Piston Ring, Engine

Piston ring end gap - compression (top, gauge diameter) a 0.100-0.250 mm (0.0039-0.0098 inch)
Piston ring end gap - compression (bottom, gauge diameter) 0.27-0.42 mm (0.0106-0.0165 inch)
Piston ring end gap - oil ring (steel rail, gauge diameter) 0.15-0.65 mm (0.0059-0.0255 inch)
Piston ring end gap - max compression (top, service limit) 0.50 mm (0.0196 inch)
Piston ring end gap - max compression (bottom, service limit) 0.65 mm (0.0255 inch)
Piston ring end gap - oil max ring (steel rail, service limit) 0.90 mm (0.0354 inch)