Diesel Data: Automotive Repair

Connecting Rod Bearing: Service and Repair






CONNECTING RODS AND BEARINGS





CAUTION: The bearing caps are not interchangeable and should be paint marked or scribed at removal to insure correct assembly. DO NOT use a metal stamp.

The bearing shells must be installed with the tangs inserted into the machined grooves in the rods and caps. Install cap with the tangs on the same side as the rod.

Fit all rods on one bank until complete.

Limits of out-of-round on any crankshaft journals should be held to 0.008 mm (0.0003 in.). Bearings are available in standard, 0.025 mm (0.001 in.), and 0.254 mm (0.010 in.) undersizes. Install the bearings in pairs. Do not use a new bearing half with an old bearing half. Do not file the rods or bearing caps.

1. For measuring main bearing clearance and connecting rod bearing clearance use plastigage. For more information on using plastigage Procedures. Refer to Engine Specifications for bearing clearance specifications Engine Specifications.

NOTE: The rod bearing bolts should be examined before reuse. If the threads are necked down the bolts must be replaced.

CONNECTING ROD BOLTS










1. Examine connecting rod bolts for stretching (1). Stretching (1) can be checked by holding a scale or straight edge against the threads. If all the threads do not contact the scale the bolt must be replaced.
2. Before installing the bolts the threads should be cleaned and inspected.
3. Install clean bolts finger tight. Then alternately torque each bolt to assemble the cap properly.
4. Tighten the connecting rod cap bolts to specification. . Engine Specifications

CONNECTING ROD SIDE CLEARANCE





1. Mount a dial indicator to a stationary point on engine. Locate probe perpendicular to and resting against the connecting rod cap being checked. Move connecting rod all the way to rear of its travel. Zero the dial indicator. Move connecting rod forward to limit of travel and read the dial indicator. Compare measurement to specification listed in engine specifications . Engine Specifications Repeat procedure for each connecting rod. Turn crankshaft for connecting rod accessibility.