Originally Posted by
Roelof
No, it is a mater of more friction and less lubrication. Because the piston expands more at the exhaust side because it is much hotter over there the piston will create an egg shape pushing against the sleeve. Because there is no transfer port there is also less lubrication. With both things hapening it can create scratches and the amount and how deep is depending how carefull you are heating up the engine.
This is brand new engine with dirty manifold and pipe.
It happened twice with the same manifold and pipe ( 3 years I never clean the inside, ie. dirty )
The engine quit working after just few laps. I check the engine exhaust port and notice big scratches on the exhaust port.
I suspect the turbo charge effect ( or sonic pulse created from the pipe's cone ) is pulsing back some carbon dirts from manifold into combustion chamber.
