Connecting Rod: Service and Repair
DISASSEMBLY
Connecting Rod Cap
CAUTION: Keep the bearings in order with their corresponding connecting rods (according to cylinder numbers) for proper reassembly.
1. Remove the connecting rod cap nuts, 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.
CAUTION: 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 pinch Be sure to slide the piston assembly 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 alpha-numeric 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 inch
CAUTION: Do not exceed 5000 pounds of force when stopping the installing arbor sleeve against the arch.
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, its rings should also 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 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.
Standard value:
Piston ring side clearance: No1 0.03 - 0.07 mm (0.0012 - 0.0028 inch)
Limit:
No2: 0.1 mm (0.004 inch)
No3: 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.
Piston Ring End Gap
Standard value:
No. 1: 0.30 - 0.40 mm (0.0118 - 0.0157 inch)
No. 2: 0.45 - 0.60 mm ( 0.0138 - 0.0197 inch)
Oil ring side rail: 0.2 - 0.6 mm (0.0079 - 0.0179 inch)
Limit:
No. 1: 0.8 mm (0.031 inch)
No. 2: 0.8 mm ( 0.031 inch)
Oil ring side rail: 1.0 mm (0.039 inch)
When replacing the ring with out correcting the cylinder bore, check the gap with the ring positioned at the low part or cylinder that is less worn.
Piston ring service size and mark
STD: None
0.25mm (0.010 inch) O.S: 25
0.50mm (0.020 inch) O.S: 50
0.75mm (0.030 inch) O.S: 75
1.00mm (0.039 inch) O.S: 100
NOTE: The mark can be found on the upper side of the ring next to the end
Connecting Rods
1. When the connecting rod cap is installed, make sure that cylinder numbers marked on rod end 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 at either end of the thrust faces, if it has a step wear in, or if the surface of the inside diameter of the small end is severely rough.
REASSEMBLY
1. Install the spacer.
2. Install the upper side rail. To install the side rail, first put one end of the side rail between the piston ring groove and spacer, hold it down firmly, and press down with a finger on the portion to be inserted into the groove (as illustrated).
CAUTION: Do not use a piston ring expander when installing side rail.
3. Install the lower side rail using the procedure described in Step 2.
4. Apply engine oil around the piston and piston rings.
5. Using a piston ring expander, install the No.2 piston ring.
6. Install the No. 1 piston ring.
7. Position each piston ring end gap as far apart from neighboring gaps as possible. Make sure that the gaps are not positioned in the thrust and pin directions.
8. Hold piston rings firmly in a piston ring compressor as they are inserted into cylinder.
9. Install the upper main bearings in the cylinder block.
10. Install the lower main bearings in the main bearing caps.
CAUTION: Install the bearing with the oil hole in the block.
11. Install the thrust washers in the No. 3 main bearing cap with the oil grooves facing outward.
12. Make sure that the front mark of the piston and the front mark (identification mark) of the connecting rod are directed toward the front of the engine.
13. When the connecting rod cap is installed, make sure that the cylinder numbers put on the rod and cap at disassembly match.
14. When a new connecting rod is installed, make sure that the notches for holding the bearing in place are on the same side.
15. Tighten the connecting rod cap nuts.
Tightening torque:
Connecting rod cap nuts: 50 - 53 Nm (500 - 530 kgs.cm, 36 - 38 ft. lbs.)
16. Check the bearing clearance as follows:
1) Remove oil and dirt from the bearings and journals.
2) Cut plastigauge to the same length as the width of the bearing and place it in parallel with the journal, avoiding the oil holes.
3) Install the bearing and cap. Tighten to the specified torque. During this operation, do NOT turn the crankshaft.
4) Remove the cap, measure the width of the plastigauge at the widest part by using the scale printed on the plastigauge package.
Standard value: 0.016 - 0.046 mm (0.0006 - 0.0018 inch)
Limit: 0.1 mm (0.0039 inch)
17. Check the connecting rod side clearance.
Standard value: 0.10 - 0.25 mm (0.0039 - 0.0098 inch)
Limit: 0.4 mm (0.016 inch)