Connecting Rod Bearing: Service and Repair

STANDARD PROCEDURE - CONNECTING ROD BEARING AND CRANKSHAFT JOURNAL CLEARANCE





1. Measure the connecting rod bore with bearings removed and the bolts tightened to 100 Nm (73 ft. lbs.) torque.
2. Measure the connecting rod bore with the bearings installed and the bolts tightened to 100 Nm (73 ft. lbs.) torque.

Measure within 20° arc from each side of the parting line. Also measure 90° from parting line.

Record the smallest and largest diameter.

Measure the diameter of the rod journal at the location shown. Calculate the average diameter for each side of the journal.

Determine minimum bearing clearance by calculating the differance between the smallest connecting rod bore diameter with the bearing installed and the average diameter for each side of the crankshaft connecting rod journal. See charts below.

Determine the maximum bearing clearance by calculating the difference between the largest connecting rod bore diameter and the average diameter with the bearing installed for each side of the crankshaft connecting rod journal. See charts below.

If the crankshaft is within limits, replace the bearing. If the crankshaft is out of limits, grind the crankshaft to the next smaller size and use oversize rod bearings.

CONNECTING ROD BORE DIAMETER LIMITS






CONNECTING ROD JOURNAL DIAMETER LIMITS