Procedures

Connecting Rods and Bearings

Special tools, testers and auxiliary items required

• Dial Indicator

Connecting Rod Bearings






The bearing caps are not interchangeable and should be marked at removal to insure correct assembly.

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 taper or out of round on any crankshaft journals should be held to specification limits. Bearings are available in 0.007 mm oversize (0.0003 in oversize), standard, 0.007 mm (0.0003 in) undersize 0.025 mm (0.001 in) undersize, and 0.254 mm (0.010 in undersize. 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.

- For measuring main bearing clearance and connecting rod bearing clearance use plastigage.

Select Fit Rod Bearings






- Connecting rod bearings use "select fit" to achieve improved clearance control. On a new engine, the crankshaft journal is gaged to use a specific bearing size. The grade is indicated on the number 9 counterweight (3) of the crankshaft and listed from left to right with the recommended size.

Select Fit Rod Bearing Grades






Determining Rod Bearing Class






This example shows how to determine the bearing class needed for each rod bearing, assuming that a new crankshaft is being installed in a new or existing engine block. If the code B A B B B C is stamped on the number 9 counterweight of the crankshaft (2), then rod number 1 would require class 2 bearings, rod number 2 would require class 1 bearings, rod number 3 would require class 2 bearings, rod number 4 would require class 2 bearings, rod number 5 would require class 2 bearings, and rod number 6 would require class 3 bearings.

Example: Rod Bearing Selection Data






Connecting Rod Bolts






• The rod bearing bolts should be examined before reuse. If the threads are necked down (2) the bolts must be replaced.

- Examine the connecting rod bolts for stretching. Stretching can be checked by holding a scale or straight edge against the threads. If all the threads (2) do not contact the scale the bolt must be replaced.

- Before installing the bolts the threads should be cleaned and inspected.

- Install clean bolts finger tight. Then alternately tighten each bolt to assemble the cap properly.

- Tighten the connecting rod cap bolts to specifications. Refer to => [ Fastener Tightening Specifications ] Crankshaft, Cylinder Block - Fastener Tightening Specifications.






- Mount a dial indicator to a stationary point on the engine. Locate the probe perpendicular to and resting against the connecting rod cap being checked. Move the connecting rod all the way to rear of its travel (toward the flywheel end of the crank). Zero the dial indicator. Move the connecting rod forward to its limit of travel (toward the pulley end of the crank) and read the dial indicator. Compare the measurement to the specifications, refer to => [ Connecting Rod and Bearing Specifications ] Connecting Rod and Bearing Specifications.