Piston and Connecting Rod
REMOVAL
Connecting Rod Cap
NOTE: Keep the bearings in order with their corresponding connecting rods (according to cylinder numbers) for proper reassembly.
1. Remove the connecting rod cap nuts and then remove the caps and the big end lower bearing.
2. Push each piston-connecting rod assembly toward the top of the cylinder.
Piston Pin Removal and Installation Procedures
1. Use the special tools (09234-33001) to disassemble and reassemble the piston and connecting rod.
2. Place the proper insert in the fork (09234-33003) of the tool. Position the insert between the connecting rod and the piston.
3. Insert the proper removal tool through the hole in the arch of the tool.
NOTE: Center the piston, rod and pin assembly with the removal arbor.
4. Press the piston pin out of the connecting rod.
5. Install proper pin guide through piston and into connecting rod. Hand tap pin guide into piston for proper retention. Drop piston pin into the other side of the piston.
NOTE: The pin guide centers the connecting rod in the piston. When the piston, connecting rod, piston pin and pin guide assembly are positioned on the fork of the tool, the pin guide will also center this assembly in the tool. If a pin guide that is too small is used, the piston assembly will not be located centrally in the tool, and damage may occur to the fork and/or the insert of the tool.
6. Install piston assembly onto fork assembly of tool. Tool will support connecting rod at the piston pin. Be sure piston assembly is slid onto the fork until the pin guide contacts the fork insert.
7. Adjust the installing arbor to the proper length by turning the numbered sleeve on the lettered shaft until the specified alphanumeric setting from the application chart is obtained. Turn knurled nut to lock numbered sleeve on shaft.
8. Insert the installing arbor through the hole in the arch of the tool. Press piston pin into the connecting rod until the sleeve on the installing arbor contacts the top of the tool arch. The pin guide will fall out of the connecting rod as the piston pin is pressed in.
CAUTION: Do not exceed 5,000 pounds of force when stopping the installing arbor sleeve against the arch.
INSPECTION
Piston and Piston Pin
1. Check each piston for scuffing, scoring, wear, and other defects.
Replace any piston that is defective.
2. Check each piston ring for breakage, damage, and abnormal wear. Replace the defective rings. When the piston requires replacement, its rings also should be replaced.
3. Check the piston pin fit in the piston pin hole. Replace any piston and pin assembly that is defective.
The piston pin must push into the pin hole by hand at room temperature.
Piston Rings
1. Measure the piston ring side clearance. If the measured value exceeds the service limit, insert a new ring in a ring groove to measure the side clearance. If the clearance still exceeds the service limit, replace the piston and rings together. If it is less than the service limit, replace the piston rings only.
Piston ring side clearance
No.1 0.04 - 0.08 mm (0.002 - 0.003 inch)
No.2 0.03 - 0.07 mm (0.001 - 0.003 inch)
[Limit]
No.1, No.2 0.1 mm (0.004 inch)
2. To measure the piston ring end gap, insert a piston ring into the cylinder bore. Correctly position the ring into the cylinder by gently pushing it down with a piston. Remove the piston and measure the end gap with a feeler gauge. If the gap is not within the service limit, replace the piston ring.
When replacing the ring only, without correcting the cylinder bore, check the end gap with the ring positioned at the bottom of the ring travel.
When replacing a ring, be sure to use a ring of the same size.
NOTE: The mark can be found on the upper side of the ring next to the end.
Connecting Rods
1. When reinstalling, make sure that cylinder numbers put on the connecting rod and cap at disassembly match.
When a new connecting rod is installed, make sure that the notches for holding the bearing in place are on the same side.
2. Replace the connecting rod if it is damaged on the thrust faces at either end. Also if step wear or a severely rough surface of the inside diameter of the small end is apparent, the rod must be replaced as well.
3. Using a connecting rod aligning tool, check the rod for bend and twist. If the measured value is close to the repair limit, correct the rod by a press. Any connecting rod that has been severely bent or distorted should be replaced.
Allowable bend of connecting rod 0.05 mm/100 mm (0.002 in./3.94 inch) or less
Allowable twist of connecting rod 0.1 mm/100 mm (0.004 in./3.94 inch) or less
INSTALLATION
1. Install the spacer.
2. Install upper side rail. To install side rail, first put one end of side rail between piston ring groove and spacer, hole it down firmly, and then press down the portion which is to be inserted into groove with a finger as illustrated.
NOTE: Do not use piston ring expander when installing side rail.
3. Install lower side rail by same procedure as Step 2.
4. Using piston ring expander, install No.2 piston ring.
5. Install No.1 piston ring.
6. Apply engine oil around piston and piston rings.
7. Position each piston ring end gap as for apart from neighboring gaps as possible. Make sure that gaps are not positioned in thrust and pin directions.
8. Hold piston rings firmly in a piston ring compressor as they are inserted into cylinder.
9. Make sure that front mark of piston and front mark (identification mark) of connecting rod are directed toward front of engine.
10. When connecting rod cap is installed, make sure that cylinder numbers put on rod and cap at disassembly match.
11. When new connecting rod is installed, make sure that notches for holding bearing in place are on same side.
12. Tighten the connecting rod cap nuts.
Tightening torque
Connecting rod cap nuts 50 - 53 Nm (500 - 530 kg.cm, 37 - 39 ft. lbs.)
13. Check connecting rod side clearance.
Side clearance 0.10 - 0.25 mm (0.004 - 0.010 inch)
Limit 0.4 mm (0.016 inch)