Let the rebuild begin!

This is a '99 cabriolet that was taken out by dragging it's belly on a gravel road. I straddled a ridge of loose gravel which made contact with the oil pan area and broke a hose clamp on one of the water hoses. The water leaked out and the engine overheated and then quit when my wife went to drive it the next day. When I tried to restart, both exhausts were dripping coolant. Now, after a year of procrastinating I have gotten started on the repair. What I've got to move forward on this project is: A core motor that I can use should the heads be cracked or unrepairable. Also, the shortblock could be used as a core should I need to purchase a factory rebuilt bottom end. I've got my shop set up with a reasonable set of tools including a 996 cam alignment kit, a lift and a hydraulic table. I've got a Bently manual. The only skill set I bring with me is a basic knowledge of mechanics from high school autoshop and about a dozen or more prior engine builds/refresh on my racing cars over the years (mostly v-8 and some imports). Please chime in with suggestions as I proceed.

These threads are always inspiring, well visited and very interesting. Keep it coming & Best of Luck!

Looking forward to following the project. Let me know the parts you may need since I took apart my failed 3.4 last year just to learn and have all of the parts. I will be happy to contribute parts as long as you post all the work you are doing and pay for my shipping. Hate to throw good parts away but I need to start getting rid of the stuff...would love to help a good cause.

Subscribed! But, what are you going to do about the road and the chance of the same happening again?

Looking forward to watching this unfold. I'm only a hobbyist mechanic, but happy to help in any way I can.

If I were in your shoes, I'd take the Knowledge gruupe online re-build/engine course. I think it would be $400 well spent. Good luck with the re-build!

Thank you for your interest and offers. The original motor had just been rebuilt/refreshed with bearings, hone/rings, updated rod bolts, IMS, valve job, gaskets/seals, waterpump and starter at the time of my purchase. The seller had receipts totaling $14.5K. I put a couple thousand miles on it cruising over the summer. I hope that the cyds remain round and are not cracked. If they visually look good I will take the shortblock to a machine shop to check for oval, taper and ?magnuflux? (unsure how to adequately mag an assembled shortblock?) : Lowpue: It's nice to know that someone has spare parts, should mine be unsalvagable.

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I came here to say this. Im glad someone managed to beat me to it.

I did look into this. Are you referring to the online, or the in-person workshop? What I surely will need help with are things like bearing clearances (?.0025 rods/ ?.003 mains?), bore specs, ... also, I've never set-up valve timing on a variable timed engine. It looks like you just trust the Porsche tool to get it right, rather than using a degree wheel? ... I'm sure I can get it apart. Getting it back together will be the journey!

"The only skills I bring is rebuilding a few racecars"... Only?? Haha, subscribed!

Read Ahsai's rebuild thread.

You won't be able to Mag anything until each component is disassembled, best part is you will have some great help in this forum.

Watch Glen's 986 fix videos on YouTube he rebuilds a 3.2 boxster engine step by step, I used it rebuilding my engine to help figure a few things out it's worth a watch!

Best of luck - attaching a link to our site's DIY tech articles, hope this helps you out a bit. Let us know if you have any questions. https://www.pelicanparts.com/techarticles/996_tech.htm

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Got a link?

So the first few steps, ....after the token "make sure that the car is secure on the lift and that you have your battery disconnected" should read: 1) be sure that your jack pads do not cover the screws to your rear tray or the bolts to your rear cross bracing, as you will need to remove these. 2) There is a "hidden bolt" behind the a/c compressor. (Why, with all of the great engineering at his disposal did Mr. Porsche decided to hide this bolt ? ... one can only speculate). With the "proper" swivel and extension it is said to be doable. However, you can't see it. You can't feel for it. The swivel and extension that I had didn't do the trick. Why didn't Porsche merely cast a relief in the intake runners to accommodate this? My suggestion is to pull this bolt first. If you can't get it, then reconsider dropping the engine yourself. I'm on my phone now, pics to come!

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I bought a Mezger for the replacement car... Nothing delicate hanging down low like the 996na. For this 996na rebuild I will use s 1/2" pan extension which will make the oil pan cover lower than the water hose. I will also be sure to use a factory "spring" clamp and not a worm clamp like the one that was damaged. Then a factory skid plate.

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There are threads that discuss the easiest way to get the AC bolt out.

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Yeah, taking a break right now, but I'm thinking explosives might be in order...

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I know the feeling. When I drop mine to do the chain guide pads, that will be the first bolt I go after.

I found I could place a flashlight on the cylinder head from the front and it would shine right on that bolt. Then, a little mirror work and I was in!

Heading to Harbor Freight for a couple of short extensions and a mirror... Thanks

If I recall correctly, a 1/4� ratchet with a short extension (3�-ish) makes short work of that bolt once you take out the temp sensor and grommet. You can do it by feel.

Use a crows foot, an extension-universal-extension and it will work. Once you get a mirror position and figure out the angle you'll be able to do it with your eyes closed...Lower the engine a few inches too.

Lowering the engine a few inches is a great suggestion! Even so, I think I removed mine before lowering the engine - it really isn't that difficult. It is however, slow and annoying! Re-connecting the hard line to the clutch slave cylinder is more difficult and annoying by far (at least it was for me...). Good luck, and take your time - you'll get it

I left my hard lines attached and just hung the CSC.

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Yeah, I knew that's how many people do it but I rolled the dice on the hard line. My logic was, that it was only one nut as opposed to two, and I wouldn't have to deal with aligning the slave cylinder afterward (it seems like many folks have problems with that). In hindsight, while I didn't have any problems aligning the slave cylinder, getting that nut to thread in with the hard-line attached was a bitch!

So the steps so far are: 1) Pop open front/rear bonnets and roll down side glass slightly before unhooking battery. Also, pull on E-brake to keep axel shafts from turning during disassembly. 2) Either unhook and remove rearmost undertray and cross bracing bolt, or make accommodation for thier removal once in the air (as the lift pad may cover). 3) Use a T-20 to loosen the tailight mount and pull light housing straight backwards. Unclip connector and stow out of harms way. 4) Unscrew bumper cover (phillips or torque bit) at top reinforcement plate; bottom attached to heat shield; sides attached to heat shield and one inside fender well. 5) Use a 6mm hex to remove bumperettes. These can be reached by prying off the cap at the bottom of the bumperette. Loosen the bolt and rotate the bumperette from the bottom to up to remove. 6) Remove bumper cover and be ready to catch it as it will be restrained by a small wiring harness. Disconnect and stow out of harms way. 7) Remove side skirts/heat shields. Stow out of harms way. 8) Unscrew clamp on throttle body. Use a 10mm socket to remove air cleaner retaining bolt. Remove housing and stow out of harms way.

9) Suck out petosin from power steering pump (I used a vacuum brake bleeder). Remove 10mm mounting bolt. Using a flat-blade screwdriver, pry/twist the plastic collar at the reservoir's base approx 1/4 turn CCW and pull the reservoir out. 10) Then suck the rest of the petosin out of the pump housing; then plug with toweling. 11) Using a set of two 19mm end wrenches; and then a set of two 15mm wrenches, unscrew the power steering fittings. Pay attention to the weird little internal clips/collars... They look important! Remove and stor in a safe place. ?(I don't really understand what these do)? ...perhaps I'll figure it out before re-assembly.

"Pay attention to the weird little internal clips/collars... " IIRC, they prevent the couplings from coming off end of the hose.

12) Make sure batt is disconnected. Use a 13mm socket to unbolt the pos terminal next to PS reservoir housing. 13) Unhook various vacuum fittings. Most of these quick disconnect by removing a cir-clip then prying down on the inner sleeve; push/pull to disconnect. Re-install c-clip so it doesn't get lost. 14) Mark and disconnect O2 sensors by prying up on the connector lock with a flat-blade screwdriver.

15) Unhook the engine wiring harness by twisting the connectors 1/4 turn CCW, then pull apart. 16)Now is a good time to empty the coolant. Expect several gallons, so have a couple of buckets handy. (unless, like me you cooked your motor by letting your coolant all drain out). Also remember that coolant is sweet and your animals will drink it; killing them... so take precautions! I unclamped the engine--->underbody pipe connections to drain my remaining fluid: 17) Now is as good a time as ever to drain your oil. Expect about 2 gallons. (I on the other hand drained several gallons of a nasty oil/coolant mix. No worries about the animals drinking that gunk!) 18) Unbolt the A/C pump, paying attention to finding the "hidden bolt"... This is TBA as I have yet to find it. In the meantime I will work on developing my Superman X-ray vision, Plastigirl flexibility and my Spidy senses. It is said to be here: BTW: What is a shade-tree mechanic supposed to do in the "Fall"? All of the leaves are pretty though.

At this point, the car looks like this: It's now time to reposition my lift pads, disconnect the under-tray and cross brace so that I can work on removing the shift cables/linkages/reverse light plug/clutch slave and then move onto removing the rear axle cross bracing/reinforcement and sway bar. Also, ...notice the mouse nest in the rear tail light housing, and in one of the previous pics, on top of the motor. There is something "special" about country living...

The hidden bolt is accessed through the air temp sensor location.

Success!! Once the mystery bolt (from the a/c pump) was out, the rest was easy! Just 4 bolts and raise the body off the motor. Thx for the suggestions on the a/c pump bolt..."Remove the air temp sensor and you've got a straighter shot at it"... Thanks 808bill. Also, I removed the throttle body and t-tube which allowed me to get a finger on and stabilize the socket while I reefed on it as the bolt was in poor shape from the previous disassembly... This was the hardest part of the entire process. Thx for all of your suggestions. Pics to follow.

Yes for me too. The AC line would not allow a socket to seat on my bolt. Then I thought of trying the crow foot...Worked like a charm! I sure wish I had a lift!

Phil had asked me to share a pic of the temp sensor and A/C compressor bolt: This is a view of the temp sensor. You just pull it straight up. Then you can slide the rubber grommet out of the way to allow for a little better angle on the rear A/C bolt. Then a look at the back of the A/C compressor. This is the set-up that got it done for me:

This is why you can't just use a straight extension; the hard line gets into the way and you just bugger up the bolt head: Worst of all, if you (or the previous mechanics) mess up the bolt head then you can't replace it without discharging your A/C system as it hits the hard line.

And yes, there is a squirrel's nest under my intake... And yes, he chewed into my + batt cable. ...I'm so going to catch one of these on fire someday....

Ok, so back to the steps: 19) Remove rear wheels. Be sure to separate them with wood slats or cardboard as the back of the rim on top will contact and scratch the front of the adjacent rim below. 20) Split the throttle cable (if it's a mechanical cable). 21) Remove various crossbraces. 22) Remove two 6mm hex bolts from clutch slave cyld and slide it forward, out of the bellhousing. 23) Remove axle bolts. 24) make sure that both the motor and transmission are supported. Remove the 2 trans mount bolts and 2 engine mount nuts. ...then raise the body off the engine!

Great Pics of the temp sensor removal and rear A/C bolt - Thanks - and +1 one the lift!!

Now the task of disassembling the admirable packaging/layering of the various accessory systems. I am convinced of an analogy: "if the rest of the world were to build a clock, it would be a sundial... simple and easy to maintain. If Porsche were to build a clock, it would resemble a Rolex... layers of gears and cogs... fabulous, yet exceedingly complex". I'm unsure whether I should be impressed, ...or worried about the reassembly! This is the layout of the Air-oil separator system: Uh oh, water is not supposed to be in here!:

I'm finally down to a bare block. All of the accessory components, hoses, wires and bolts are labeled and boxed up. Now down to the actual fun part of the engine tear down, failure forensics and planning the build(s). I had previously purchased a core motor with the plan of using the broken short-block (rod bolt failure) as a core for a new factory short-block. I believe it costs in the $5K - $5.5K range and will include the latest update to the IMS bearing (997 style). I am unsure if it comes with a new oil pump. My plan was to hopefully have enough parts to salvage a nice OEM build for the cabriolet and then also have a usable core for a build for my trackday car. The prospect of 2 usable motors is not looking real good right now. Even if the overheated motor's short block can be resleeved (oversize to a 3.8 + Carillo rods was the plan), it is likely that the heads are cracked and I don't think that welding and re-installing seats would work reliably on a motor geared for track service. Cross my fingers!

I have a 2000 3.4 block in the garage (d-chunk failure), if you want to add to your collection.

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I wasn't expecting this. Intake valves tangled up in the intake port... A busted intake valve spring and pieces of the hydraulic lifter spread across the valve cover. Looks like I'll need another head for sure. Un sure if LN Nickie's will bridge the gap of the broken cyldr wall. Not looking good for an OEM rebuild + a second track-day motor. Pics to follow as cell won't post.

It's odd that that lifter has wear and stays depressed. The valve spring looks a little short. Now that's not good. Looking even worse. I'm not sure that a new set of Nickies can cure this! The culprit. I wonder if this is on LN's list of the 25 common M96 failures... It seems that I'm going to have to rethink my options on putting together 2 motors.... It'll be lucky if I can source enough rebuild-able parts to put together one. I will need a #1-3 bank head and lifter tray for sure. I have the block stripped now and it will do as a core for the factory shortblock. I'll look into it on Monday:

Thanks for posting, sorry for the results...

Looks like a cool wine bottle holder or table now.

Ha! My shop doubles as an amateur winery... I bet I could make that bottle rack idea work! Cheers!!

What about the LN Nickies, can that solve the D-Chunk failure? Or how does it work? Do they insert a "sleeve" where the old wall was?

It's a whole new sleeve , the old one will be machines out so you should be ok, the head might be able to be saved also valve seats can be replaced and the chamber can be ground and welded back if you go to a good head place !

The cldr is broken out all the way down to, but not into the block housing (I think). I wonder if the block is salvageable with the new LN liner?

No problem re-sleaving that block, and I have seen worse heads than that welded up and repaired

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So besides nickies and headwork, what is the expensive items for rebuild like this?

A quick list. Connecting Rods, $ 1800.00, Main and rod bearings, $500.00,Lifters$350.00, Lifter carriers, $1400.00, Timing chains and guides, $500.00, Head Bolts $250.00,Oil Pump $500.00, Gasket set $475.00, MIsc $400.00. If it is purely a street car you can forgo the rods and just use ARP rod bolts but if it is a Variocam Plus engine the intake lifters are $250.00 a pop rather than $25.00. Also factor in new valve springs and keepers and valve seats as it looks like this particular failer was due to a broken valve spring or a dropped valve seat..

What is your source for those $-quotes? OEM Porsche main+rod bearings are $160 together ( https://www.design911.co.uk/fu/prod3...r--996---2001/ and https://www.design911.co.uk/fu/prod3..._99610312162/a ) and those other quotes seem on the high side as well.

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Why new rods? Are the existing one bent? Curious what the lifter carrier is and why it's 1400! Also what about balancing, is this something that needs to done on these engines after new pistons and/or rods?

Now cost analysis for the first engine (street car) is pretty simple: approx 5500.00 for a factory shortblock; (I have a separate core). I believe it includes chain guides and perhaps an oil pump. Then rebuild 2 heads including new guides, exhaust valves and springs, vario-cam chain guides, various gaskets/seals, air-oil separator, oil cooler, new water hoses, new vacuum hoses, belts, water pump, rebuild alternator. The fun part will be the track-day motor: If the block can be resleeved, then enlarge to 3.8. Forged rods and CARR or ARP bolts will help with unforseen over-rev's. Heads rebuilt with some clean up in the pocket and new (upgraded if available) valve springs will also add some protection against a "money shift". Still questions on: Bearing clearances? Maximum CR (track gas). And of course your mind wonders about any further "improvements" that you can try: A lot will depend on if a 1999 ECU can be reflashed. Questions come up about induction: a) Is there a slightly larger intake runner available? perhaps from a 3.6 model that will be better suited to a 3.8? ...(10% increase in displacement) b) Is there a larger throttle body available for a non-E-gas engine? Or, can the GT3 E-gas throttle body be modified to a mechanical linkage? (+ appropriately sized IPD plenum). Rev limit: Are solid lifters, or shim under bucket lifters and appropriate springs available? If so, can a service like Web Camshafts help the cam profile without ruining the mid range? At what RPM does the crankshaft turn into a noodle, flex and take out your rear main-seal? (I had read about someone increasing the rear main bearing size to help carry the load; real? Or, urban legend?) Oiling system: Will the oiling system accommodate any higher revs... or will it just puke out more oil? Do I purchase the Porsche motorsports AOS ($1000.00)? Or, can I just run a separate catch-can inbetween the AOS and the intake? Will do a sump extension/baffel and probably still an accusump. I currently have problems with the 1/2" extension hanging up when pulling off of my trailer. I understand that I'll need a 2" sump extension if I run slicks? Smaller front pulley to keep the water pump from cavatating/power steering from boiling. Lightweight flywheel? it sounds good... however, when you take away the dual mass flywheel, do you also need to then add a vibration damper to the front pulley? Does anyone make one? It's beginning to sound expensive... Let's just take one engine at a time and get the street car up and running again! Hey user 63031: My local dealer just quoted me $6726.52 for the shortblock... I thought that I read online that they were going for approx $5500.00. With your network, do you have any ideas of where else I should try?

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We have additional processes to save even blocks that have damage below the water jacket from something like a crank or rod failure. Adds some cost, but well worth it on a high cost core like an M97.01 or M97.21/22.

You should t need rods and I have a spare lifter housing but I'm in uk I'm sure someone can donate one!!

So why are you buying a shortblock? Why not just send in the existing one to LN and do the nickies? Similar cost? Or is there something I not getting...