Piston Rings
NOTE:
Compression rings differ in scraping edge design. From a cross sectional view, ring No. 1 has a barrel shaped scraping edge and ring No. 2 has a tapered edge.
- Measure piston ring side and end clearance for all pistons and replace rings as necessary. When replacing rings without boring, check ring end gap at lower part of cylinder that is less worn. When replacing a ring, be sure to use one of the same size.
- Install rings on piston with end gaps staggered at 120° intervals. Ensure no ring gap is in line with thrust face of pin bore. Also ensure manufacturer's marks are facing upward when rings are installed.
NOTE:
Stagger ring gaps to minimize compression loss.
CAUTION:
Install oil ring first without using a ring expander. Expander gap should be installed more than 45° from side rail gaps, and rails should turn smoothly when installed.
PISTON RING SIZES
| Ring Size | Size Mark |
|---|---|
| Standard | No Mark |
| 0.25 mm Oversize | 25 |
| 0.50 mm Oversize | 50 |
| 0.75 mm Oversize | 75 |
| 1.00 mm Oversize | 100 |