Piston Ring Replacement

1.Remove the piston from the cylinder block.

2.Using a ring expander (A), remove the old piston rings (B).


3.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 (K20A4, K24A1 engines) or 2.8 mm (0.11 in.) wide (K20A5 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.

4.Using a piston, push a new ring (A) into the cylinder bore 15-20 mm (0.6-0.8 in.) from the bottom.


5.Measure the piston ring end-gap (B) with a feeler gauge:

Piston Ring End-Gap:
Top Ring 
Standard (New): 0.20-0.35 mm
(0.008-0.014 in.)
Service Limit: 0.60 mm (0.024 in.) 

Second Ring 
Standard (New): 0.40-0.55 mm
(0.016-0.022 in.)
Service Limit: 0.70 mm (0.028 in.) 

Oil Ring 
K20A4 (Except KY models) engine 
Standard (New): 0.25-0.65 mm
(0.010-0.026 in.)
Service Limit: 0.75 mm (0.030 in.) 

K20A4 (KY models), K20A5, K24A1 engines 
Standard (New): 0.20-0.70 mm
(0.008-0.028 in.)
Service Limit: 0.80 mm (0.031 in.) 

6.Install the top ring and second ring as shown.The top ring (A) has a T or 1R mark and the second ring (B) has a 2T or 2R mark. The manufacturing marks (C) must be facing upward.


7.Rotate the rings in their grooves to make sure they do not bind.

8.Position the ring end gaps as shown:


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

Top Ring Clearance
Standard (New): 
 K20A4 engine: 
 0.035-0.060 mm (0.0014-0.0024 in.) 
 K20A5 engine: 
 0.030-0.055 mm (0.0012-0.0022 in.) 
 K24A1 engine: 
 0.045-0.070 mm (0.0018-0.0028 in.) 
Service Limit: 0.13 mm (0.005 in.) 

Second Ring Clearance
Standard (New): 
 K20A4, K20A5 engine: 
 0.030-0.055 mm (0.0012-0.0022 in.) 
 K24A1 engine: 
 0.050-0.075 mm (0.0020-0.0030 in.) 
Service Limit: 0.13 mm (0.005 in.)