Crankshaft Main Bearing Replacement

Crankshaft Main Bearing Replacement

Main Bearing Clearance Inspection

1. Remove the lower block and the bearing halves. Crankshaft and Piston Removal

2. Remove all of the old liquid gasket from the lower block mating surfaces, the bolts, and the bolt holes.

3. Clean the lower block mating surface.

4. Clean each main journal and the bearing half with a clean shop towel.

5. Place one strip of Plastigage across each main journal.

6. Reinstall the bearings and the lower block, then torque the bolts to 29 N-m (3.0 kgf-m, 22 lbf-ft) + 60 °.
NOTE:

- Do not rotate the crankshaft during inspection.

- Apply new engine oil to the bolt threads and flanges.

7. Remove the lower block and the bearings again, and measure the widest part of the Plastigage.





8. If the Plastigage measures too wide or too narrow, remove the crankshaft, and remove the upper half of the bearing. Install a new, complete bearing with the same color code(s), and recheck the clearance. Do not file, shim, or scrape the bearings or the caps to adjust clearance.

9. If the Plastigage shows the clearance is still incorrect, try the next larger or smaller bearing (the color listed above or below that one), and check clearance again. If the proper clearance cannot be obtained by using the appropriate larger or smaller bearings, replace the crankshaft and start over.






Main Bearing Selection

Crankshaft Bore Code Location

1. Numbers or letters or bars have been stamped on the end of the engine block as a code for the size of each of the five main journal bores. Write down the crank bore codes.
If you cannot read the codes because of accumulated dirt and dust, do not scrub them with a wire brush or scraper. Clean them only with solvent or detergent.






Main Journal Code Location

2. The main journal codes are stamped on the No. 1 web.






3. Use the crank bore codes and the main journal codes to select the appropriate replacement bearings from the following table.
NOTE:

- Color code is on the edge of the bearing.

- When using bearing halves of different colors, it does not matter which color is used in the top or bottom.