Originally Posted by
Krawl
But don't you think that carbon build up will eventually slippin' into the sleeve and make some scratches? Or it will messed the combustion chamber?
Carbon build up on the piston ring, is good thing, it is acting like a piston seal. It wont scracth the sleeve liner.
Carbon build up on top of piston and underneath the button head, they are not good. In severe conditions, the build up could cause pre-detonations, thus increasing the engine temperature.