Originally Posted by
Briguy
Pitting is little pin holes starting to develop in the piston . This can happen from too much compression , not enough shims or longer glow plug .
Pitting is surface deformation on the piston head and underneath the button head. They become sand blasted due to overheating, perhaps due too high percentage on nitro % or running too lean.
I've got this pitting problem 3 times......
To reduce pitting : polish the piston head and button head until they become so shiny. I find this trick work very well to minimize pitting. I use dremel and round wool type tip, especially meant for polishing jewerly.
Don't polish inside the sleeve or inside the engine wall where the sleeve is seated.