Piston Rings

1. Measure the piston ring side clearance. If the measured value exceeds the service limit, insert a new ring in the ring groove to measure the side clearance. If the clearance still exceeds the service limit, replace the piston and rings together. If it is less than the service limit, replace only the piston rings.

   Piston ring side clearance 

   No.1 : 0.04 ~ 0.08 mm (0.0016 ~ 0.0031 in.)

   No.2 : 0.03 ~ 0.07 mm (0.0012 ~ 0.0028 in.)

   [Limit]

   No.1 : 0.1 mm (0.004 in.)

   No.2 : 0.1 mm (0.004 in.)

2. To measure the piston ring end gap, insert a piston ring into the cylinder bore. Position the ring at right angles to the cylinder wall by gently pressing it down with a piston. Measure the gap with a feeler gauge. If the gap exceeds the service limit, replace the piston ring.

Piston ring end gap 

[Standard dimensions]

No.1 : 0.20 ~ 0.35 mm (0.0079 ~ 0.0138 in.)

No.2 : 0.37 ~ 0.52 mm (0.0146 ~ 0.0205 in.)

[Limit]

No.1, No.2 : 0.8 mm (0.031 in.)

Oil ring side rail : 1.0 mm (0.039 in)

When replacing the ring without correcting the cylinder bore, check the gap with the ring situated at the lower part of cylinder that is less worn out.