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 only the piston ring only.

   Standard value 

   Piston ring side clearance:

   1. No. 1: 0.03-0.07 mm (0.0012-0.0028 in.)
   2. No. 2: 0.02-0.06 mm (0.0008-0.0024 in.)
   3. Oil ring: 0.06-0.15 mm (0.0024-0.0059 in.)
      Fig 1: Measuring Piston Ring Side Clearance

      Courtesy of HYUNDAI MOTOR CO.
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]

1. No. 1: 0.25-0.35 mm (0.0098-0.0138 in.)
2. No. 2: 0.40-0.55 mm (0.0157-0.0216 in.)
3. Oil ring side rail: 0.10-0.40 mm (0.0039-0.0157 in.)

[Limit]

1. No. 1, No.2: 0.8 mm (0.031 in.)
2. Oil ring side rail: 1.0 mm (0.039 in.)
   Fig 2: Identifying Piston Ring End Gap

   Courtesy of HYUNDAI MOTOR CO.