Piston Rings Piston Rings are made from high quality Grey C.I. Castings (Individual Casting) that has very fine grain to offer high tension at elevated temperatures of high-speed engines. The piston rings manufacturing range vary from 23b mm to 120 mm dia and are made for varied applications in cars, trucks, LCV's, tractors, industrial and diesel engines, air and gas compressors, ammonia compressors.