Connecting Rod: Service and Repair

Fig. 18 Engine Assembly Lubrication Points:

1. Oil all pistons, piston rings and cylinder walls before installation, Fig. 18.
2. Check piston rings for correct gap alignment

Fig. 19 Piston Installation:

3. Install piston ring compressor on piston Fig. 19, then push piston into cylinder block with suitable hammer handle until it is slightly below top of cylinder. Guide connecting rod to avoid damaging crankshaft journal. Ensure indentation notch on top of cylinder is toward front of engine. Repeat for remaining pistons.
4. Measure connecting rod bearing oil clearances. Do not rotate crankshaft during measurement. Crankshaft must be in BTDC position.
a. Remove any foreign material and oil from journals and bearings.
b. Install connecting rod bearing onto connecting rod cap.
c. Position Plastigage atop journal.
d. Apply clean engine oil to threads and seat faces of connecting rod cap bolts, install caps and tighten to specifications.
e. Remove cap and measure Plastigage at each journal at widest point for smaller clearance, and at narrowest point for largest clearance. Standard clearance is 0.0008-0.0015 inch and maximum clearance is 0.0008-0.0026 inch. If clearance exceeds maximum specifications, grind crankshaft and install undersize bearings.
5. Install connecting rod bearings and caps, noting the following:
a. Remove Plastigage from journals and bearings and apply liberal amounts of clean engine oil.
b. Turn crankshaft to bottom of throw and seat piston, then install connecting rod cap. Torque bolts in two steps; first to 25-30 ft. lbs., then to 30-36 ft. lbs.

Fig. 20 Connecting Rod Side Clearance:

6. Measure side clearance of each connecting rod on each journal, Fig. 20. Clearance should be 0.0035-0.0105 inch with a maximum of 0.014 inch. If clearance exceeds maximum, replace connecting rod and cap.