Engine - Rod And Main Bearing Selection: Overview

REFERENCE ENGINES
NUMBER 017
DATE 05-02-86
MODEL MX, MA

Connecting Rod:

Selection of individual connecting rod bearings and main bearings for late model 5M-GE engines (approximately 6/84 production) is accomplished as follows:

1. Connecting rod bearing selection
1) Locate the rod bearing size numbers on the crankshaft counter weights as illustrated below:

Individual Rod Sizing Number:

2) Identify the individual rod sizing number on each connecting rod cap.
Note: Be sure to use the number in the location illustrated above. There are other numbers on the rod that do not apply to bearing size.

Rod Bearing Number:

3) The correct bearing number is obtained by adding the crankshaft number and the rod cap number together.
4) After selecting the proper bearing, check the oil clearance with plastigauge as outlined in the repair manual.


Clearance specs.


Standard clearance: 0.021 - 0.053 mm (0.0008 - 0.0021 in.)
Maximum clearance: 0.08 mm (0.0031 in.)


If oil clearance is not within specification, a different size bearing must be selected and oil clearances rechecked. If correct clearance cannot be obtained with any of the 5 bearings, the crank shaft must be replaced or ground.