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THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCH996 Bearing Assemblies Shifting In Engine
Leading reported evidence
Run these engines
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1
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Suggestion · Original poster
Before I removed one bolt, a gentleman at a Porsche dealership whom I was discussing my 996 rebuild endeavour with alerted me to some problems I may encounter running these engines.
Leading evidence: 'Run these engines' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Run these engines' (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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Run these engines
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 · Original poster
Before I removed one bolt, a gentleman at a Porsche dealership whom I was discussing my 996 rebuild endeavour with alerted me to some problems I may encounter running these engines.
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.
2 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Pelican Parts: 1 discussions
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Generation: 20261027T140027Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Hello,
Just relaying an experience I have had over the last few months that I thought might be interesting. First time I ever posted anything on the internet so please bear with me, thanks in advance.
Well I have recently taken to rebuilding 996 engines for the Grand Am Koni Challenge Series. I have rebuilt five of them in relatively quick succession and have noticed something I'd like to share for what it is worth.
Before I removed one bolt, a gentleman at a Porsche dealership whom I was discussing my 996 rebuild endeavour with alerted me to some problems I may encounter running these engines. The rear main seal was one, lifters were another, and then he mentioned the possibility of the entire bearing assembly moving inside the case halves. I couldn't believe it but he said they had seen it at the dealership. I planted those seeds in my mind and proceeded to rebuild.
Well, after some rebuilds I got an engine back in which a vibration was reported. I received the engine sans flywheel and I noticed the crankshaft sensor had been cut by ostensibly the flywheel. Inspection of the rear main seal revealed a cranshaft that was not in the center! At that moment I recalled what I had been told and that was that.
Of course upon complete disassembly I found no witness marks to confirm that the bearing assembly had in fact moved. To make an otherwise long story short, the crankshaft broke at the number six rod journal. Broken over two thirds the circumference.
My theory is that the dealer thinks there is a problem with shifting bearing assemblies because they remove engines, see what I saw at first, and then ship them off to Porsche as cores--they don't ever take them apart at the dealer.
Do people really talk about a so called bearing assembly shifting problem? Just thought I'd put it out there. The flywheels are insanely heavey, even the Aasco ones. It was really built well I like to think like the others. I have built many Porsche engines, granted only five 996's, but a broken crank I've only seen once before from Porsche. Only 15 hours on the engine...anyway.
Thanks for reading. Sorry for the bad photo skills.
Welcome to the forum.
Definitely an interesting picture.
Personally, I don't think it is a case of the bearing assembly moving, but more of the fact that the crank, bearing cage, and case are not concentric to each other, unlike the older engines where the bearing journals were actually part of the case.
This is a source reference. Confirm exact model applicability in the original material.
