Piston Ring, Engine

PISTON RING SIDE CLEARANCE





^ Measure the side clearance of piston ring and piston ring groove with a feeler gauge.
Standard:
Top ring : 0.045 - 0.080 mm (0.0018 - 0.0031 inch)
2nd ring : 0.030 - 0.070 mm (0.0012 - 0.0028 inch)
Oil ring : 0.065 - 0.135 mm (0.0026 - 0.0053 inch)
Limit:
Top ring : 0.11 mm (0.0043 inch)
2nd ring : 0.10 mm (0.0039 inch)
^ If the measured value exceeds the limit, replace piston ring, and measure again. If it still exceeds the limit, replace piston also.

PISTON RING END GAP





^ Make sure that cylinder bore inner diameter is within the specification. Refer to Cylinder Bore Inner Diameter.
^ Lubricate with new engine oil to piston and piston ring, and then insert piston ring until middle of cylinder with piston, and mea sure piston ring end gap with a feeler gauge.
Standard:
Top ring : 0.21 - 0.31 mm (0.0083 - 0.0122 inch)
2nd ring : 0.32 - 0.47 mm (0.0126 - 0.0185 inch)
Oil ring (rail ring) : 0.20 - 0.60 mm (0.0079 - 0.0236 inch)
Limit:
Top ring : 0.54 mm (0.0213 inch)
2nd ring : 0.65 mm (0.0256 inch)
Oil ring (rail ring) : 0.95 mm (0.0374 inch)
^ If the measured value exceeds the limit, replace piston ring, and measure again. If it still exceeds the limit, re-bore cylinder inner wall and use oversized piston and piston rings.