Piston Ring: Testing and Inspection

SIDE CLEARANCE
Measure the side clearance as shown.
- Top ring 0.040 - 0.080 mm (0.0016 - 0.0031 inch)
- Maximum limit of side clearance is 0.1 mm (0.004 inch)
- If out of specification, replace piston ring. If the clearance exceeds maximum limit with new ring, replace piston.






END GAP
Measure the end gap as shown.
- Top ring 0.20 - 0.44 mm (0.0079 - 0.0173 inch)
- Oil ring 0.20 - 0.69 mm (0.0079 - 0.0272 inch)
- Maximum limit of ring gap is 0.49 mm (0.0193 inch) for the top ring and 0.69 mm (0.0272 inch) for the oil ring.
- If out of specification, replace piston ring. If gap exceeds maximum limit with new ring, rebore cylinder and use oversized piston and piston rings.
- When replacing the piston, check the cylinder block surface for scratches or seizure.
- If scratches or seizure is found, hone or replace the cylinder block.