Piston Ring, Engine

End Gap
Nominal [1]
Top Ring 0.13-0.26 mm (0.005118-0.010236 inch)
Second Ring 0.30-0.55 mm (0.011811-0.021654 inch)
Oil Ring Rail 0.15-0.66 mm (0.005910-0.025984 inch)
Maximum
Top Ring 0.75 mm (0.029528 inch)
Second Ring 0.75 mm (0.029528 inch)
Oil Ring Rail 1.25 mm (0.049213 inch)
Side Clearance, Minimum-Maximum
Top Ring 0.040-0.090 mm (0.001575-0.001610 inch)
Second Ring 0.030-0.080 mm (0.001181-0.003150 inch)
Service Limit 0.015 mm (0.000591 inch)
Oil Ring Snug Fit

[1] Specification in gauge.