22 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
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Discussion summary
YOUR RESEARCHRebuild/overhaul or not
Reported or suspected cause
rails since he has seen catastrophic failures
Reported cause
No successful repair reported for this finding.
1
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0
Suspected cause
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Reported fixes
Read evidence and context
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Discussions that report identifying a cause
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Reported cause · Original poster
The mechanic was concerned that it was the rails since he has seen catastrophic failures before).
Leading evidence: 'rails since he has seen catastrophic failures' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'rails since he has seen catastrophic failures' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Install original x51 baffle used way too much sealant' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Install original x51 baffle used way too much sealant
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
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Unsuccessful attempts
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Performed · outcome unconfirmed
Whoever installed the original X51 baffle used way too much sealant.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Performed · outcome unconfirmed
I used the sealant that came with the deep sump kit in the amount recommend in threads on this forum, which is a very thin coat on the sealing surface.
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Performed · outcome unconfirmed
Whoever installed the original X51 baffle used way too much sealant.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Suggestion
Make an informed decision after that (but replace the IMSB while you're in there)
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Performed · outcome unconfirmed
I used the sealant that came with the deep sump kit in the amount recommend in threads on this forum, which is a very thin coat on the sealing surface.
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22 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Generation: 20261026T113718Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Hi,
My car is a 1999 3.4 with 100k miles (5 chain).
For the last oil changes I have seen a bunch of black and brown plastic debris, I finally decided to have the wear pads changed out. This would solve the problem with the brown plastic debris.
However, the mechanic said he was worried about the large amount of black plastic debris as well and suspect it's the chain guide for the "IMS chain", so not the variocam wear pads. Unfortunately replacing these requires the engine to be split and it's a lot of work.
He said he had seen a few cases where this could lead to a catastrophic engine failure. (not sure if the chain guide it self wears out or if the black plastic bits get stuck in the chain and causes engine to fail).
Car runs OK, nothing obvious that is bad. The mechanic thought he heard a little rattle that could have been chain related. The cam deviation is within spec but on the absolute high side.
Could it be anything else than the IMS guide?
A few options:
1. Put in new oil and ignore all of this
This might lead to a catastrophic failure in the future that is very expensive to recover from.
Or the car might live until it get's rear ended or stolen or I sell it.
2. Pull the RMS and peak at the guide
Might tell us if it's this guide or not.
3. Engine rebuild/overhaul
Split the case and replace all the worn guides/chains and might as well do bearings.
Wouldn't address the bores/pistons/rod bolts (unless they look bad)
4. Do a LN Rebuild
Not sure how I would be able to finance this as a moment. Would much rather save up a few for some time and do a FSI track build in a couple of years.
The shop has a good reputation and only does Porsche work. They do a couple of engine rebuilds a year.
Any comments?
Gather as much information as possible about the current condition of the chain guides and scope the bores for evidence of scoring (if any). Make an informed decision after that (but replace the IMSB while you're in there)
If it does turn out to be chain guide, do the least amount of work (and preventive upgrades) necessary to get the engine in a state you're comfortable with. Decide what exactly this means to you ASAP - otherwise, you're going to "while you're in there" yourself to the poorhouse.
1 - You're asking all the right questions.
2 - If you're doing "proper maintenance" (i.e.: oil changes with good/proper oil type, UOA, water pump, AOS, Coolant etc.) 100k shouldn't be a "death sentence" - obviously there are all kinds of caveats to this, but the chances of a catastrophic failure "out of nowhere" are pretty slim IMO
3 - On the other hand of the motor is making weird noises (that you choose to ignore or chalk up to "that's normal for Porsche engines" or "that's just a sticky lifter") your fears may be warranted. Obviously not every noise means catastrophe, but don't ignore them. Track them down and fix them.
4 - If the FSI build program is a stretch financially perhaps the RND or LNE (kit program) is a better fit - in any case, once again you're asking the right questions, and planning accordingly.
All this ^^^ being said, if your chain tensioner pads are overly worn it's a good idea to address the problem (If the main one on the IMS chain catches on the chain and breaks, the engine is toast). A good start would be to read the cam deviations - if they're outside specified parameters, it's possible/likely that you're main tensioner pad may be overly worn as well (you've seen all that black debris). As you've surely surmised by now - there's no black or white answer. Ultimately you're going to have to make the call and live with it. Solid info is your friend...keeping reading and asking good questions.
The above photo is from the filter that I cut up a while ago.
The car is in a shop and they did drop the pan, waiting for them to send a photo. But they found a lot of plastic debris in the oil pan.
(So far the shop is doing everything right. The mechanic was concerned that it was the rails since he has seen catastrophic failures before).
Did they measure cam deviation? Looks like you need some new pads ASAP. I personally would not worry about the IMS pad since it is not replaceable without spending thousands of dollars.
This is what my sump cover plate looked like. My cam deviations are in spec, but just barely on bank 1. I plan on replacing the timing chain pads before I take it back on the track.
the plan was just to change the variocam pads but all that black is ims pad.
Shop says they have seen some catastrophic failures due to worn ims pads.
On the 3.4 a the variocam pads are still lots of work
I know! Whoever installed the original X51 baffle used way too much sealant. There were a couple of pieces that had separated and were stuck on the bottom of the oil pickup screen. I carefully cleaned everything up. I used the sealant that came with the deep sump kit in the amount recommend in threads on this forum, which is a very thin coat on the sealing surface. No oil leakage since installation.
On a side note, Bill, were you the person who wanted the original X51 baffle? I have it sitting in a box and I have no future plans for it.
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