.

Here is a cold start vid at about 2k miles. I replaced right bank upstream O2 sensor after it threw a code. It was running rough still and after some diagnosing, I replaced the MAF. Runs a lot smoother now. I get an occasional puff of smoke on cold start but the UAOS is dry as is the intake manifold. Doesn�t seem to be using much oil. I�m at 2500 miles now. Oddly, my OBC tells me I am getting 25 mpg but my calculations indicate more like 18-19. Gas gauge reads fine and I get the same number of miles out of the tank I used to. Can�t figure that one out. I think this engine would benefit from the 82mm TB as it seems to poop out at top end (yes, I took it to 7k the other day). But maybe it�s just no broke in yet. Overall I am pretty satisfied with the build and really glad I did it myself. You Tube

The ECU calculates MPG based on injector pulse width, so if you change injector size or fuel pressure the ECU's calculated MPG will be wrong.

Quotes source post: 19151051

That�s probably by design. The stock 3.4�s HP starts a downward trend at maybe 6800, and continues until the 7300 RPM redline. The 3.6 motor�s redline is less than the 3.4, so a 4.0 is going to struggle at 7k unless the cams/heads/intake/exhaust have been upgraded to accommodate the larger airflow of the 4.0. It�s no problem, though, the 4.0 is going to be faster than all of them because the torque and HP are likely higher across the board.

Quotes source post: 19151912

Didn�t change injectors or fuel pressure. Oddly, the computer displays fairly accurate total miles left despite an optimistic MPG calculation. And the gas gauge appears accurate. Or at least as accurate as it was pre-build. latest tank I calculated 19.6 MPG mixed driving so this engine is already getting better mileage than the factory motor.

Quotes source post: 19152066

I suspected (based on prior,limited, engine building) that the intake manifold and TB would be power limiting. I quizzed LN about this pretty heavily but was told the stock system �will support a 4l�. That is a fair statement but as we can see from Jake Raby�s recent work, new intake manifolds make a difference. Im not chasing HP here; the car is plenty fast and has noticeably more torque. The torque makes for a very entertaining car. If anyone is on the fence about a rebuild or what displacement to go for, my advice is to be bold and build it as big as you can.

Quotes source post: 19153933

Great advice. 6.2L

Quotes source post: 19154057

I thought of you @zbomb when i typed that! �No replacement for displacement�

Occasionally when I start the engine cold, I will get a cloud of blue smoke out of either bank accompanied by ticking noise momentarily. The UAOS tank is dry as is the intake manifold. The smoke only last on first fire and the ticking goes away immediately (sounds like lifters pumping up). Engine has about 2800 miles on the 4l rebuild and it nice and quiet the rest of the time. I am still running the Dino oil and it does not consume much. wondering if anyone else who has rebuilt their engine @lnengineering Nickies and pistons package experienced this.

I have the smoke for the following conditions: Start the car and drive an extremely short distance like moving the car in the driveway or a 2-minute drive to the store. Let the car sit for at least 10 minutes or so When I start the car, I get a cloud of blue smoke I posted the above on Facebook in the Porsche Engine Builders Group, and people stated that this is normal. On a short drive like that, nothing is warmed up and some oil can seep through seals and remain in the bores. When you restart the car, the oil burns off.

Quotes source post: 19163291

yeppers, same here! It will do it once in a blue moon if I start it up and move over a bay or something super quick and then shut off. If I drive it to work or a pleasure cruise, nada. I don't have any lifter noise or oil consumption. Runs super smooth.

I have seen the smoke after a short too. However this can also occur the next morning after I drive it home 20 miles the night before. Not terribly concerned (what can I do after all) just trying to preserve my new, fancy, expensive bores!

Quotes source post: 19164609

Nature of the H6 beast. Sometimes I’ve driven the snot out of the car for a good while and I’ll still get an “eff you” small cloud next day from my needy ‘Gen Z’ with Nickies. Never the same side, probably just depends on what valve is last to stay open to allow some oil to pool. Since I’ve done everything possible to eliminate failure modes, I stopped worrying and learned to love the bomb (smoke not nuke). Anyway, good luck getting Nickies to score.

Quotes source post: 19163291

Haven't ever used LN 996 nikies, but have used many times Millennium Tech nik jobs, same plater LN uses. Maybe a combination of not fully seated rings yet on fresh Millennium Tech nik job and lifters..? Millennium Tech nik jobs are quality heavy duty and if engine isn't hammered hard to fully seat rings when its time, could take a while to fully seat. Shouldn't be a problem though. Take a manometer blow by test. Maybe Skip will chime in and have a manometer blowby # for a fully seated 996 rings/cylinder seal. Also, if lifters aren't pumping up for a second or 3, and valves aren't fully open, could be causing a higher cylinder vacuum on the intake stroke and be sucking in some oil from the cylinder walls/sprayer/splash...? Are you running extra oil in sump because of track drain uaos..? jmo

12-14 LPM ( Liters per Minute) at idle 800 RPM, and 75-80 LPM at full throttle MAX blow-by are good numbers ..( lower is even better) This is what my Sally has @145k miles and has never let out a puff of smoke ( except when the AOS catastrophically failed a few years ago at Talledega, thus the UAOS Invention).. I have owned her for over 15 years and cold starts, short trips, crank and move a few feet, sit for 30 min then re-start , all have never puffed smoke...So they ALL don't do this.. Whether it is normal or not I think is kinda subjective, Porsche says 1.6qts in 1k miles is OK for oil consumption, but my car have never used anywhere near that much...It hardly uses any at all ( so little infact I can't even give you a number, maybe .5 qt in 2k miles?) In testing the UIDS and UAOS Track Versions in Extreme testing I have even overfilled by 2 qts and still had no smoking, In fact I am still 2 qts over and have been driving it around for months just to test, so smoke.. Oil can only get in the combustion chamber from a few ways. 1. from the intake ( AOS System) 2. from the valve seals ( but not likely since they lay sideways) 3. from the crankcase/rings ( very likely since they lay sideways and are not a perfect seal) Also if an engine is running rich or injectors are leaking it can cause oil smoke just on start up. The fuel will wash the oil off the cylinders and cause a bit of oil smoke especially on cold start or on repeated cold starts/ short trip re-starts. So my advice would be:: 1. check your fuel trims, and if near the limits, fix it !! 2. Test fuel pressure leak-down ( 2psi per 20 min is ok) 3. test your blow-by... if it is a little high, at least you will know why you get a puff of smoke.. It probably will not be something you want to fix,( and you can just call it normal like most are doing..)but at least you will know why..

Fuel trims are good Have not tested fuel pressure leak down however my injectors are new. May need to test blow by. Engine only has 2800 miles so that number may be high. I also got a CEL a couple days ago so need to investigate that. Thanks all for the input.

Quotes source post: 19164123

Yup, that is very typical. The factory pistons have pinned second rings with the gap such that it can't line up with the bottom of the bore. There are no aftermarket piston manufacturers that offer ring pinning like you find on the factory pistons.

Quotes source post: 19172299

Thanks, Charles, that is the technical answer I was always looking for. I now understand why there is a pin to keep the rings from spinning. Most engines I have built have never had a pin and generally, the rings spinning is not a bad thing. That was always with V engines. With a flat engine, I can see where the ring spinning and the gap being at the bottom could let a little oil leak through. On a cold engine the rings never get a chance to expand, so the gap is bigger allowing the oil to seep through easier.

@Charles Navarro thank you for the reply. That makes sense so I will stop fretting about it just drive it!

Now that I have 5k miles on the build thought it time for an update. I just changed the oil to DT40. The engine didn�t burn much of the break in oil and I don�t have anything in the UAOS catch can. I have replaced the MAF and both upstream O2 sensors (those due to CEL). I still have some weird hesitation sometimes when the engine is cold. Fuel pressure and leak down are in spec. Gas mileage in mixed driving is 18-19. Fuel trims are good as is cam deviation. My experience breaking in engines is minimal but they all seem to break in similiar to the gains one might get while working out. You build strength in the beginning and then plateau. Then after pushing through that you make more gains. Same with engine torque it seems. When I first fired it up is was down right slow. As time went on I could feel gains in torque and power but it felt dead past 6k. Then one day I romped on it and it made me giggle like a child. Seems to keep getting faster each week. The torque is crazy. I have to remind myself not to open the throttle at too low rpm to avoid all the myriad number of bad things that may happen to the engine. It just wants to pull. Passing on the freeway is a matter of squeezing the throttle for a second or two. At top end, it�s a bit scary. At 6200 I get another bump in power much like when variocam+ kicks in at 3200. I never felt that on the stock engine. All of this with the stock TB installed. It�s a lot of fun.

I have the cold engine throttle hesitation like you do. It’s like the throttle sensor recalibrates and “wakes up” after a couple minutes.

20k mile update. I had been chasing a bad hesitation that comes and goes. It�s usually at light throttle and presents the most just of idle. Sometimes it sounds like I have a hot set of cams and will trigger the engine light. Codes were for cyl misfire (various) O2 sensor delayed response and catalyst failure. Fast forward about 18 months ( I am patient) and I finally figured it out after replacing O2 sensors, plugs, coils (injectors were new at rebuild). mu clutch helper spring popped a while back but the clutch felt fine. I even forgot about it. Pulled the codes last weekend and among the cyl 2,4 misfire and O2 sensor and catalyst codes was the clutch switch encoder failed P0806. coincidentally, last week I Cheaper than the $100 Porsche part. We will see how long it lasts. noticed my clutch pedal was not returning all the way. It used to have some travel before engaging the throw out bearing. So I crawled under the dash to see that the spring assist had broken and relocated itself, causing the clutch pedal to not return completely. Removed the spring assembly and confirmed a broken spring. Without this installed, the pedal will not close the clutch encoder (not the start interlock switch). I think this confuses the DME as it is being told to run in reduced torque mode. Went to ace and bought a spring and popped it all back together. Cleared my codes and fired it up. clutch feels great now and the misfire is GONE. It�s been 4 days and the check engine light remain off so maybe I can get it smogged now (due last Nov).

Misfire is back. I knew the clutch could not have been the culprit. I found that the manifold butterfly valve switchover solenoid was bad so replaced that. Doing so has greatly improved the response on the highway. But the intermittent hesitation at low rpm is still present. I clamped the fuel evap hose and thought I saw an improvement. Replaced that valve and saw additional improvements. my long term fuel trims are at .80, which means the DME is pulling 20% fuel. AI has suggested the carbon canister could be flooded, causing a rich mixture when valve is venting to the manifold. AI also suggested I had clogged or broken cats that are impeding exhaust flow. I noticed the trim number go to .98 if I get after it a bit (not full throttle, just higher combustion pressure). since this is an intermittent problem, I tend to think there are excess fuel vapors coming in. I plan on scoping the cars to see what they look like and will clamp the evap line to the manifold for a while and see if fuel trims improve.