Removal and Replacement

OVERVIEW





Fig. 113

Bearing caps are not interchangeable and are marked to insure correct assembly (Fig. 113). Upper and lower bearing halves are NOT interchangeable.

CRANKSHAFT MAIN JOURNALS
The crankshaft journals should be checked for excessive wear, taper and scoring. Limits of taper or out-of-round on any crankshaft journals should be held to 0.015 mm (0.0006 inch). Journal grinding should not exceed 0.305 mm (0.012 inch) under the standard journal diameter. DO NOT grind thrust faces of Number 2 main bearing. DO NOT nick crank pin or bearing fillets. After grinding, remove rough edges from crankshaft oil holes and clean out all passages.

CAUTION: With a forged steel crankshaft it is important that the final paper or cloth polish after any journal regrind be in the same direction as normal motion in the engine.





Fig. 114

The crankshaft thrust is controlled with thrust washers located at the upper No. 2 main bearing bulk head (Fig. 114). All bearing cap bolts removed during service procedures are to be cleaned and oiled before installation. Bearing shells are available in standard and the following undersized: 0.025 mm (0.001 inch) and 0.254 mm (0.010 inch). Never install an undersized bearing that will reduce clearance below specifications.

REMOVAL
1. Remove oil pan, pick-up tube, and windage tray. Identify bearing caps before removal.





Fig. 115

2. Remove bearing caps one at a time. Remove upper half of bearing by inserting Special Main Bearing Tool C-3059 (Fig. 115) into the oil hole of crankshaft.
3. Slowly rotate crankshaft clockwise, forcing out upper half of bearing shell.

INSTALLATION

CAUTION: Main bearings are select fit. Refer to Engine, Service Procedures, Crankshaft Main Bearing Fitting for proper bearing selection.

NOTE: Only one main bearing should be selectively fitted while all other main bearing caps are properly tightened.

When installing a new upper bearing shell, slightly chamfer the sharp edges from the plain side.
1. Lubricate main bearing with clean engine oil.
2. Start bearing in place, and insert Main Bearing Tool C-3059 into oil hole of crankshaft (Fig. 115).
3. Slowly rotate crankshaft counterclockwise sliding the bearing into position. Remove Special Main Bearing Tool C-3069.

NOTE: Lubricate main bearing cap bolts with engine oil before installation.

4. Lubricate and install lower bearing half and main cap. Tighten bolts finger tight.
5. For installing thrust washers at the No. 2 main bearing location, use the following procedure:





Fig. 116

a. Move crankshaft forward to limit of travel. Lubricate and install the front thrust washer by rolling the washer onto the machined shelf between the No. 2 upper main bulk head and crankshaft thrust surface (Fig. 116).
b. Move crankshaft rearward to limit of travel. Lubricate and install the rear thrust washer by rolling the washer onto the machined shelf between the No. 2 upper main bulk head and crankshaft thrust surface.
The main bearing cap bolts must be tightened in the proper sequence. First the inner main cap bolts, secondly the windage tray bolts, lastly the main cap tie (horizontal) bolts.
6. Install each main bearing cap and tighten inner bolts finger tight.
7. Tighten inner main bearing cap bolts to 20 Nm + 1/4 turn (15 ft. lbs. + 1/4 turn).
8. Measure crankshaft end play.
9. Install windage tray. Lubricate bolts with engine oil and tighten to 27 Nm + 1/4 turn (20 ft. lbs. + 1/4 turn).
10. Install the main cap tie (horizontal) bolts and tighten to 28 Nm (250 in. lbs.).
11. Install oil pump pick-up tube and oil pan.
12. Fill engine crankcase with proper oil to correct level.