Piston Ring: Description and Operation

GENERAL
The piston rings have a slightly larger diameter than the piston. The top compression ring is made of stainless steel and the lower compression ring is cast iron. Both compression rings are flexible, allowing them to press against the cylinder wall and prevent fuel mixture leakage from the cylinder. The oil ring assembly consists of an oil ring and two rails. The oil ring scrapes oil from the cylinder wall to prevent it from entering the combustion chamber.