Abstract: A sealing system for the compression ring (5) of a piston (1) of an internal combustion engine comprises placing an elastomeric material seal ring (15) behind the compression ring (5) to provide sealing to improve compression ratio and prevent loss of oil. The seal ring may be an O-ring of a neoprene/silicon blend elastomeric material of circular, U-shaped, oval, square, rectangular or trapezoidal shape, and may be hollow or solid. The seal ring may have a cross-sectional diameter of from 50% to 100% of the thickness of the compression ring (5) behind which it fits.