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Piston Ring Replacement

  1. Using a ring expander (A), remove the old piston rings (B).
  1. Clean all the ring grooves thoroughly with a squared-off broken ring, or a ring groove cleaner with a blade to fit the piston grooves. File down the blade, if necessary. The top and second ring grooves are 1.0 mm (0.04 in.) wide, and the oil ring groove is 2.0 mm (0.08 in.) wide. Do not use a wire brush to clean the ring grooves, or cut the ring grooves deeper with the cleaning tool.
    NOTE: If the piston is to be separated from the connecting rod, do not install new rings yet.

  1. Using a piston, push a new ring (A) into the cylinder bore 15−20 mm (0.6−0.8 in.) from the bottom.
  1. Measure the piston ring end-gap (B) with a feeler gauge:
    Piston Ring End-Gap
    Top Ring:
    Standard (New):
    0.15−0.30 mm (0.006−0.012 in.)
    Service Limit:
    0.60 mm (0.024 in.)
    Second Ring:
    Standard (New):
    0.30−0.42 mm (0.012−0.017 in.)
    Service Limit:
    0.65 mm (0.026 in.)
    Oil Ring:
    Standard (New):
    0.20−0.70 mm (0.008−0.028 in.)
    Service Limit:
    0.80 mm (0.031 in.)

  1. Install the top ring and the second ring as shown. The top ring (A) has a R mark, and the second ring (B) has a 2R mark. The manufacturing marks (C) must be face upward.
  1. Rotate the rings in their grooves to make sure they do not bind.

  1. Position the ring end gaps as shown:

  1. After installing a new set of rings, measure the ring-to-groove clearances:

    Top Ring Clearance

    Standard (New):
    0.065−0.090 mm (0.0026−0.0035 in.)
    Service Limit:
    0.15 mm (0.006 in.)

    Second Ring Clearance

    Standard (New):
    0.030−0.055 mm (0.0012−0.0022 in.)
    Service Limit:
    0.12 mm (0.005 in.)