Piston Ring: Testing and Inspection

GENERAL
Check the piston ring for damage, excessive wear, and breakage and replace if defects are evident. If the piston has been replaced with a new one, the piston rings must also be replaced with new ones.

SIDE GROOVE CLEARANCE
Check for the clearance between the piston ring and ring groove. If No. 1 ring is not within 0.04 - 0.08 mm (0.0016 - 0.0031 inch) or No. 2 ring is not within 0.02 - 0.06 mm (0.0008 - 0.0024 inch), replace the ring or piston, or both. The wear limit is 0.1 mm (0.004 inch).





END GAP
Install the piston ring into the cylinder bore. Force it down with a piston, its crown being in contact with the ring, to correctly position it at right angles to the cylinder wall. Then, measure the end gap with a feeler gauge. If the ring gap for No. 1 is not within 0.25 - 0.35 mm (0.0098 - 0.0138 inch), No. 2 is not within 0.40 - 0.55 mm (0.0157 - 0.0217 inch) or the oil side rails are not within 0.10 - 0.40 mm (0.0039 - 0.0157 inch), replace the piston ring. The wear limit is 0.8 mm (0.031 inch) for No. 1 and No. 2 compression rings and 1.0 mm (0.039 inch) for the oil side rails.