Piston, Ring, Pin, and Connecting Rod Removal and Installation

NOTE: enu_12713377_2.0 Where icon is shown, click for further information.


1

8306_3.0_enu_15102524_2.0

enu_12713377_2.0
Detailed information, notes, and precautions
*1
These parts have inspection items.

2. Piston/Connecting Rod Assembly - Remove
1.
If you can feel a ridge of metal or hard carbon around the top of each cylinder, remove it with a ridge reamer (A). Follow the reamer manufacturer's instructions. If the ridge is not removed, it may damage the piston as it is pushed out.
2.
Use the wooden handle of a hammer (A) to drive out the piston/connecting rod assembly (B). Take care not to damage the oil jets or cylinder with the connecting rod.
3.
Reinstall the connecting rod bearings and caps after removing each piston/connecting rod assembly.
NOTE:
Mark each piston/connecting rod assembly with its cylinder number to make sure they are reinstalled in the original order.
The existing number on the connecting rod does not indicate its position in the engine, it indicates the rod bore size.

3. Piston Ring - Remove
1.
Using a ring expander (A), remove the old piston rings (B).
2.
Clean all ring grooves thoroughly with a squared-off broken ring or a ring groove cleaner with a blade to fit the piston grooves.
The top groove is 1.5 mm (0.059 in) wide. The second ring groove is 1.0 mm (0.039 in) wide. The oil ring groove is 2.0 mm (0.079 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.

4. Piston Pin - Remove
1.
Apply new engine oil to the piston pin snap rings (A), and turn them in the ring grooves until the end gaps are lined up with the cutouts in the piston pin bores (B).
NOTE: Take care not to damage the ring grooves.
2.
Remove snap rings (A) from both sides of each piston. Start at the cutout in the piston pin bore. Remove the snap rings carefully so they do not go flying or get lost. Wear eye protection.
3.
Heat the piston and connecting rod assembly to about 158 °F (70 °C).
4.
Remove the piston pin.


NOTE: enu_12713377_2.0 Where icon is shown, click for further information.


1

8306_3.0_enu_15102525_2.0

enu_12713377_2.0
Detailed information, notes, and precautions
*1
These parts have inspection items.

1. Piston Pin - Install
1.
Install a piston pin snap ring (A) only on one side.
2.
Coat the piston pin bore in the piston, the bore in the connecting rod, and the piston pin with new engine oil.
3.
Heat the piston to about 158 °F (70 °C).
4.
Assemble the piston (A) and the connecting rod (B).
NOTE: Align the arrow (C) with the groove (D) direction on the connecting rod as shown.
5.
Install the piston pin (E).
6.
Install the remaining snap ring (F).
7.
Turn the snap rings in the ring grooves until the end gaps are positioned at the bottom of the piston.

2. Piston Ring - Install
1.
Install the piston rings as shown. The top ring (A) has a 1R mark, and the second ring (B) has a 2R mark. The manufacturing marks (C) must be facing upward.
2.
Rotate the rings in their grooves to make sure they do not bind.
3.
Position the ring end gaps as shown.
4.
After installing a new set of rings, measure the ring-to-groove clearances.

3. Piston/Connecting Rod Assembly - Install
1.
Remove the connecting rod bearing caps. Check that the bearing is securely in place.
2.
Apply new engine oil to the piston, the inside of the ring compressor, and the cylinder bore, then attach the ring compressor to the piston/connecting rod assembly.
3.
Position the piston/connecting rod assembly with the arrow (A) facing the cam chain side of the engine block.
4.
Position the piston/connecting rod assembly in the cylinder, and tap it in using the wooden handle of a hammer (A). Push down on the ring compressor (B) to prevent the rings from expanding before entering the cylinder bore.
5.
Stop after the ring compressor pops free, and check the connecting rod-to-rod journal alignment before pushing the piston into place.

Piston Ring End Gap Inspection

1. Piston Ring End Gap - Inspect
1.
Using a piston that has its rings removed, push a new ring (A) into the cylinder bore 15?20 mm (0.59?0.79 in) from the bottom.
2.
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 beyond the service limit, the engine block must be rebored.
Piston Ring End-Gap
Top Ring
Standard (New):
0.20?0.25 mm (0.008?0.009 in)
Service Limit:
0.25 mm (0.009 in)
Second Ring
Standard (New):
0.40?0.55 mm (0.016?0.021 in)
Service Limit:
0.55 mm (0.021 in)
Oil Ring
Standard (New):
0.20?0.50 mm (0.008?0.019 in)
Service Limit:
0.50 mm (0.019 in)

Piston, Pin, and Connecting Rod Inspection

1. Piston Pin - Inspect
1.
Measure the diameter of the piston pin.
Piston Pin Diameter
Standard (New):
21.961?21.965 mm (0.86460?0.86476 in)
Service Limit:
21.951 mm (0.86421 in)
2.
Zero the dial indicator to the piston pin diameter.
3.
Check the difference between the piston pin diameter and the piston pin hole diameter in the piston.
Piston Pin-to-Piston Clearance
Standard (New):
0.002?0.010 mm (0.00008?0.00039 in)
Service Limit:
0.020 mm (0.00079 in)
4.
Measure the piston pin-to-connecting rod clearance.
Piston Pin-to-Connecting Rod Clearance
Standard (New):
0.004?0.016 mm (0.00016?0.00063 in)
Service Limit:
0.020 mm (0.00079 in)

Ring to Groove Clearance Inspection

1. Ring to Groove Clearance - Inspect
1.
Measure the ring-to-groove clearances.
Top Ring Clearance
Standard (New):
0.065?0.090 mm (0.003 in)
Service Limit:
0.11 mm (0.004 in)
Second Ring Clearance
Standard (New):
0.035?0.060 mm (0.002 in)
Service Limit:
0.08 mm (0.003 in)