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 With Ring Expander
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 to fit the piston grooves.
- The top ring groove is 1.0 mm (0.04 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, push a new ring (A) into the cylinder bore 15-20 mm (0.6-0.8 in.) from the bottom.

Fig 2: Identifying Piston Ring Clearance
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 (0.006-0.012 in.)

Service Limit: 0.50 mm (0.020 in.)

Second Ring:

Standard (New): 0.35-0.50 mm (0.014-0.020 in.)

Service Limit: 0.70 mm (0.028 in.)

Oil Ring:

Standard (New): 0.20-0.70 mm (0.008-0.028 in.)

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

Fig 3: Installing Rings With Manufacturing Marks
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: Positioning 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): 0.055-0.080 mm (0.0022-0.0031 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: 0.13 mm (0.005 in.)

Fig 5: Measuring Ring-To-Groove Clearances
Courtesy of AMERICAN HONDA MOTOR CO., INC.