Removal and Installation

MAIN BEARINGS

Main Bearing Cap Identification:

Bearing caps are not interchangeable and should be marked at removal to insure correct assembly. Upper and lower bearing halves are NOT interchangeable. Lower main bearing halves of 1, 3, and 4 are interchangeable. Upper main bearing halves of 1, 3, and 4 are interchangeable.

CRANKSHAFT MAIN JOURNALS

Measuring Crankshaft Journal O.D.:

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 0.025 mm (0.001 inch). Journal grinding should not exceed 0.305 min (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 the nodular cast iron crankshafts used it is important that the final paper or cloth polish after any journal regrind be in the same direction as normal rotation in the engine.

Main Bearing Identification:

Upper and lower number 2 bearing halves are flanged to carry the crankshaft thrust loads and are NOT interchangeable with any other bearing halves in the engine. 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 undersizes: 0.025 min (0.001 inch) and 0.254 mm (0.010 inch). Never install an undersize bearing that will reduce clearance below specifications.

REMOVAL
1. Remove oil pan and identify bearing caps before removal.

Removing And Installing Upper Main Bearing With Special Tool C-3059:

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

INSTALLATION

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. Start bearing in place, and insert Main Bearing Tool C-3059 into oil hole of crankshaft.
2. Slowly rotate crankshaft counterclockwise sliding the bearing into position. Remove Special Main Bearing Tool C-3059.
3. Install each main cap and tighten bolts finger tight.
4. Tighten number 1, 3 and 4 main cap bolts to 41 Nm + 1/4 Turn (30 ft. lbs.+ 1/4 Turn).
5. Rotate the crankshaft until number 6 piston is at TDC.
6. To ensure correct thrust bearing alignment the following procedure must be done:
a. Move crankshaft all the way to the rear of its travel.
b. Then, move crankshaft all the way to the front of its travel.
c. Wedge a appropriate tool between the rear of the cylinder block and rear crankshaft counterweight. This will hold the crankshaft in its most forward position.
d. Tighten the #2 Thrust Bearing cap bolts to 41 Nm + 1/4 Turn (30 ft. lbs.+ 1/4 Turn). Remove the holding tool.
7. Install oil pan.
8. Fill engine crankcase with proper oil to correct level.