Piston Ring: Testing and Inspection

1. 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.
2. Check for clearance between the piston ring and ring groove. If the limit is exceeded, replace the ring or piston, or both.
Standard value
Number 1: 0.03 - 0.07 mm (0.0012 - 0.00028 inch)
Number 2: 0.02 - 0.06 mm (0.0008 - 0.0024 inch)
Limit: 0.1 mm (0.0039 inch)





3. Insert the piston ring into the cylinder bore. Force the ring down with a piston, the piston 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 is excessive, replace the piston ring.
Standard value:
Number 1: 0.20 - 0.40 mm (0.0098 - 0.0157 inch)
Number 2: 0.40 - 0.55 mm (0.0157 - 0.0217 inch)
Oil Ring: 0.20 - 0.60 mm (0.078 - 0.0236 inch)
Limit:
Number 1 and Number 2: 0.8 mm (0.031 inch)
Oil: 1.0 mm (0.039 inch)