The State of Piston Re-Coating. Anybody successfully doing it?
09-23-2016, 12:28 PM
#16
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Yea this topic is a can of worms alright. Reading about how many coatings have failed even after the rigorous testing by manufacturers, tells you what the odds are of us figuring it out.
The 997 engine is now in the hot seat with the latest block coating starting to fail for people. It's similar to Nikasil, but not exactly the same and issues with Nikasil in production engines are well known.
Funny thing is, our block material with the original Mahle coating (shared by Mercedes V8's of the same generation, and some BMW's along the way) is looking to be the best option but they keep trying to reinvent the wheel probably because of the cost associated with making the Silica blocks, the special cylinder treatment needed and iron piston coating. If it was cheaper to do, they would still be using it.
What's next? Ford co-developed a plasma arc coating being used in the new GT350 engine. Time will tell if this lasts:
http://www.hotrod.com/articles/ford-...flat-plane-v8/
The 997 engine is now in the hot seat with the latest block coating starting to fail for people. It's similar to Nikasil, but not exactly the same and issues with Nikasil in production engines are well known.
Funny thing is, our block material with the original Mahle coating (shared by Mercedes V8's of the same generation, and some BMW's along the way) is looking to be the best option but they keep trying to reinvent the wheel probably because of the cost associated with making the Silica blocks, the special cylinder treatment needed and iron piston coating. If it was cheaper to do, they would still be using it.
What's next? Ford co-developed a plasma arc coating being used in the new GT350 engine. Time will tell if this lasts:
http://www.hotrod.com/articles/ford-...flat-plane-v8/
09-23-2016, 01:52 PM
#17
Rennlist Member
We have over 100,000miles on the Devek stroker 6liter for gregory in norcal that had some formula for the coatings.... stilll running strong and has been abused a lot over the years!
whatever Marc did , he did right in this engine.
Mark
whatever Marc did , he did right in this engine.
Mark
Yea this topic is a can of worms alright. Reading about how many coatings have failed even after the rigorous testing by manufacturers, tells you what the odds are of us figuring it out.
The 997 engine is now in the hot seat with the latest block coating starting to fail for people. It's similar to Nikasil, but not exactly the same and issues with Nikasil in production engines are well known.
Funny thing is, our block material with the original Mahle coating (shared by Mercedes V8's of the same generation, and some BMW's along the way) is looking to be the best option but they keep trying to reinvent the wheel probably because of the cost associated with making the Silica blocks, the special cylinder treatment needed and iron piston coating. If it was cheaper to do, they would still be using it.
What's next? Ford co-developed a plasma arc coating being used in the new GT350 engine. Time will tell if this lasts:
http://www.hotrod.com/articles/ford-...flat-plane-v8/
The 997 engine is now in the hot seat with the latest block coating starting to fail for people. It's similar to Nikasil, but not exactly the same and issues with Nikasil in production engines are well known.
Funny thing is, our block material with the original Mahle coating (shared by Mercedes V8's of the same generation, and some BMW's along the way) is looking to be the best option but they keep trying to reinvent the wheel probably because of the cost associated with making the Silica blocks, the special cylinder treatment needed and iron piston coating. If it was cheaper to do, they would still be using it.
What's next? Ford co-developed a plasma arc coating being used in the new GT350 engine. Time will tell if this lasts:
http://www.hotrod.com/articles/ford-...flat-plane-v8/
09-23-2016, 02:42 PM
#18
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Probably has 968 pistons.
__________________
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
09-23-2016, 02:48 PM
#19
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One of these days I'm planning on putting my engine back together. I keep going back and forth on just going ahead with everything as it sits now, or to really dig in and get it factory fresh.
Some of the pistons are a little shinier towards the bottom of the skirts than I'd like. Has anyone reliably been able to re-coat them? Most of the posts on this are pretty old, and there really isn't much follow-up with the folks who've done it.
I'm at work without pics now, but I can post some when I get home.
Some of the pistons are a little shinier towards the bottom of the skirts than I'd like. Has anyone reliably been able to re-coat them? Most of the posts on this are pretty old, and there really isn't much follow-up with the folks who've done it.
I'm at work without pics now, but I can post some when I get home.
Some pictures would be nice. I've seen a very few sets of 928 pistons that I would not re-use.....and all of them had 250,000+ miles on them.
09-23-2016, 02:53 PM
#20
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What is the inevitable? What makes you think this is ever going to be a problem? Greg builds stroker race engines with used - non recoated - 968 pistons.
It's not an issue, move on, don't worry about it. The only time this is an issue is building custom engines where non-stock pistons comes into play.
Some claim the coating is only needed when breaking in a fresh bore, which is questionable since Greg doesn't re-coat the 968 pistons he puts in bored out blocks for strokers.
There is a 928 engine running around Green Bay with Swain Tech's skirt coating applied. These were used pistons in old bores, the coating was applied as a friction reducer for power, not "refreshing" the original coating.
It's available, just not to us mere mortals. Mahle of Europe can still make pistons for our engines, but not in a quantity that makes it feasible.
Many years ago, Mahle USA claimed to have the same process and many projects were started. It was soon discovered said coating was crap and engines were lost. Very long story short, years later a rep from Mahle claimed they "fixed" the problem and wanted us to try again. Not willing to chance another motor, we didn't take them up on their offer.
Could the issues with motors being discussed here be due to incorrect tolerances and / or rig gap? Maybe, but that means nobody knows the formula for our blocks with these new pistons and it's a very expensive trial and error to figure it out.
So...if you send Greg a briefcase full of money and have Mark Anderson truck over a dozen blocks, I'm sure he could figure out the magic formula.
It's not an issue, move on, don't worry about it. The only time this is an issue is building custom engines where non-stock pistons comes into play.
Some claim the coating is only needed when breaking in a fresh bore, which is questionable since Greg doesn't re-coat the 968 pistons he puts in bored out blocks for strokers.
There is a 928 engine running around Green Bay with Swain Tech's skirt coating applied. These were used pistons in old bores, the coating was applied as a friction reducer for power, not "refreshing" the original coating.
It's available, just not to us mere mortals. Mahle of Europe can still make pistons for our engines, but not in a quantity that makes it feasible.
Many years ago, Mahle USA claimed to have the same process and many projects were started. It was soon discovered said coating was crap and engines were lost. Very long story short, years later a rep from Mahle claimed they "fixed" the problem and wanted us to try again. Not willing to chance another motor, we didn't take them up on their offer.
Could the issues with motors being discussed here be due to incorrect tolerances and / or rig gap? Maybe, but that means nobody knows the formula for our blocks with these new pistons and it's a very expensive trial and error to figure it out.
So...if you send Greg a briefcase full of money and have Mark Anderson truck over a dozen blocks, I'm sure he could figure out the magic formula.
I did assemble Anderson's race engine with used 968 pistons that had been run in the same bores, in his own engine, from new.
It's not that I have anything against used pistons, but two good sets of used 968 pistons are tough to come by....and the sizes of the 968 pistons is a bit crazy....they are "all over the map".
09-23-2016, 03:03 PM
#21
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Yea this topic is a can of worms alright. Reading about how many coatings have failed even after the rigorous testing by manufacturers, tells you what the odds are of us figuring it out.
The 997 engine is now in the hot seat with the latest block coating starting to fail for people. It's similar to Nikasil, but not exactly the same and issues with Nikasil in production engines are well known.
Funny thing is, our block material with the original Mahle coating (shared by Mercedes V8's of the same generation, and some BMW's along the way) is looking to be the best option but they keep trying to reinvent the wheel probably because of the cost associated with making the Silica blocks, the special cylinder treatment needed and iron piston coating. If it was cheaper to do, they would still be using it.
What's next? Ford co-developed a plasma arc coating being used in the new GT350 engine. Time will tell if this lasts:
http://www.hotrod.com/articles/ford-...flat-plane-v8/
The 997 engine is now in the hot seat with the latest block coating starting to fail for people. It's similar to Nikasil, but not exactly the same and issues with Nikasil in production engines are well known.
Funny thing is, our block material with the original Mahle coating (shared by Mercedes V8's of the same generation, and some BMW's along the way) is looking to be the best option but they keep trying to reinvent the wheel probably because of the cost associated with making the Silica blocks, the special cylinder treatment needed and iron piston coating. If it was cheaper to do, they would still be using it.
What's next? Ford co-developed a plasma arc coating being used in the new GT350 engine. Time will tell if this lasts:
http://www.hotrod.com/articles/ford-...flat-plane-v8/
I've been told that the pistons are not iron plated, but have a high tech coating.....which fails.
Imagine that!
I've been told that Porsche refuses to acknowledge the issue (apparently the problem is concentrated in vehicles that have been in very cold weather), but avoiding a class action law suit over the matter seems highly unlikely.
I find it almost humorous that a company that had perfected Alusil would go away from a proven process to save a few dollars per cylinder and piston.
I'm betting that the older engineers are laughing their a$$es off at the bean counters.....
09-23-2016, 03:14 PM
#22
Administrator - "Tyson"
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For anyone bored, here is one thread on the 997 issue:
https://rennlist.com/forums/rennlist...confirmed.html
https://rennlist.com/forums/rennlist...confirmed.html
09-23-2016, 04:12 PM
#23
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Yea this topic is a can of worms alright.
What's next? Ford co-developed a plasma arc coating being used in the new GT350 engine. Time will tell if this lasts:
http://www.hotrod.com/articles/ford-...flat-plane-v8/
What's next? Ford co-developed a plasma arc coating being used in the new GT350 engine. Time will tell if this lasts:
http://www.hotrod.com/articles/ford-...flat-plane-v8/
bone stock with a warranty !
09-23-2016, 05:17 PM
#24
Rennlist Member
actually, if you remembrer, it was a 6liter so used a custom JE or Weisco piston with his proprietary coating. the first motor overheated and had issues. i think the repair was a short block only and some shaved heads because they said they were warped from the overheat. i forgot the details, other than it is a 100mm piston with the devek stroker crank and corrillo rods
09-23-2016, 05:57 PM
#25
Rennlist Member
I was considering a Cayenne for a while and the early cars have the same issue. My understanding is that the tolerances are too tight and after a cold weather start the piston heats and expands more quickly than the block so you end up with too tight of a fit, damaged coatings, and scored blocks. My impression is that Jake Raby understands the situation and can fix it for big $, but that the factory just denies it.
09-24-2016, 08:47 PM
#27
Nordschleife Master
What's next? Ford co-developed a plasma arc coating being used in the new GT350 engine. Time will tell if this lasts:
http://www.hotrod.com/articles/ford-...flat-plane-v8/
http://www.hotrod.com/articles/ford-...flat-plane-v8/
old (before they became garbage) Jalopnik article on it:
http://jalopnik.com/5467038/the-ford...he-nissan-gt-r
Apparently it can be used to recondition old cylinder bores on Aluminium engines:
http://flame-spray.com/index.php?opt...d=73&Itemid=53
http://newatlas.com/ford-plasma-engine/40728/
09-24-2016, 10:45 PM
#28
Three Wheelin'
For anyone bored, here is one thread on the 997 issue:
https://rennlist.com/forums/rennlist...confirmed.html
https://rennlist.com/forums/rennlist...confirmed.html
09-25-2016, 07:27 PM
#29
Yea this topic is a can of worms alright. Reading about how many coatings have failed even after the rigorous testing by manufacturers, tells you what the odds are of us figuring it out.
The 997 engine is now in the hot seat with the latest block coating starting to fail for people. It's similar to Nikasil, but not exactly the same and issues with Nikasil in production engines are well known.
What's next? Ford co-developed a plasma arc coating being used in the new GT350 engine. Time will tell if this lasts:
http://www.hotrod.com/articles/ford-...flat-plane-v8/
The 997 engine is now in the hot seat with the latest block coating starting to fail for people. It's similar to Nikasil, but not exactly the same and issues with Nikasil in production engines are well known.
What's next? Ford co-developed a plasma arc coating being used in the new GT350 engine. Time will tell if this lasts:
http://www.hotrod.com/articles/ford-...flat-plane-v8/
Piston coating is certainly a can of worms, I did think about getting the pistons hard chrome plated but they already had a piston coating on them so decided to go another way.
The GT3 engine and turbo engine in the 997 are nicasil as they are different engines to the other family of Porsche engines. As long as the fuel is good there is no problem. This coating was used in the last generation of F1 engines, I cannot comment on current generation engines as they are very secretive. The other coating is Sumebore,
This is used in F1 and NASCAR and Porsche engines such as the Cayenne. It is even in the Buggatti Chiron engine.
I don't think ford developed the wire transfer system first. Sumebore has been around a while. I had an enquiry about using this in the 928. I was privileged to quite a lot of information and there is many different formulas for sumebore. First the cylinder is grooved,
My cutter but requiring the special tip.
This is the factory cutter
So the coating is a purely mechanical key.
The cylinder was prepared is then sprayed with the plasma and then diamond honed lined the nicasil.
We may use this system on the replaceable liner engines. You just need a rotater, but for a block you need their machine set up on your block like the OEMs do. This would be expensive. The coating is the same thickness as the nicasil at 150 microns. The coating is diamond honed like the nicasil.
