996 Rebuild, Refresh or Something Else Needed?

I have a 90k 2000 996.1 6-speed that I am trying to determine how deep into the engine I need to get based on new discoveries (metal) in oil sump... Background Project began as IMS/RMS, Flywheel/Clutch project... effectively just dropping the tranny. Chose LN option, and then as part of pre-qual, discovered I had a cam deviation... so now dropping engine and tranny to replace wear items. At this point the plan is to fix deviation (cam to cam chains, guides/rails, tensioners, etc.). And "while I'm in there, take care of AOS, pumps, etc. Continuing along the LN process, I drop the oil sump to inspect oil and conduct cylinder borescope. In so doing, I find a penny sized non-ferrous metal object (picture below). After my freak-out subsided I sent my oil for analysis and reached out to LN, who said the particulates in my filter and oil were normal, the plastic bits were from the guides, and the large metal piece likely from manufacturing process that just recently broke off. Sent them borescope picks and no borescoring evident, so that was promising. And the Blackstone analysis came back "better than good". Prior to project, there was no indication of any problems other than the clutch and a subtle whining sound that would go away after car warmed up that folks suggested might be related to the throwout bearing, which I planned to replace. No knocking, no ticking, no rough idle, no start-up smoke or other symptoms that caused concern. Next Steps??? So now I am trying to decide how deep into the engine I need to go, or at least the key steps to follow to help me decide where I am safe to stop without incurring unnecessary "while I'm in there" costs. My primary concern is either tracking where that piece of metal came from and/or eliminating the possibility that it (or something else) might be set to do some harm. Thoughts?

I think once you get the cam covers off you'll be able to see if that's the top of a lifter. Would be surprised if it is since the engine sounds normal. From the other thread I don't see much else I would do, some things on there I wouldn't but that's me. It's possibly that piece has been in there for the past 20 years.

I don't think it's a reasoned argument. It's whether you view your purchase as a mistake now (detail and flip it) or at the other extreme as Jake Raby says you "love your car" enough for a ticket on his waiting list. I believe there are "in between" zones. Being in Australia where all 911s are viewed as special yes air cooled "more special" cars are still not an investment category. For me in between is an LN Nickasil cylinder elective complete rebuild (JR points out even Nickies may be banned environmentally), and IMS solution etc. I'm not contemplating resale and getting money back, but view the 996 as a better authentic entry into Porsche than front engine 924/944/968/928 or SUV, or new/newer finance and loans. My attempts at other sport cars from TR7 to Mercedes 380 SL, have not succeeded. My other keepers are sedans. My 996 has been a very straight forward fun car. I want to electively rebuild and stock critical spares as they get NLA etc. (now is a critical time) -make it a keeper. The 996 is a practical Porsche in reality, but decisions are personal about how you view the car. How far you want to go? how long do you want to own it?

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That sounds sensible as a minimum baseline. Thanks.

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Thanks for responding. On part 1 of your response, I may have inadvertently provoked a philosophical response because of how I titled my thread. I love my car, intend to keep it, and intend to keep it strong and healthy. As a newbie into this world I was merely looking for practical advice on my particular situation. Not sure that going with an LN Nickie's overhaul applies in my case if the engine is healthy (bores, pistons, etc.). Sure, doing that would be an "upgrade" of sorts with additional performance opportunities, but I'm not tracking this car or looking for more than came stock. Your closing comment is spot on with my scenario. I don't plan to sell (as far as I can see), I love to tinker and maintain things to keep them performing well (if not slight better), but nothing over the top. I also don't feel like I have to do it all at once and since I plan on doing all the work myself, I'm not worrying about the additional labor costs to go in there twice. My wain worry is eliminating the concerning source/impact of the metal object, and doing as much that makes sense on an otherwise well performing engine without having to drop the engine for another 3 years or 25k miles. Any additional thoughts on how to assess how deep into the engine to go or the things I should minimally do to eliminate concerns that might arise over the next few years?

The only way to get �deep into the engine� is to drop it and do an invasive recon mission. If you�ve got some space and don�t drive it during the winter months, this is a nice way to go, and a valuable learning experience. If you just want to check out the cylinders, a bore scope can get you there. It seems like you�ve got a pretty good handle on maintenance and general needs. Very few parts are truly NLA at this point (you can always go the used route) and now that the 996 fits into the �Porsche Classic� category more should become available (albeit at a price�). Just remember that the suspension is a big part of the charm and abilities of these cars� good luck 👍

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Thanks. On suspension, that will likely be the next project. With the wheels and bumper off, the rear is screaming for attention. The previous owner put 19" wheels on, but the suspension seems all stock / original. What would you suggest to return it to its glory for street use?

From your initial post, it sounds like you've already confirmed that you don't need to worry about the bits you found. Why not do the tensioners, install the IMS solution, AOS, water pump, maybe injectors and plugs/coils, reinstall the engine and enjoy it? Since you have the sump off, probably a good idea to borescope it and hopefully find you don't have bore scoring.

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for your peace of mind, this was found in my sump a while back and it was determined to be part of the manufacturing process.

Wonder where the hell it came from in the manufacturing process.

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he already mentioned borescoping happened and no scoring was found.

The explanation given to me was that Porsche has a terrible housekeeping policy. For mine, the theory is that something was drilled out and a piece was stuck to the useable part. When the engine was assembled, this shaving was then displaced with whatever occupied that hole, falling into the sump. Unfortunately I'm new to these cars and engines so I wouldn't begin to guess there that hole would be located.

That's the end layer of a drilled hole, the piece that breaks off when the drill passes through the part. It's absurd that these get left inside the engine.

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Awesome!

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Those thin aluminum parts look to me like machining errors that can happen occasionally, they could be flash from the casting that is supposed to be cleanly cut away via CNC, however a small % of them can bend away from the tooling rather than be cleanly cut away (more likely if the engine was made at the end of the tooling life before its swapped for new/sharper tools), they can hang on for a short or long time then eventually break off and enter the oil

Better the sump than somewhere else.

Thanks all for the tips and advice. I've jumped into the project with the intention of not going much further than the cams and lifters unless I find something that begs going deeper. Background, update and pictures below: Project Plan... - Timing: fix cam deviation, replace all accessible timing/chain rails, cam to cam chains, all tensioners - Engine: Replace and install LN IMSB, RMS, check/clean lifters - Mounts: replace engine mounts (leaking) and transmission mount (showing cracks) - Preventive Items: AOS, water pump, oil cooler - 90k Items: Clutch, Flywheel, Fuel Filter, plugs, ignition coils, tubes, serpentine belt, fluids, injector check and cleaning - Nominal Upgrades: LN Oil pump drive, pressure relief valve, low temp thermostat, magnetic drain plug, R&S coolant connector Project Status... - dropped engine and disassembled all bolt-ons, cables and tubes.Engine quite dirty from leaks and even discovered a nest! - Aside from leaks, found consider carbon build-up in manifolds and on the top of some of the heads. - Redid cylinder borescope with engine out and no issues. Performed leak down test to complement borescope: Bank one ranged from 2-6% loss and Bank 2 from 6-9% loss. - Opened Bank 1 cam cover and removed cams, guides/rails, lifters and lifter tray. - Found expected pitting and degradation on guides and to lesser extent on long rails. - Lifters seem in good condition and not the source of mystery metal object that some suggested (pending getting into bank 2). Question: - Anything in the above or pictures below that prompt concerns or questions I'm not already addressing? - Does it still seem reasonable to not go deeper into the engine? Pictures...

I would say u went far enough. Hopefully u put a uaos back in for but if u didnt just check it every oil change.

Great job! Thx for posting the pics too. Seems many engine builders for these m9x engines rec replacing injectors over cleaning. I'm not sure why. But I would consider that. I'd second the UAOS and even the IMS solution (if budget allows). Interested to see before/after cam deviation #s.

Cant tell if you did it, but uaos and oil cooler since the engine is down. In fact, go with the uaos track version and you never have to worry about the effects on your engine if you accidentally overfill the oil.

Oooh, this looks like fun! I too am doing an LN Engineering bore up rebuild. In fact, LNE just called me to tell me that the engine is READY! But the connecting rods are on backorder. Ugh. I'll be documenting the process on my channel. I already swapped the suspension with Koni so check that out.

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Thanks. I am absolutely putting in a new AOS. Were you making another suggestion with "uaos", possibly ultimate AOS? Not looking to make that investment, but checking at oil change intervals is sensible.

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I seen mixed reviews as well on injectors. I decided to check impedance and send to witchunter. I considered both UAOS and IMS solution. Since I am having to do more than I bargained for so soon after purchasing, thought this was a solid baseline start. Will share before/after data in 30 days... at least that's the plan :-)

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Hi Yogi. Cool to see you post a comment as I've watched your videos as part of my "996 orientation" for this project. I'm glad I don't have to overhaul my engine as that's beyond my budget / capabilities (for now)... but sure is fun watching you get it done. Looking forward to your next video.

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Not there yet, but replacing with stock AOS. I'm not tracking this car or putting into extreme conditions. I do agree that the UAOS has both convenience and performance upgrades, it's not in my economic model with all the other work I'm doing (at this time).

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The UAOS not only has convenience and performance advantages, but also safety and economic advantages. It has a built in warning system to illuminate an integral dash warning, ( for safety reasons) , and compared to replacing the factory AOS every 3-4 years as advised by high caliber Specialist 996 shops, will be cost/labor$$ effective....as well as the convenience and performance advantages. Just sayin

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You're killing me with common sense :-) You make a great argument. It's just as compelling, if not more so than the one I received (maybe from you on my original thread) regarding my choice to go with the IMSB retrofit vs the solution. As a first timer, in the fullest sense of the phrase (new to P-car, new to auto DIY, new to convincing my wife to buy a fun car) I taking the path of least resistance to a happy home. While I'm reaping the savings of doing all the work myself, those savings are all going to the tools to do the work... I literally had nothing. The quicker I get the car to a sound baseline and having her enjoy it with me on the Cali coastal highways, the easier it will be to go deeper into the next project. In a few years, I'll happily get the UOAS and LN Solution after having earned the trust and admiration of my wife in my newfound mechanical prowess... with the help of this community of course!

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I hear ya bro, keep strokin it !! The Wifie will love the new you !!! Or else y'all need to have a serious talk ...

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this! Don�t overthink it!

Happy Fathers Day to all the dads out there. While I was waiting for parts to come in to fix cam timing, I began cleaning away. When I inspected the lifters, all look good cosmetically. When they came out of their cradle, they all were stiff as you would expect, except for one or two, but generally not squishy. At first, doing this for the first time, I thought that was a bad thing until reading up on it. As I understand it now, they should be stiff coming out of the engine and weep over time when outside of a pressurized environment. So when they remained "stuck" after being out for 2 weeks, I began to wonder if they were that way for all the wrong reasons. I worked them over a couple of days while I did other work, getting the old oil (very dirty) out of them. I gave them a hot bath in engine oil as some threads suggested to get the air out of them and to replenish with new oil. I was worried after a day that I should have left well enough alone as they were all still very pliable, so I did a repeat hot soak, depressing them each several times. After another 24 hours there's a huge noticeable difference. They're still not quite there yet, but maybe it's just a matter of time. The idea being if any cannot accept/retain the new oil, I'll replace them. I know that once in the car, if not damaged, they'll regain their appropriate state, but I want to make sure before they go back in that they have a likelihood of doing so. How long does it normally take for them to be soaking in oil before I can properly check them? How much play should they have / not have? If for argument sake, one or two are bad, do I need to replace the entire bank of them, all 4 associated with the respective cylinder, or just the bad one? I found the OEM INAs on eEuroparts for 16.97ea. roughly $400 for all 24, which isn't bad, but I'm trying to keep costs down on this project (without doing something stupid along the way).

Project update: Replaced a lifters with new, set timing and everything looks good. However, I'm now getting leakage out of the exhaust (leak down test with engine out) on multiple cylinders. I've confirmed cams/lobes in correct orientation and at TDC when testing cylinder. Leakdown check was good before disassembly and valves appear closed, with no light creeping through with borescope light (that I can see). Any ideas on how to troubleshoot. I hate to now go deeper after having gone this deep just to confirm that metal piece was not indicative of a major problem.

So just a short 13 months later, I'm finally nearing project completion. Had to hit the pause button with life's priorities, but got back in the game a few months ago and can see the light. I will post more pictures when done, but here's a rundown of the work done followed by some pictures at the end... Transmission (DIY)... DONE - Flywheel (LUK) - Clutch Kit (Sachs) - Clutch Release Lever (Porsche) - New bolts - Oil (Porsche) - Pivot Ball (Porsche) - Retaining Spring (Porsche) - Throwout bearing (Porsche) - Transmission Mount (Lemfoerder) IMS / RMS (DIY)... DONE - IMS (LN Dual Row Retrofit) - RMS (Porsche) CYLINDER HEAD / TIMING (DIY)... DONE - All new lifters - 2 Cam to Cam chains (Porsche) - 3 Chain tensioners (Porsche) - Variocam Pads (Porsche) - New head bolts CYLINDER HEAD (Len Hoffman)... DONE - Exhaust Seat replacement (couple) - Valve and Seat Grinding - Head surfacing - All New springs UPGRADES (DIY)... DONE - 997 Coils (Beru) - Coolant Connector (Rauch & Spiegel) - Low Temp Thermostat (LN) - Magnetic oil drain plug (LEAVING NOW) - Oil pump hex drive (LN) - Pressure relief upgrade (LN) REPLACEMENT / MAINTENANCE ITEMS (DIY) - AOS (Porsche) - Engine Mounts (Rein) - Fuel Filter (Mahle) - Oil Cooler (Behr) - Seal replacements (Porsche / Victor Reinz) - Spark Plugs (Beru) - Spark Plug Tubes (Porsche) - Water Pump (Pierburg) OTHER... DONE - Fuel Injector test/cleaning/refresh (WitchHunter) - Engine bay cleaning MODIFICATION... IN PROCESS - Fister style Muffler Mod (Meineke) - Cerakote entire exhaust... headers to tips (DIY) ENGINE/TRANSMISSION INSTALL... NEXT WEEKEND!!! - Fluids (Motul Oil, Coolant, Pentosin) - Coolant Reservoir Cap (Porsche) - Serpentine Belt (Continental)

If you can, change the Oil-Spike (Temp/Level sensor) and the oil pressure sender and the starter.. I didn't do the starter.. and I will be ,, but in the car.. Cheers fun to watch your project...

Wow! Quite a journey� Looks like you addressed just about everything on the top end. I didn�t notice whether you went with the IMS Solution, but I hope so. I bet you can�t wait to drive it!!! Good luck 😃👍

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Congrats! Looks great. What was the resolution to the exhaust leakage?

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Funny, all this time, no one had recommended those. For the sake of getting much more done than I ever planned, I'll likely proceed with what I have... so I can join you in misery sometime in the future :-)

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Great question. That's why I went into the heads to begin with. I have a couple of newbie theories: (1) and the most likely, when I was cleaning the ports with the heads on, gunk drop down preventing the valves from closing, and (2) two of the seats required replacing and as a precaution I had the guides replaced (all on the exhaust side)... or it was a combination of these. I had thought I did something stupid in turning the engine in reverse and bending valves, but they were all good and could be returned to spec. I failed to mention earlier that this was also one of the reasons I had to step away from this project to regroup: After having the leakage problem and thinking I bent the valves I added the head job as part of my DIY development... biggest regret of this project. I tried to do the valve job myself using Neway cutters and valve refacer. All was going well until it wasn't. I couldn't get consistent measurements or seating on a couple of valves which was explained ultimately having to get a couple of exhaust seats fixed. I attempted a hybrid job with a machine shop (guide replacement and head surfacing/cleaning) with me doing the valve job as part of my DIY development. This is when some back and forth with some folks on Renntech really helped me out, resulting in me sending the heads to Len Hoffman... which I should have done to begin with. But this too was part of my education! As many have suggested, Len is phenomenal, delivers quality work on time, no nonsense.

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This was another big debate... or should I say conflict with myself that many here attempted to guide me. I decided not to go with the IMS Solution, so I know I simultaneously decided to go back in there some years later (if I still have the car). I don't have regret on this as I'll happily go back in with my newfound capabilities, and in terms of already doing more than I had planned or thought I needed, net net I'm feeling good about it. Considering how I know so much more about auditing (oil analysis) and DIY on these engines and not having to take things to the shop (unless it's way beyond me) I'm ahead of the game... at least that's my rationalization. Oh... and not having my wife think I've gone too way over budget was a big factor!

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Thanks! I'm always learning about these engines so any nuggets of knowledge are valuable. Seems we learn more from our mistakes. I've been guilty of plenty! And I've accidentally rotated the engine backwards as well so I share your oh sh*t moment. Glad you were able to figure it all out and get it sorted.

I do a lot of things myself including lapping valves and seats on air cooled heads. But I would stop at professionally doing a valve job on a 996/7 engine. At some point, you have to let someone else be the expert at something. My 997 heads are with a local machine shop right now. It's been 2 months.

Project Update... good news, bad news. Good news: Got the car up and running. Felt great completing the project, and getting the car on the road with nothing "blowing up"! Bad news: durametric telling me a slightly different story about my results. Throwing o2 sensor fault codes ahead of cat P0150 (bank 2) and P0130 (bank 1). More concerning is my timing being off: Bank 1 -4.97, while Bank 2 is 0.00. I had taken the car for a few short drives to ensure fluid levels, oil pressure, etc. I put the durametric on it after a 30-minute drive at idle. On background, I changed all the IMSB/RMS, tensioners, chain guides, cam-to-cam chains, lifters, springs. Before the work my deviations were Bank 1 (-10.44) and bank 2 (-5.64). Don't know if it's coincidence or means something that the difference between the two banks is roughly the same before/after, and bank 1 continues to be the only/bigger problem. I find it interesting that I could even get bank 2 to perfect 0.00. Questions: - What do you make of the before/after values? - Are there other diagnostics I should run before I go back in to better ID what's going on (timing and/or cats)? - Assuming I have to go back in, what's the least invasive way for me to get access to bank 1 without repeating my complete engine/transmission out procedure? - Once in there, beyond timing procedure, is there anything I should assess more specifically? - If I adjust timing on Bank 1, I assume I have to repeat the timing procedure for bank 2, correct?

U can cheat the timing gear on the bad bank. Most likely its due to long chain wear and nothing u did. Honestly its within spec and i would leave it. Pm @Porschetech3 for the how to. He will know which way to cheat the gear and the risks involved. When i did my car it was -6 and -3 and after the work it went to -2.5 and +.5 so your values r inline with others. U almost never get the side thats way out of wack to 0.

Nice work. Long project, but well worth it I'm sure.

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Thanks for the input. I'll reach out for the cheat-gear process, but not sure I will want to entertain getting "creative". I wasn't necessarily expecting to be at 0 on either side... just not expecting to be one degree from outer end of spec on either bank after all this work. What I hear you indirectly saying is that I could possibly go back in and re-time and still end up with same/similar results without addressing the long chain. Could it be something else?

If u did everything correctly and u used the tool to time the gear then it wont change. Most likely the issue is the slack/wear in the chain. Its posible u r a tooth off on the variocam but i dont think so. To cheat the gear u just pull the scavange pump, loosen the tensioner, loosen the 4 bolts on the gear and rotate (not sure the direction). U only want to go a few degrees. U may have to do this process a couple times to get it correct. Its difficult because u will want to do it with the motor in the car so u dont have to pull it several times. The clearences for the scavange pump r very tight but it can be done.

So my local guy, finds them all the time and said its a milling process from a bore end cut that Porsche says doesn't hurt anything since its in the sump and cant get out.. This is way more common than folks realize not just Porsche..