CRANKSHAFT, CAMSHAFT, CONNECTING ROD, PISTON AND VALVE MECHANISM Serial No. 5T1 to 5T6941 inclusive. 4F9868 Piston Ring Group consists of complete set of rings for two 2F3665 Pistons. 4F9869 Piston Ring Group (.010 O'size), 4F9870 Piston Ring Group (.020 O'size), 4F9871 Piston Ring Group (.030 O'size), or 4F9872 Piston Ring Group (.040 O'size), each consists of a complete set of rings for two 2F3664 Pistons.