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)
^ 2nd ring 0.030 - 0.070 mm (0.0012 - 0.0028 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 0.28 - 0.52 mm (0.0110 - 0.0205 inch)
^ 2nd ring 0.45 - 0.69 mm (0.0177 - 0.0272 inch)
^ Oil ring 0.20 - 0.69 mm (0.0079 - 0.0272 inch)
^ Maximum limit of ring gap is 1.0 mm (0.039 inch)
^ 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.