[68WarDog]

Recently I had my GTO NM engine refreshed since it hadn't been run in about 13 years. The cam was updated to a 224/231 @0.050, .480 lift on a 112 LSA hft.After using the Wallace compression calculator, we decided to leave the pistons .020 below deck. The Felpro 1016 gasket has a 4.3 gasket diameter , with. 039 crushed, and my #13s measured 78cc, putting the compression at 9.46. Talking with my engine builder we decided to ceramic coat the pistons top, to help prevent damaging the pistons should I get a tank of not so good 91/93 gas. Do ceramic coating really help against detonation damage? And how many builders are actually using ceramic coating?

[1968GTO421]

If you don't get a response by tonight, I'd post this in the Race secton as they are more apt to be using coatings on pistons and other internal parts.

[Steve C.]

Back in the day when I was "throwing" lots of money at my different engine combinations we used to coat the piston skirts and the dome. Did I notice a difference, No. But all the tech material indicates a positive approach.

https://www.polydyn.com/pistons

Thermal Barriers
In theory, heat management offers great potential for improving an engine's power output. Often, ceramic-based thermal-barrier coatings (TBCs) are used to reduce heat migration, reflecting heat rather than absorbing it. They may be applied to piston-top surfaces and top ring grooves, combustion chambers, exhaust-valve heads and faces, exhaust manifolds and headers, and inside exhaust ports.

https://www.motortrend.com/how-to/hr...gine-coatings/



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[AIR RAM]

On my current build, I had the piston tops, the combustion chambers and the exhaust ports all ceramic coated.

I'm just following the science/theory of operation. I plan to use every trick in the book to minimize exhaust heat transferred to the heads.

I think there is merit to ceramic coatings so I opted for them.

SPEED SAFE, NICK

[Don 79 TA]

not sure if this is helpful or not, but on my jetski engines i used coatings on the pistons
i do crank the heck out of the compression too
these are two strokes, so what i have heard is its a big benefit for them
i was able to run some hi comp on 110 fuel with no issues when i was told it should be 112+, and that was out in the high dessert heat temps too
however piston technology has also come a long way, and cryo treating wasn't readily available, well not in my build time frame windows
i also just see it as "extra" insurance so to speak
i did debate this with a high end engine builder, and he gave me another angle that he looks at, i dont recall what it was, but something about wanting to retain some of the heat. he's a wealth of engine knowledge so i am sure he had tested reasons, and it might have been for specific builds too
i thought i read, and was probably told from either the coaters/builders/manufacturers that you have take ring gaps into consideration, now again this might have just been 2 stroke related. it was something about heat.

to me, if you are playing in the ragged edge of tuning it probably wouldn't hurt.

[Randy Allen]

I’d do exactly what Nick did and then talk to the builder about Hard anodizing the rings for extra top ring protection. It’s generally done in boosted applications but extra insurance for detonation. I’ve used Swain Tech for exhaust(headers, manifolds, down pipes, Y pipes) and their White Lightning coating. They have specific products for the coating job . Builders are mixed on coatings for engines; often because of turnaround time. In your case, if the builder is for coatings it sounds like he wants to add the extra protection. Will it provide a speed advantage; probably not to our level of testing but you’ll ensure you have better detonation protection.

[Formulabruce]

Originally Posted by 68WarDog

Recently I had my GTO NM engine refreshed since it hadn't been run in about 13 years. The cam was updated to a 224/231 @0.050, .480 lift on a 112 LSA hft.After using the Wallace compression calculator, we decided to leave the pistons .020 below deck. The Felpro 1016 gasket has a 4.3 gasket diameter , with. 039 crushed, and my #13s measured 78cc, putting the compression at 9.46. Talking with my engine builder we decided to ceramic coat the pistons top, to help prevent damaging the pistons should I get a tank of not so good 91/93 gas. Do ceramic coating really help against detonation damage? And how many builders are actually using ceramic coating?

I know people " cringe" after their fun at the desktop
Tools, but here goes. Your calculated STATIC CR of 9.46 will most likely be at around 8.5 DYNAMIC. ( running).
This should be perfect for even 89 octane depending on your timing and fuel adjustment. Sounds like a good build even without the ceramic.

[AIR RAM]

Originally Posted by Don 79 TA

not sure if this is helpful or not, but on my jetski engines i used coatings on the pistons
i do crank the heck out of the compression too
these are two strokes, so what i have heard is its a big benefit for them
i was able to run some hi comp on 110 fuel with no issues when i was told it should be 112+, and that was out in the high dessert heat temps too
however piston technology has also come a long way, and cryo treating wasn't readily available, well not in my build time frame windows
i also just see it as "extra" insurance so to speak
i did debate this with a high end engine builder, and he gave me another angle that he looks at, i dont recall what it was, but something about wanting to retain some of the heat. he's a wealth of engine knowledge so i am sure he had tested reasons, and it might have been for specific builds too
i thought i read, and was probably told from either the coaters/builders/manufacturers that you have take ring gaps into consideration, now again this might have just been 2 stroke related. it was something about heat.

to me, if you are playing in the ragged edge of tuning it probably wouldn't hurt.

Do you race your Jetski's? 112octan requirement is insane! That must be a freaking blast!

Based on the research I have done (take with grain of salt) combined with my limited knowledge of the "theory of operation", over the years I have learned a few things about ceramic coatings.

Its really difficult to find first hand experience and most of the information is posted by the manufactures and or shops performing the coatings... So that leaves me skeptical right from the get go. I'm just shocked there are no real testimonies about ceramic coatings... Does this mean nobody is using them? Does this mean they dont work?.. coatings have been around for 20-25 years and readily available for us common folk for 10-15 years... and finding a positive first hand review is very difficult.... but you cant find negative first hand reviews either...

We all know, if ceramic coatings where bad or not worth it, the entire world would know the very next day! "They say lose lips sink races" or something like that...lol. I'm betting more people use them than saying and just not sharing the details because coatings may be part of their racing program and potential edge.

The theory is sound, the coatings actually help prevent absorption and retain the heat (energy) inside the combustion chambers as well as throughout the exhaust system assuming the headers are coated as well. The longer you can keep the heat created within the system (not absorbed) the longer it can work to your advantage. The goal should be to keep the exhaust heat "contained" in the system right up to the exhaust tip. Once its gone, it can no longer work for you. We dont want our system to absorb it while its there working. This is why Turbo Wraps have gotten so popular, they do help keep us from getting burned, but they also keep that Turbo Heat (energy) contained within the turbo. A hot turbo is said to spool quicker.

Preventing the heat from being lost through absorption is the goal because if allowed to absorb into certain areas, it can eventuality accumulate and work against the engine. The two places you really dont want the heat to be absorbed is the pistons and combustion chambers as hotter surfaces within the combustion chamber can lead to pre-ignition. This would be a case of absorbed energy working against our goals.

I honestly feel the biggest down side to adding coatings is that you will be stuck with those "1 off" custom coated parts if replacements are needed. If you hurt one piston, well now you cant use an off the shelf piston (quick) and will have to send the piston off to be coated +1-2 weeks (and that's in a non O'biden economy). If you hurt a head that's been coated, that's even more time to repair then send off for ceramic coatings.

A person with non coated parts can just get the non coated replacement and slap it on and get back to racing.

But, the coatings in theory SHOULD not only protect the parts and give them a longer service life, they SHOULD make tuning and consistency easier... in theory at least. I also believe they add a layer of protection to the parts allowing your engine to be more resistant to damaged caused by excessive heat.

Hopefully this tread will gain the attention of someone with actual first hand experience and DYNO time to back them up... I would assume with all the years of R&D TomV has seen, he would have some form of experience to add and would be great to hear his views... But I dont know if he has done any testing with ceramic coatings or not.


SPEED SAFE, NICK

["QUICK-SILVER"]

With bad detonation, coating piston tops will not stop busted rings and crushed ring lands.

Clay

[Jay S]

I have done a few different ceramic coatings on engine parts, there are a lot of different reasons you might want to run a ceramic coating. But I am not sure reducing detonation should be one of them. I can think of examples where piston coatings made a little less than a 10 hp increase in power on a 500+ hp engine. But I have seen arguments both ways for how it effects the engine. One school of thought says the piston runs cooler and is reflecting the temps back into the chamber. The other school of thought suggest by reflecting the heat the piston can not transfer as much heat, and it is raising the combustion temp, and can make preignition occur earlier. My guess is both those ideas are correct. Lol

I don’t know what they have in mind for a coating. I understand some thermal coatings disperse heat instead of reflecting it so the piston survives to make more power, others reflect to make more power. On a stockish engine, with a stock type piston I doubt the coatings would gain much of anything on detonation. For detonation my best guess is the dispersion would do more than reflection, I am guessing the ceramic type that they are looking at is the reflection.

I don’t think Ceramic coating the exhaust results in better thermal efficiency. More it effects the thermal efficiency from a change in the speed of the exhaust by effecting the temperatures. It is like putting a little longer tube header on your car. IRC, it is because the temp change effects the sonic number, the pulse the header excepts becomes longer.

We have worked on some cast piston engines that have had detonation to the point that we burnt the moly coating off the top compression ring. You could nearly pull the top ring off like a piece of baling wire, tension was gone. I know ring lands and rings can break too. But a lot of times I think it is from not quite enough ring end gap. The detonation produces excess heat, then bad stuff happens. Once the land or ring breaks and you still have detonation, everything gets worse fast. The combustion becomes a blow torch. IRC we have ran 23 lbs of boost with a cast piston, survive at least for the testing. If you have concerns about detonation I would gap the rings wider, use a cast type top ring, or ring design to take more heat than moly, and 45* valve instead of 30*s. Then add your piston coatings.

[Don 79 TA]

Originally Posted by AIR RAM

Do you race your Jetski's? 112octan requirement is insane! That must be a freaking blast!
SPEED SAFE, NICK

No we didn't race. rec riders, but i am hardcore when i do things sometimes. I personally have a passion for high compression... just something about the snap and wind up (jetski or car, and the high compression sound). just my personal preference.
I also obtained fuels at GREAT prices too, so non-issue (at the time).
I also had very high compression because i wanted instant bottom end snap in my skis (2 strokes i seriously felt difference as i had interchangeable domes), riding gear on and all i'd be hitting the scales well over 300#s ++ when wet (wetsuite retains water and i'm 240+) skis are probably close to 350#s maybe more (reinforced and all). that is what i liked for my riding style, and so did my wife.
was a blast every time pro riders would ride my skis, they were shocked as heck at the snappy power. not to mention most were at least 60#'s or more lighter. wife would get on my ski whack the throttle right off a start and pop the whole ski out of the water... funny to watch... especially when she rode in the buff so to speak lol....... Ahhh the days of being young....

as i said i can't say for sure that the coatings helped, but i did it as a precaution
many piston companies now offer that. after i started the crazy of coating, quiet a few others followed, and some of the ones dealing with high temps when racing said they noticed a difference, seems warm water folks seriously noticed.
i also did full exhaust coatings too, etc... and it really wasn't much either.

one builder said after looking at how many hours i went on it (i want to say at least 15+ drums of fuel), he couldn't believe when he did the tear down how mint the engine was inside for the compression i ran. 2 strokes have a short life when run on the ragged edge. this was a stoker motor with a very high pitched prop for a 1-2 hit so to speak. i also NEVER windmill my engines either, especially since i knew the props i ran. (props short for impellors)