Piston Rings

1. Measure the piston ring side clearance. If the measured value exceeds the service limit, insert a new ring in a 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 the piston rings only.

   [Standard value]

   Piston ring side clearance :

   No. 1 : 0.03-0.07 mm (0.0012-0.0028 in.)

   No. 2 : 0.02-0.06 mm (0.0008-0.0024 in.)

   [Limit] : 0.1 mm (0.004 in.)

   Fig 1: Checking Piston Ring Side Clearance

   Courtesy of KIA MOTORS AMERICA, INC.
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 dimension]

No. 1 : 0.25-0.35 mm (0.0098-0.0138 in.)

No. 2 : 0.40-0.55 mm (0.0157-0.0216 in.)

Oil ring side rail : 0.10-0.40 mm (0.0039-0.0157 in.)

[Limit]

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

Oil ring side rail : 1.0 mm (0.039 in.)

Fig 2: Checking Piston Ring End Gap

Courtesy of KIA MOTORS AMERICA, INC.