Installation

Bearing Selection
There are five crankshaft bearings, numbered one through five, from the front of the engine there is an arrow on the bearing cap that points toward the front of the engine. The center, number three bearing is the thrust bearing. The upper bearing halves have an oil groove. The lower bearing halves do not have an oil groove.

During factory assembly, the crankshaft bearings are select-fitted to each of the five crankshaft bearing bores. The proper size code is stamped on the pan rail at the corresponding crankshaft bearing bulk head. The total diameter size range of crankshaft bearing bores one through five is 79.826-79.850 mm (3.145-3.146 inch). This range divides into three sizes, represented by the numbers 1, 2 or 3 stamped on the pan rail. The crankshaft is color-marked in red/orange, blue or white, near the crankshaft bearing journal. Cross-referencing the number on the pan rail with the color on the crankshaft indicates the proper bearing selection.
- Crankshaft bearings are available in standard 0.013 mm (0.0005 inch) and 0.026 mm (0.0010 inch) undersizes for select fitting, in order to attain proper crankshaft bearing clearance.
- Undersize refers to the crankshaft diameter.
- For service purposes, bearing size combinations provide the following clearances:
- Crankshaft bearing numbers 1, 2, 3 and 4: 0.045-0.083 mm (0.0018-0.0033 inch).
- Crankshaft bearing number 5: 0.055-0.093 mm (0.0022-0.0037 inch).





NOTE: The upper crankshaft bearings must have the holes for the piston oil nozzles.





1. Install the upper crankshaft bearing inserts to the block.
2. Install the lower crankshaft bearing inserts to the crankshaft bearing caps.
3. Apply engine oil to the crankshaft bearings.

CAUTION: The crankshaft bearing caps are to be tapped into place with a brass or leather mallet before the attaching bolts are installed. Do not use the attaching bolts to pull the crankshaft bearing caps into their seats, as this may damage the bearing cap and/or block.





4. Install the crankshaft.





5. Apply a 1/8 inch bead of gasket maker, GM P/N 1052942 or equivalent, on the block, on each side of the rear crankshaft bearing cap area.
6. Apply engine-oil to the crankshaft bearing cap bolt threads.




7. Tap the Rear crankshaft bearing cap into place with a brass or leather mallet. Then Install the bolts. Tighten the bolts in the following sequence:
(1) Tighten the inner bolts to 150 Nm (110 ft. lbs.).
(2) Tighten the outer bolts to 135 Nm (100 ft. lbs.).
8. Install the main bearing cap And bearing for numbers 1, 2 and 4.
9. Apply engine oil to the crankshaft bearing cap bolt threads.
10. Tap the crankshaft bearing cap into place with a brass or leather mallet. Then Install the bolts. Tighten the bolts in the following sequence:
(1) Tighten the inner bolts to 150 Nm (110 ft. lbs.).
(2) Tighten the outer bolts to 135 Nm (100 ft. lbs.).
(3) Retighten all the bolts in the same sequence and the above torque.
11. Retighten all the bolts in the same sequence and the above torque.
12. Install the main bearing cap and the bearing for number three, the thrust bearing.
13. Apply engine oil to the crankshaft bearing cap bolt threads.
14. Tap the crankshaft bearing cap into place with a brass or leather mallet. Then Install the bolts.
15. Tighten the bolts temporarily to 14 Nm (10 ft. lbs.).
16. Measure the crankshaft end play in the following ways:
- Tap the end of the crankshaft first rearward then forward with a lead hammer. This will line up the crankshaft bearing and the crankshaft thrust surfaces.
- Tighten the center crankshaft bearing cap bolts to the same torque specifications and sequence as the other bearing crankshaft caps.
- With the crankshaft forced forward, measure at the front end of the number three crankshaft bearing with a feeler gauge. The proper clearance is 0.10-0.25 mm (0.004-0.0010 inch).
17. Inspect the crankshaft for binding.
18. Try turning the crankshaft to check for binding. If the crankshaft does not turn freely, loosen the crankshaft bearing cap bolts, one pair at a time, until the tight bearing is located.
19. Burrs on the bearing cap, foreign matter between the insert and the block or the bearing cap, or a faulty insert could cause a lack of clearance at the bearing.