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 to ring and piston ring Top groove
Top ring
STD 0.040-0.080 mm (0.0016-0.0031 inch)
Limit 0.15 mm (0.0059 inch)
Second ring
STD 0.030-0.070 mm (0.0012-0.0028 inch)
Limit 0.15 mm (0.0059 inch)