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THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHTiming chain on high mileage engines
Leading reported evidence
Use roller chain, and the later
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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Discussions that performed work without a confirmed outcome
1
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Performed · outcome unconfirmed
I thought the older cars used a roller chain, and the later used a tooth style.
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Suggestion
The later style fails differently than the early style, as they will typically just fill the oil with debris that takes out other parts within the engine before they snap.
Leading evidence: 'Use roller chain, and the later' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Fill oil' (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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Performed · outcome unconfirmed
I thought the older cars used a roller chain, and the later used a tooth style.
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.
Discussions that contain suggestions
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Suggestion
The later style fails differently than the early style, as they will typically just fill the oil with debris that takes out other parts within the engine before they snap.
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.
Discussions that contain suggestions
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Suggestion
If so, it is yet another point in favor of the more frequent LN-recommended service interval.
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Discussions that contain suggestions
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Suggestion
I wonder if timing chain failure is aggravated by the extended service interval Porsche recommends for oil changes(15K miles) ?
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
Fill oil
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
The later style fails differently than the early style, as they will typically just fill the oil with debris that takes out other parts within the engine before they snap.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
11 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T165820Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
After reading a thread on a high mileage engine blowing up due to the timing chain, I have to ask the question...Is the chain considered a maintenance item? Can it be replaced by the home mechanic?
I remember on my 944 I had to replace a plastic guide, is that same issue present on the M96?
I'm going on 165k miles on my 996 so if this is something I should be looking at I'd like to know!
Gents,
Here is an older thread on the same subject. Block needs to be removed to change chains and therefore it might as well get clutch etc etc.
As I understand there are also plastic chain guides that will wear over time and eventually fail.
https://rennlist.com/forums/996-foru...placement.html
Timing chains can fail at low mileage. I have caught a timing chain in the process of failure at 38,000miles while pre- qualifying for an IMS Solution job.
We developed master linked timing chains, and have a procedure to install these without engine disassembly. The original chains are constant, and have no master link. More and more people are opting for this to be done during our IMS Solution retrofit procedure.
While these failures are not viral, they make up about 10 of the failures we see per year. Often times these are misdiagnosed as some other failure, even an IMSB failure. This is because of the symptoms being similar to an IMSB failure.
A broken chain is one of the nastiest failures that can occur, its #2 in the damage department, only one upped by valve seat failure, in regard to how bad the collateral damage exists.
The original chains are made by Renold, and are not the quality of the Iwis chains.
Yes, for the IMS drive chain only. The later style fails differently than the early style, as they will typically just fill the oil with debris that takes out other parts within the engine before they snap. The early style won't do this, it just loses a roller, then snaps.
That said, these IMS drive chains are deep at the heart of the engine and cannot be accessed without full teardown. We see better service from the IMS drive chain, than the main timing chains that drive the cams, via the IMS. These are what I was referring too earlier in the thread. I'd only be concerned with these main chains, and on 5 chain engines I am more concern with the simplex chains that drive the intake cams, via the exhaust cams. These are the most probable for wear.
So in other words although this is a method of failure I probably shouldn't worry about it until it's time to rebuild the engine.
Since the block has to be opened up anyway I may as well go full-on rebuild at that point in time.
I wonder if timing chain failure is aggravated by the extended service interval Porsche recommends for oil changes(15K miles) ?
If so, it is yet another point in favor of the more frequent LN-recommended service interval. Cheap alternative to a chain failure !
