Piston Ring, Engine

Compression Ring Groove Clearance:
Production:
Top 0.030-0.070 mm (0.0012-0.0027 inch)
2nd 0.040-0.080 mm (0.0015-0.003 inch)
Service Limit:
Top 0.030-0.090 mm (0.0012-0.0035 inch)
2nd 0.040-0.100 mm (0.0015-0.004 inch)

Compression Ring Gap [1]:
Production:
Top 0.25-0.51 mm (0.010-0.020 inch)
2nd 0.46-0.66 mm (0.018-0.026 inch)
Service:
Top 0.25-0.65 mm (0.010-0.025 inch)
2nd 0.46-0.90 mm (0.018-0.035 inch)

Oil Ring Groove Clearance:
Production 0.051-0.17 mm (0.002-0.006 inch)
Service 0.051-0.22 mm (0.002-0.009 inch)

Oil Ring Gap [1]:
Production 0.25-0.76 mm (0.010-0.030 inch)
Service 0.25-0.89 mm (0.010-0.035 inch)

[1] End gap measured in cylinder bore.