Piston Ring, Engine

Piston ring
Piston ring gap
Top ring
STD 0.20 - 0.25 mm (0.0079 - 0.0098 inch)
Limit 1.0 mm (0.039 inch)
Second ring
STD 0.37 - 0.52 mm (0.015 - 0.020 inch)
Limit 1.0 mm (0.039 inch)
Oil ring
STD 0.20 - 0.50 mm (0.0079 - 0.020 inch)
Limit 1.5 mm (0.059 inch)
Clearance between piston ring and piston ring groove
Top ring
STD 0.040 - 0.080 mm (0.0016 - 0.0031 inch)
Limit 0.15 mm (0.0059 inch)
Second
STD 0.030 - 0.070 mm (0.0012 - 0.0028 inch)
Limit 0.15 mm (0.0059 inch)