Piston Ring, Engine

Piston Rings
Ring end gap
Compression
Bottom (gauge diameter) 0.27-0.42 mm (0.0106-0.0165 in)
Bottom (service limit) 0.65 mm (0.0255 in) max
Top (gauge diameter) (a) 0.100-0.250 mm (0.0039-0.0098 in)
Top (service limit) 0.50 mm (0.0196 in) max
Oil ring
(Steel rail, gauge diameter) 0.15-0.65 mm (0.0059-0.0255 in)
(Steel rail, service limit) 0.90 mm (0.0354 in) max
Ring groove width
Compression
Bottom 1.530-1.545 mm (0.0602-0.0608 in)
Top 1.230-1.245 mm (0.0484-0.0490 in)
Oil ring 3.030-3.055 mm (0.1192-0.0120 in)
(a) Specification 82.4 mm (3.2441 in) diameter gauge