Piston Ring: Service and Repair
PISTON RING1) Make sure the piston ring is not broken or damaged.
2) Using a cylindrical guide, insert the piston ring into the cylinder liner so that they are perpendicular to the cylinder wall, and check the piston ring gap using a thickness gauge. If it is not within the standard, replace the piston ring.
NOTE:
- Measurement should be performed at a temperature of 20°C (68°F).
- Use piston ring with same size as piston when replacing piston ring.
Piston ring gap:
Compression ring (top ring)
Standard
0.20 - 0.35 mm (0.0079 - 0.0138 in)
Compression ring (second ring)
Standard
0.40 - 0.50 mm (0.0157 - 0.0197 in)
Oil ring (upper rail and lower rail)
Standard
0.20 - 0.50 mm (0.0079 - 0.0197 in)
3) Fit the compression ring straight into the piston ring groove, then check the clearance between compression ring and piston with a thickness gauge. If it is not within the standard, replace the compression ring.
NOTE:
- Measurement should be performed at a temperature of 20°C (68°F).
- Before inspecting the clearance, clean the piston ring groove and compression ring.
- Use compression ring with same size as piston when replacing compression ring.
Clearance between compression ring and piston:
Top ring
Standard
0.040 - 0.080 mm (0.0016 - 0.0031 in)
Second ring
Standard
0.030 - 0.070 mm (0.0012 - 0.0028 in)
