Originally Posted by rcabj

guys..after a full day race, i disassemble my engine. everything looks fine except the top surface of piston head which had quite a few small spots ( feels sandy ). it also appears on the bottom part of turbo button ( the area around the glow plug.) , has anyone experience this too? so what could be the cause of these and what should i do to prevent this from happening again.

and how do i remove this sandy spots stains, ? thanks