id like to hear some opinions&experiances with thermal coatings on the piston crowns.has anyone got pros or cons with this in a heavy hitting marine engine?

If you coat the head of the piston, you probably will need to do the chambers and valves as well.
You can just do the skirts though.

If its an all out race motor with fuel regulations and that sort of thing I think coatings have a place. Other than that I think it's a waist of money. Every used piston I've seen that was coated had the coating worn off in some way shape or form. At that point what good is it?

FWIW, some added info. I have been told that coating the exhaust valves alone is worth 5 hp but like above said the coatings will wear off at some point in time. David Vizard has a lot experience with coatings and he has recommended Calico for the past x amount years.

I coated the combustion chambers, valves and pistons (Thermal on dome, lubricating on skirts) on a 2.4L Turbo 4 when I built it. I have not had the motor back apart but it does make 450HP. For the extra cost, I would do it again, I also had the head, block, oil pan, trans case, etc... powder coated, and the turbo, manifolds, and plumbing ceramic coated, the motor still looks like new 30K miles later.





After 30K miles:

Why would you go to all the trouble for a lawn mower engine?

That lawn mower runs 10.70s on slicks, gets 31 MPG on the highway and has needed nothing but Oil changes since I put it together just over 31K miles ago

What was the MPH?

I just bought a book written by David Vizard. man knew his ****t thats for sure.

In my Blown Alky motors (Hemi) 3400 hp at 10,400rpm....DOUBLED the life of my pistons by Coating!