Are there any advantages to coated pistons other than helping with heat? What kind of milage does the coating last?

 

Properly done, the coating should last the life of the piston. I have heard of some reports of the coating improperly done and flaking has occurred. As far as the ceramic coating on the crowns are concerned, I do not believe there is a benefit other then protecting the crown from excessive heat. The piston skirts can be teflon coated. This is meant to reduce friction and therefore wear. I do not know of any emperical data that proves or disproves this to be the case.

 

So pretty much the top coating doesn't do anything unless your running higher egts?

 

As far as I am aware, yes. However, do not discount that benefit lightly! One experience with a melted piston will greatly incease in your mind the benefit. With the mods we run now days and the HP levels going up exponentially it seems, I would say if you are doing a rebuild, it is starting to make more sense to ceramic coat the crowns a very sound proposition.

 

Thats what im debating, i melted # 6 and taking my time on the short block looking at options with every part. The coating is kind of cheap insurance tho. But it is hard to get answers from any of the companies on exactly how much more heat it'll let the pistons take. The coating would keep the temp cycle swings from being so large to, so i guess that would add to the lifespan of the piston. My temps don't get very high as it is but with bigger stix down the road it's going to put them up more. More concerned about the reliablity of the coatings i guess.
Anyone have many miles on coated pistons?

 

I would say do your research and choose wisely. Like I said, I have heard of some coatings flaking. The company that did mine says there is a 200* benefit. Their coating is done with a molecular bonding process instead of being "painted on" so to speak.

I went through Haisley's to have mine done, I forgot who they used off the top of my head. They flycut the pistons then sent out for the coating... it took a couple of weeks to get them back. Like you said though, cheap insurance.

 

The ceramic coating on the top will make the heat spread out so you are not as likely to have hot spots, in addition to slowing down heat transfer. Most coatings on the skirts are a moly based as PTFE can't take nearly as much pressure as ceramic based coatings.

 

everything i've looked at has led me 2 hpc coatings anyone have any experience with them?

 

I used Swain Tech in New York once. I got a little grease on the coated piston top they did for me and wiped it off with some brake cleaner. LOL, the coating came right off with little to no elbow grease. I was disappointed enough that I no longer use them. Although, they now have a new process called "gold coat" that many guys in the gasser world have had good luck with.

just my two cents.


We have in-house coating here, but not for heat control, only friction. It is not tested long term on pistons yet. I hope to have some data in the next 6 months or so. So far it is working well on firearms and some Cummins internal engine parts. That wont help you on your goal of heat control though.

I like water injection for that.

 

Some ppl i've talked to said that water/meth causes a lot of the coatings to chip. The chipping seems like something i'd loose sleep over. I was throwing around the option but i dont want the coating taking out my motor.

 

From what I can see the best gains are in the piston skirt (to help with galling, perhaps hold a bit more oil, and might help with sticking issues). Most of the piston (crown) coatings I have seen break down (according to specification) at temperatures less than race diesel egts.

This stuff is all good, but I would suggest that you need to find out why the piston melted before you get too carried away with specialty coatings. A piston coating will not solve the problem.
The reason I mention this is that the R-700 twins will easily cool the amount of fuel that you are running....So that means something else is wrong.
What CP3 mod are you running and what does your rail pressure look like?

I have a motor in the shop and am considering the coating thing as well.....For me the jury is still out.

 

Pretty well narrowed the reason it melted to the injector hanging, having them flow checked next week. If it is, they'll be headed Dons way. N if not the case it'll be tracked down before the motor goes back in.

Just trying to make sure i get everything i want in the short block before it goes back together b/c i don't want to do it again.

 

If moderators would allow I could link a video of a half coated piston top and a torch, which blows a hole in the uncoated half.

 

I forgot to add, water meth should not effect, and if done properly, it takes several minutes of blasting to remove from each piston.

 

I'd love to see that?