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THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHCommon problem across all Porsche engine?
Leading reported evidence
Use today must have a piston coating
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All cylinders materials used today must have a piston coating on them to survive (except iron based cylinders and Nikasil coated cylinders).
Leading evidence: 'Use today must have a piston coating' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Use alusil' (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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Suggestion
They could have used Alusil, it's not just environmental but a desire to be cheap.
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Suggestion
Also the 928 and 944 were using Alusil cast engines.
Use electroplating was the most robust and worked well
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Suggestion
What I'm saying is that I think the Ferrostan process using electroplating was the most robust and worked well for 30 years , the newer coatings such as Mahle Ferrorprint, Ferrotec, and Kolbensmits Ferrocoat, are resin based with iron based particles that work under ideal conditions, when things get too far from ideal they are not as durable.
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Suggestion
Jeep had to start coating all thier pistons back in teh mid 90's,, and they use iron blocks,
Use electroplating was the most robust and worked well
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Suggestion
What I'm saying is that I think the Ferrostan process using electroplating was the most robust and worked well for 30 years , the newer coatings such as Mahle Ferrorprint, Ferrotec, and Kolbensmits Ferrocoat, are resin based with iron based particles that work under ideal conditions, when things get too far from ideal they are not as durable.
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Suggestion
As someone who mostly messes with older cars, I have a dumb question - are you telling me the modern pistons for alusil engines no longer use an iron coating?
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Suggestion
I'm the original owner in FL and I guess maybe since my car gets used once a week I have never had any issues with it other than an alternator and a cab piston.
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Suggestion
The push toward lighter weight, low fuel consumption, and lower emissions, has caused the manufacturers to use specialized lightweight materials for cylinders w/piston coatings and tighter clearances, all which make bore scoring more susceptible..
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28 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
Yep, cylinder bore scoring! The bore scope images say a thousands words. Jake Raby and Charles Navarro says its affecting cars beyond the M96/M97 911 engine platform. Even the 9A1 guys!
The tech mentions the car was driving with a low oil indicator implying that low oil could be the cause, but really oil consumption is a symptom of the problem. Sadly, the customer refused service which probably meant a rebuild or replacement engine. Ouch!
Yep, common day in a dealership.
I don't think it is just Porsche having bore scoring issues. The push toward lighter weight, low fuel consumption, and lower emissions, has caused the manufacturers to use specialized lightweight materials for cylinders w/piston coatings and tighter clearances, all which make bore scoring more susceptible..
Emissions regs hurt, but so does the constant spread of misinformation by people who don't understand that times change and with them so to have cars. Wasn't it in a recent Panamera Magazine that someone claimed by virtue of flying planes he is an expert in engines and thus he knows you should idle a cold engine to let it warm up?
I wouldn't sell yourself or your car short. The C4S 996 cars have strong demand even with the OEM bearing. Of course, if the bearing is addressed, then you'll attract a wider buyer pool. But I wouldn't throw in the towel just because these cars suffer from scoring. That may not be the case in your car.
I'm not really understanding why Porsche has this issue. Too cheap to coat correctly?
By contrast my aluminum block Audi D2 S8 has 240k miles on the original engine - heads have never been off. Ditto for my wife's 2.0 turbo aluminum engine in her C7 A6. Why can Audi do this but Porsche cannot?
They (Porsche and others) moved away from proven Nikasil because of stricter environmental regulations. You should watch Jake Raby's video on Bore Scoring. Very thorough explanation of the problem.
https://www.youtube.com/playlist?lis...iZKhfNjeTXaRkn
A lot comes down to the owner. You are far more likely to find a Porsche driver saying "I garage it in the winter, other than starting it once a month and letting it run to circulate the fluids."
They could have used Alusil, it's not just environmental but a desire to be cheap.
Alusil came later. The 9a1 engine made the swap starting in 2009. The M48 Cayenne was Alusil from the beginning. Cayenne engines have more issues with bore scoring than the M9X, and we are seeing Alusil failures routinely with the 9a1 engine today.
Mercedes was using Alusil in the 80s, there was no reason Alusil had to come later for Porsche. I am very surprised you are seeing routine Alusil failures though. Kolbenschmidt has known how to make Alusil work for a long time now, I wonder what changed.
Its the other variables that come into play with routine operation of these engines that are being the major contributors to the failures. Lots of these failures begin with the failure of the piston, first.
Mine is an 03 C4S w/ original IMS and Tip. Bought at around 78k miles and right under 92,4xx now after 23 mo's of ownership. Never worried about IMS a day I've owned it. Just get out and drive and enjoy your fantastic car!
Thanks guys but I guess my sarcasm didn't read through! I'm the original owner in FL and I guess maybe since my car gets used once a week I have never had any issues with it other than an alternator and a cab piston.
Also I drive it pretty hard, consistently hit 5k on the tach and just had it up in the 125mph range a week or two ago.
Porsche started using Alusil (Kolbensmidt) in 1974 in the 911 air-cooled engines, and was using Nikasil (Mahle) at the same time. In fact you would have to look for the makers stamp to see which cylinder/piston you had.(or know from experience/looking)
Also the 928 and 944 were using Alusil cast engines. The problem with casting a complete engine from Alusil is that the hypereutectic material is costly/difficult to machine and wears out tooling. That's the reason for the introduction of Lokasil, you had a hard hypereutectic cylinder with an easy to machine hypoeutectic case.
I think the issues came when Porsche was forced to stop doing the Ferrostan process for piston coatings for MY2002. Ferrostan process(iron/tin clad coating) was determined to have small amounts of cyanide in the sludge of the electrolyte bath and deemed environmentally unsafe.
All cylinders materials used today must have a piston coating on them to survive (except iron based cylinders and Nikasil coated cylinders). So basically the survival of the cylinder depends on the piston coating, if the coating flakes or wears off, the cylinder will fail.
Nikasil or Iron based cylinders can survive without a piston coating, but sometimes coatings are used and if the coating wears off, the cylinder does not fail, but will have increased clearance.
Jeep had to start coating all thier pistons back in teh mid 90's,, and they use iron blocks,
the "blame" was placed on the oil, and the offset Wrist pin..
Low revving high torque engines don't seem to like the offset..
There were multiple piston related recalls form about 1992 through 2000..
Well that explains everything. As someone who mostly messes with older cars, I have a dumb question - are you telling me the modern pistons for alusil engines no longer use an iron coating?
What I'm saying is that I think the Ferrostan process using electroplating was the most robust and worked well for 30 years , the newer coatings such as Mahle Ferrorprint, Ferrotec, and Kolbensmits Ferrocoat, are resin based with iron based particles that work under ideal conditions, when things get too far from ideal they are not as durable.
There are literally dozens of other piston coatings that contain mixtures of other elements that work under ideal conditions, but seam to fail under less than ideal circumstances.
Iron based or Nickle Phosphorus Boron Nitride seam to be the most robust.
