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 Old Piston Rings
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Clean all ring grooves thoroughly with a squared-off broken ring or ring groove cleaner with a blade that fits the piston grooves.
The top ring groove is 1.5 mm (0.06 in.) wide. The 2nd ring groove is 1.2 mm (0.05 in.) wide. The oil ring groove is 2.0 mm (0.08 in.) wide.

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

Fig 2: Pushing Ring Into Cylinder Bore
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 beyond the service limit, the engine block must be rebored.
Piston Ring End-Gap

Top Ring:

Standard (New): 0.20-0.30 mm (0.008-0.012 in.)

Service Limit: 0.60 mm (0.024 in.)

Second Ring:

Standard (New): 0.40-0.50 mm (0.016-0.020 in.)

Service Limit: 0.75 mm (0.030 in.)

Oil Ring:

Standard (New): 0.10-0.30 mm (0.004-0.012 in.)

Service Limit: 0.80 mm (0.031 in.)
Install the top ring and the second ring as shown. The top ring (A) has a 1N mark and the second ring (B) has a 2N mark. The manufacturing marks (C) must be face upward.

Fig 3: Identifying Installation Position Of Piston Rings
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 4: Identifying Ring End Gaps
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): 0.045-0.090 mm(0.0018-0.0035 in.)

Service Limit: 0.13 mm (0.005 in.)

Second Ring Clearance

Standard (New): 0.040-0.065 mm (0.0016-0.0026 in.)

Service Limit: 0.13 mm (0.005 in.)

Oil Ring Clearance

Standard (New): 0.020-0.050 mm (0.0008-0.0020 in.)

Service Limit: 0.08 mm (0.003 in.)

Fig 5: Measuring Ring-To-Groove Clearances

Courtesy of AMERICAN HONDA MOTOR CO., INC.