Piston Ring Replacement

Remove the piston from the engine block. Using a ring expander (A), remove the old piston rings (B). Clean all ring grooves thoroughly with a squared-off broken ring or ring groove cleaner with a blade to fit the piston grooves. The top and 2nd ring grooves are 1.2 mm (0.05 in.) wide. The oil ring groove is 2.0 mm (0.08 in.) wide (K20Z2 engine), 2.5 mm (0.10 in.) wide (K24A3 engine). File down a blade if necessary. Do not use a wire brush to clean the ring grooves, or cut the ring grooves deeper with the cleaning tools. 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. Measure the piston ring end-gap (B) with a feeler gauge: If the gap is too small, check to see if you have the proper rings for your engine. If the gap is too large, recheck the cylinder bore diameter against the wear limits. If the bore is over the service limit, the engine block must be rebored.
   Piston Ring End-Gap
   Standard (New): | 0.20−0.35 mm (0.008−0.014 in.)
   Service Limit: | 0.60 mm (0.024 in.)
   K20Z2 Engine:
   Standard (New): | 0.40−0.55 mm (0.016−0.022 in.)
   Service Limit: | 0.70 mm (0.028 in.)
   K24A3 Engine:
   Standard (New): | 0.50−0.65 mm (0.020−0.026 in.)
   Service Limit: | 0.75 mm (0.030 in.)
   K20Z2 Engine:
   Standard (New): | 0.25−0.65 mm (0.010−0.026 in.)
   Service Limit: | 0.75 mm (0.030 in.)
   K24A3 Engine:
   Standard (New): | 0.20−0.70 mm (0.008−0.028 in.)
   Service Limit: | 0.80 mm (0.031 in.)

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

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): | 0.045−0.070 mm (0.0018−0.0028 in.)
   Service Limit: | 0.13 mm (0.005 in.)
   Second Ring Clearance
   Standard (New):
   K20Z2 egine: | 0.030−0.055 mm (0.0012−0.0022 in.)
   K24A3 engine: | 0.040−0.065 mm (0.0016−0.0026 in.)
   Service Limit: | 0.13 mm (0.005 in.)