Quote:
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.
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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