Piston Rings: Installation
The No. 1 and No. 2 piston rings have a different cross section. Install rings with manufacturers I.D. mark facing up, to top of piston. Install piston rings in the following order: See Fig 1.
- Oil ring expander.
- Lower oil ring side rail.
- Upper oil ring side rail.
- No. 2 intermediate piston ring.
- No. 1 upper piston ring.
- Install oil ring expander. Install lower oil ring side rail by placing one end between piston ring groove and expander. Hold end firmly and press down portion to be installed until side rail is in position. Do not use a piston ring expander. Install upper oil ring side rail.
- Install No. 2 piston ring and then No. 1 piston ring. Position piston ring end gaps as shown in Fig 2. Position oil ring expander gap at least 45° from side rail gaps, but not on piston pin center or on thrust direction. Staggering ring gap is important for oil control.