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Discussion summary
YOUR RESEARCHInteresting post about bore scoring and diagnosis
Reported or suspected cause
liberated silicon particles in cast aluminium cylinder linings
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Reported cause · Original poster
The root cause is liberated silicon particles in cast aluminium cylinder linings.
Repair /mitigation: older engines (pre‑2008/9) may be rebuilt
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Suggestion · Original poster
Repair/mitigation: older engines (pre‑2008/9) may be rebuilt with Nikasil-lined sleeves and other renovations; newer engines (post‑2008/9, e.g., 991) are generally more durable but require immediate repair if seized.
Leading evidence: 'liberated silicon particles in cast aluminium cylinder linings' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'liberated silicon particles in cast aluminium cylinder linings' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Repair /mitigation: older engines (pre‑2008/9) may be rebuilt' (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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I do enjoy seeing how many miles you can go on that engine as a testament to the 3.4 5 chain engines being ran hard.....
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Suspected cause
If bore scoring is caused by spontaneous combustion, at least I tried.
Repair /mitigation: older engines (pre‑2008/9) may be rebuilt
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Suggestion · Original poster
Repair/mitigation: older engines (pre‑2008/9) may be rebuilt with Nikasil-lined sleeves and other renovations; newer engines (post‑2008/9, e.g., 991) are generally more durable but require immediate repair if seized.
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Suggestion
The Mezger GT3 Cup engines used in Competition are suggested to be rebuilt every 50 hours....can they be ran longer?
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Repair /mitigation: older engines (pre‑2008/9) may be rebuilt
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Suggestion · Original poster
Repair/mitigation: older engines (pre‑2008/9) may be rebuilt with Nikasil-lined sleeves and other renovations; newer engines (post‑2008/9, e.g., 991) are generally more durable but require immediate repair if seized.
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Suggestion
And to add more detail to the mechanisms that effect Heat and Friction more on Bank 2 than Bank 1 is the fact that the water pump is located on the Bank 1 side and delivers the cooled water from the radiators directly to the lower cylinder side ( thrust side) of Bank 1 whereas to deliver the water to bank 2 it is channeled acrosss the top of the sump where it is splashed with the hottest oil coming off the main and rod bearings, then is delivered to the lower side of the cylinders where it absorbs more Heat, then finally to the top side of the Bank 2 cylinders ( thrust side) ...so the coolant has absorbed considerably more Heat by the time it reaches the area of Bank 2 that Scores first and
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Suggestion
So on both sides of the spectrum you have on one end testing oil analysis on every oil change and periodic Blow-by tessting, and on the other you have just drive the car without monitoring or testing anything, just wait until/if symptoms arise...
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Suggestion
But I am in favor of monitoring engine health through periodically testing Blow-by, and using oil analysis to monitor engine wear, or even if a racing engine it is common to test compression and leak-down frequently...
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Suggestion
But I am in favor of monitoring engine health through periodically testing Blow-by, and using oil analysis to monitor engine wear, or even if a racing engine it is common to test compression and leak-down frequently...
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Suggestion
So on both sides of the spectrum you have on one end testing oil analysis on every oil change and periodic Blow-by tessting, and on the other you have just drive the car without monitoring or testing anything, just wait until/if symptoms arise...
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Suggestion
But if the previous owned had accurately tested the Blow-by at WOT , the compression and leak down , Bore-Scoped it , tested oil pressure with 40wt at 90C and 4k RPM and documented all results and with pictures , then you did the same now, you would probably see a difference even if symptoms are not readily apparent ...
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Suggestion
Regarding AI, I today learned that if you have finished one query through AI, the next one, on a different topic must be started as a new dialog/query as otherwise all of the previous dialogue will be used/considered by AI to generate the response.
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.
26 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Generation: 20261026T130754Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
https://www.facebook.com/groups/591859944843493
Here is an AI summary
Bore scoring is described as a stochastic, hysteresis-driven catastrophe: it happens rapidly and unpredictably rather than as a slowly predictable wear process.
The root cause is liberated silicon particles in cast aluminium cylinder linings. Particle size, distribution, and bonding determine how and when they break free.
Lokasil: larger, variably bonded silicon particles; some are loosely held and can break free earlier, eventually producing a sudden �grit cascade� that scores the bore. Polishing marks can appear earlier but often aren�t dangerous.
Alusil: generally smaller, better-bonded silicon particles that break free less readily and usually cause less damage, so Alusil tends to last longer.
Thermal and casting-stress effects (uneven heating, thicker lower sections, slow shrinkage/stress relief) can reduce clearances over years and trigger sudden seizure-type catastrophes when pistons expand more than bores.
Oil analysis and additives cannot reliably predict or prevent these sudden failures; thicker oil and cooler coolant can help by keeping a thicker film so more particles are carried away.
Operating conditions: high torque at low revs thins the oil film and raises risk; high revs/track use often increase hydrodynamic pressure and are less damaging.
Repair/mitigation: older engines (pre‑2008/9) may be rebuilt with Nikasil-lined sleeves and other renovations; newer engines (post‑2008/9, e.g., 991) are generally more durable but require immediate repair if seized.
Final note: beware vested-interest advice pushing frequent oil analysis�such analyses won�t reliably prevent bore scoring.
Baz’s original M96 paper probably still can be had from his company website. You had to sign an NDA back a few years when he first published. He deep-dives the subject (and other M96 foibles) the AI summarizes. Not light reading, very sciency. This AI summary appears to confirm the long-held advisement to not lug a cold engine, Lokasil sucks, UOA isn’t ever telling the whole story and snake oil salesmen still sell snake oil, just “better” snake oil.
My critique/opinion on the subject matter using this summary as a guide...
" Particle size, distribution, and bonding determine how and when they break free."
I disagree that this is the root cause of Bore-Scoring on the M96/7 engines. My opinion is that Heat and Friction are the Root Cause...98% of all Bore-Scored M96/7 engines do so on Bank 2 and Cyl #6 is the most effected. Bank 1 has the same particle size , distribution, and bonding as bank 2 so that can't be the Root Cause....
Controlling the Heat and Friction by keeping the oil/coolant temperature lower and using friction reducing practices like good clean high viscous oil and friction reducing additive packages is the best defense of protecting against Bore-Scoring ...
" it happens rapidly and unpredictably rather than as a slowly predictable wear process."
The onset of Bore-Scoring may happen as rapidly as a Shotgun blast to the chest, but we have seen various stages from just a few scratches to mild scoring to catastrofic scoring and have seen engines live for tens of thousands of miles after the onset before it becomes a loud ticking or high oil consumption, or too much Blow-By to live with ( Catastrofic) ..
" Final note: beware vested-interest advice pushing frequent oil analysis—such analyses won’t reliably prevent bore scoring"
This is quite obvious to all Gearheads. Its like saying that testing compression and leak down tests will not prevent a burned valve..duh... But I am in favor of monitoring engine health through periodically testing Blow-by, and using oil analysis to monitor engine wear, or even if a racing engine it is common to test compression and leak-down frequently...
So on both sides of the spectrum you have on one end testing oil analysis on every oil change and periodic Blow-by tessting, and on the other you have just drive the car without monitoring or testing anything, just wait until/if symptoms arise... In the real world everyone will fall somewhere in between...
Yeah but when you say that particle size, distribution and bonding is the Root Cause, it contradicts the real worlds evidence that bank 1 has the same particle size distribution and bonding as bank 2 and it hardly ever fails, so that can't be the Root Cause.... It has to be Heat and Friction .....
That�s AI for ya�Its as bad or worse for medical advice (ie: you die instead of your car breaking). A.I. is only as good as the available data and the question(s) being asked - leave out relevant points and you�ll get back irrelevant/partial answers� User(s) Beware!
Deleted, as I was assuming instead of knowing.
Regarding AI, I today learned that if you have finished one query through AI, the next one, on a different topic must be started as a new dialog/query as otherwise all of the previous dialogue will be used/considered by AI to generate the response. The latter greatly increases the probability of AI hallucinating.
I can't see the facebook foo but what I'm collecting from here is that there is a failure scenario where catastrophic damage occurs very quickly. Okay. But anyone who has been following the topic has seen varying degrees of scoring across varying numbers of cylinders, which indicates to me that there is more than one failure scenario.
As for UOA there are many reasons to get it done, not just bore score testing.
Its alarming to me how many people I see use it regularly to ask it a question and then just take whatever it spits out as established fact, and then make decisions based on it. People are outsourcing their critical thinking, at a time when critical thinking in our society is critically low. In my humble opinion, using AI in this manner is just making people dumber.
But anyway, on the borescoring, I guess you might say that you shouldnt put all your trust in UOA to predict borescoring, or "trust but verify".
The movie Idiocracy is starting to look like a documentary.
Bore scoring?
I�ll continue to do everything that �some� have said helps prevent it. That includes getting UOA every oil change.
If bore scoring is caused by spontaneous combustion, at least I tried.
If you read that Objectively and Scientifically it is describing the mechanisms that effect the Heat and Friction of Bank 2 more than Bank 1 ...( not particle size, distribution, and bonding differences between Bank 2 and Bank 1 ) ...
And to add more detail to the mechanisms that effect Heat and Friction more on Bank 2 than Bank 1 is the fact that the water pump is located on the Bank 1 side and delivers the cooled water from the radiators directly to the lower cylinder side ( thrust side) of Bank 1 whereas to deliver the water to bank 2 it is channeled acrosss the top of the sump where it is splashed with the hottest oil coming off the main and rod bearings, then is delivered to the lower side of the cylinders where it absorbs more Heat, then finally to the top side of the Bank 2 cylinders ( thrust side) ...so the coolant has absorbed considerably more Heat by the time it reaches the area of Bank 2 that Scores first and foremost.....And to add to that is the Heat from the oil cooler is dumped into the channel right above #6 cylinder adding to the Heat in that area...And to add one more detail is the Piston Pin off-set of 1mm is not favorable to Bank 2, but is favorable to Bank 1 ( there is not OEM Bank Specific Pistons) ...This Piston PIn off-set adds more Heat and Friction to Bank 2 but lessens Heat and Friction to Bank 1..
Heat and Friction are not the same thing but are 1st cousins that effect each other...... As Friction rises it raises Heat , as Heat rises it raises Friction... This is a loop that must be under controll.... As either raises it lowers the oils ability to protect the surface and if it gets out of control Thermal Runaway can occur in localized or broad areas...
@Porschetech3
Skip my motor has 55k only driven on the track the past 18k, 110 days over the past 5 years. Never bore scoped or had an oil analysis. What would I gain by doing them now?
@hbdunn
Would you like to know if your engine has changed in the last 5 years/18K miles ?
But if the previous owned had accurately tested the Blow-by at WOT , the compression and leak down , Bore-Scoped it , tested oil pressure with 40wt at 90C and 4k RPM and documented all results and with pictures , then you did the same now, you would probably see a difference even if symptoms are not readily apparent ...
The Mezger GT3 Cup engines used in Competition are suggested to be rebuilt every 50 hours....can they be ran longer? Yes....
But you have put ~300 Track Hours on yours, do you think it is still the same as when you got it ??
I have been repairing and Troubleshooting engines for 50 years. Some people do fine not knowing a thing about how an engine works, just turn the key and drive and if it breaks, pull out the wallet and fix it...But one of the hardest things is telling that person that they were the cause of the failure by their not knowing how to take the best care of the engine...
If ll the owners knew what I know they would not ask any questions, just take responsibility for their own engines, and take their chances when they wanted to, ( to save some money ).. but not regret when the Porsche Gods punish them for being lazy or too frugal....
BTW :Here is a good SAE White Paper ( Society of Automotive Engineers ) on Al-Si Cylinders and bore scoring from Charles Navarro if you want to Geek-out on some techy stuff.
What world has it not changed? I assume it has so if it hasn't that's a win for me. I agree it would be great to know that info before purchasing a car but don't see any real advantage of me knowing it now. Tell me a scenario where I find out something from an oil analysis or bore scope and I'm able to do something that I'm not doing now to save my engine from the inevitable rebuild. For me the running clean heavier weight oil at the right level is the most important thing I can do. Your innovation contributes the most to this task. As you can imagine at this point it's more of an experiment now. See how long I can drive this car at least to my limits.
One day it won't make it on the trailer by itself and I'll be ok with that.
As always thanks for your knowledge and wisdom.
You are doing the right things Brad
And thanks for the kind words ..
I do enjoy seeing how many miles you can go on that engine as a testament to the 3.4 5 chain engines being ran hard..... It will be a good data point ..\\
I have been noticing ...Your driving is great also as I have seen in your video's..
LMAOO !!!.....Yeah I gotcha ...
I'm just giving credit where credit is due...
Brad doesn't worry about the engine, thats probably one reason he is such a good Driver...
Back in 1980, 81, 82 I was hired as a Driver for the Marschall Racing Team on a Fiberglass Pro Modified Fairmont with a 514 CI big block about 900hp... They would not let me work on the car .......... They said they hired me to drive and didn't want me to worry about what was happening in the engine.....I won a ton of races and several Track Championships in those 3 years with an 85% win/loose average.... They didn't even want me talking to people between rounds and would even run people off if they thought I was being distracted or loosing focus...lol......They did let me do some Tuning on it because that was really my forte
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