Piston Ring: Testing and Inspection

RING GAP
1. Wipe the cylinder bore clean. Insert ring and push down with piston to ensure it is square in bore. The ring gap measurement must be made with the ring positioning at least 12 mm (0.47 inch) from bottom of cylinder bore.
2. Check gap with feeler gauge.
Standard value:
Upper ring 0.23 - 0.52 mm (0.009 - 0.020 inch)
Intermediate ring 0.49 - 0.78 mm (0.019 - 0.031 inch)
Oil control ring 0.23 - 0.66 mm (0.009 - 0.026 inch)
Limit:
Upper ring 0.8 mm (0.031 inch)
Intermediate ring 1.0 mm (0.039 inch)
Oil control ring 1.0 mm (.039 inch)





3. Check piston ring to groove side clearance.
Standard value: 0.025 - 0.065 mm (0.0010 - 0.0026 inch)
Limit: 0.10 mm (0.004 inch)