Crankshaft Main Bearings-Fitting

MAIN BEARING JOURNAL MEASUREMENT





Fig. 21

Measure the journal outside diameter (Fig. 21). If the clearance exceeds the specifications limit, replace the main bearing(s), and if necessary, replace the crankshaft. Refer to Engine Specifications.

PLASTIGAGE MEASUREMENT
1. Remove oil from journal and bearing shell.
2. Install crankshaft.





Fig. 22

3. Cut plastigage to same length as width of the bearing and place it in parallel with the journal axis (Fig. 22).
4. Install the main bearing cap carefully and tighten the bolts to specified torque.

CAUTION: Do not rotate crankshaft or the plastigage will be smeared.





Fig. 23

5. Carefully remove the bearing cap and measure the width of the plastigage at the widest part using the scale on the plastigage package (Fig. 23). Refer to Engine Specifications for proper clearance. Also see Measuring Main and Connecting Rod Bearing Clearances in Standard Service Procedures.

CRANKSHAFT BEARING INSTALLATION
When replacing the bearings, select and install the proper bearing by using the following procedure.





Fig. 25

1. Measure the crankshaft journal diameter and confirm its classification from the Main Journal Size Identification Chart. In the case of a bearing supplied as a service part, the identification is embossed at the position show in (Fig. 25).





Fig. 24

NOTE: Service Replacement parts have identification marks, but factory-assembled parts have no identification marks. Service crankshaft identification will have marks at counterweights (Fig. 24).





MAIN JOURNAL SIZE IDENTIFICATION





Fig. 26

2. The identification mark for the diameter of the cylinder block bearing bore is embossed as shown in (Fig. 26), starting from the # 1 mark at the front of the engine.
3. Select and install the bearings according to these marks. Using the chart below, select the proper bearing by using the markings on the crankshaft and block. For a example:
a. If the crankshaft journal outer diameter is 60.000 mm (2.3622 inch), the service part classification will be "0" and the identification mark will be "O".





CYLINDER BLOCK IDENTIFICATION MARK

b. If the identification mark for the cylinder block main bore is "II", select the bearing "2" according the chart below.