Piston Ring Replacement

Remove the piston from the engine block (see CRANKSHAFT AND PISTON REMOVAL ).
Using a ring expander (A), remove the old piston rings (B).

Fig 1: Removing Piston Rings Using Ring Expander
Courtesy of AMERICAN HONDA MOTOR CO., INC.
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.
Using a piston, push a new ring (A) into the cylinder bore 15-20 mm (0.6-0.8 in) from the bottom.

Fig 2: Identifying Cylinder Bore And Piston Ring End-Gap
Courtesy of AMERICAN HONDA MOTOR CO., INC.
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 (see BLOCK AND PISTON INSPECTION ).
If the bore is over the service limit, the engine block must be rebored.

Piston Ring End-Gap

Top Ring:

Standard (New): 0.15-0.30 mm (0.006-0.011 in)

Service Limit: 0.60 mm (0.023 in)

Second Ring:

Standard (New): 0.30-0.42 mm (0.012-0.016 in)

Service Limit: 0.65 mm (0.025 in)

Oil Ring:

Standard (New): 0.10-0.40 mm (0.004-0.015 in)

Service Limit: 0.80 mm (0.031 in)
Install the rings as shown. The top ring (A) has a RC mark, and the second ring (B) has a 2R mark. The manufacturing marks (C) must face upward.

Fig 3: Identifying Top Ring And Second Ring
Courtesy of AMERICAN HONDA MOTOR CO., INC.
After installing a new set of rings, measure the ring-to-groove clearances:
Top Ring Clearance

Standard (New): 0.065-0.090 mm (0.003-0.003 in)

Service Limit: 0.15 mm (0.005 in)

Second Ring Clearance

Standard (New): 0.030-0.055 mm (0.002-0.002 in)

Service Limit: 0.12 mm (0.004 in)

Fig 4: Measuring Ring-To-Groove Clearances
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Rotate the rings in their grooves to make sure they do not bind.
Position the ring end gaps as shown:

Fig 5: Identifying Position Of Ring End Gaps
Courtesy of AMERICAN HONDA MOTOR CO., INC.