Connecting Rod: Service and Repair
DISASSEMBLY
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 of the tool. Insert the position 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 (refer to application chart) through piston and into connecting rod. Hand and 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 too small a pin guide used, the piston assembly will not be located centrally in the tool, and damage may occur to the fork and/or 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. Adjust the installing arbor to the proper length by turning the numbered sleeve on the lettered shaft until the specified alpha-numeric setting from the application chart is obtained. Turn knurled nut to lock numbered sleeve on shaft.
7. 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 5000 pounds of force when stopping the installing arbor sleeve against the arch.
NOTE:
Convex depth: 1.8L: 2.05-2.25 mm (0.080-0.088 inch)
INSPECTION
Piston and Piston Pins
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, also replace the rings
3. Check the piston pin fit in the piston pin hole. Replace any defective piston and pin assembly that is defective. The piston pin must be smoothly pressed by hand into the pin hole (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 only the piston rings.
Piston ring side clearance
Standard Value:
No. 1: 0.04 - 0.085 mm (0.0016 - 0.0031)
No. 2: 0.04 - 0.085 mm (0.0016 - 0.0031 inch)
Limit:
No. 1: 0.1 mm (0.004 inch)
No. 2: 0.1 mm ( 0.004 inch)
2. To measure the piston ring end gap, insert a piston ring into the cylinder bore. Position the ring at right angles to the cylinder wall by gently pressing it down with a piston. Measure the gap with a feeler gauge. If the gap exceeds the service limit, replace the piston ring.
When replacing the ring without correcting the cylinder bore, check the gap with the ring positioned at the bottom of the ring travel.
When replacing a ring, use a ring of the same size.
Piston ring service size and mark:
STD: None
0.25 mm (0.010 inch) O.S.: 25
0.50 mm (0.020 inch) O.S.: 50
0.75 mm (0.030 inch) O.S.: 75
1.00 mm (0.039 inch) O.S.: 100
NOTE: The mark can be found on the upper side of the ring next to the end.
INSPECTION
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 (0.0020 in./3.94 inch) or less
Allowable twist of connecting rod: 0.1 mm/100 mm (0.0039 in./3.94 inch) or less
REASSEMBLY
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, hold it down firmly, then press down with your finger the portion to be inserted into groove 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 far apart from neighboring gaps as possible. Make sure that gaps are not positioned in side rail thrust and pin directions.
8. Hold piston rings firmly in a piston ring compressor as you insert them 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 can nuts.
Connecting rod cap nuts: 50 - 53 Nm ( 500 - 530 kg.cm, 36 - 39 ft. lbs.)
13. Check connecting rod side clearance.
Connecting rod side clearance:
Standard value: 0.10 - 0.25 mm (0.004 - 0.0098 inch)
Limit: 0.4 mm (0.0157 inch)