3208 MARINE ENGINE Caterpillar


Crankshaft Main Bearings

Usage:

Remove & Install Crankshaft Main Bearings

Start By:

a. remove oil pan

1. Check each main bearing cap for its location on the engine. Each cap has a number which gives the location of that cap. Make a note that the number on each cap is toward the front of the cylinder block.

2. Remove the bolts and washers that hold main bearing cap (2) in place. Remove the bearing cap and the lower half of the main bearing. Use Tool (B) to remove the bolts that hold the No. 1 main bearing cap in position.

3. Remove bearing (1) from the bearing cap.


NOTICE

If the crankshaft is turned in the wrong direction, the tab of the bearing will be pushed between the crankshaft and the cylinder block. This will cause damage to the crankshaft and block.


NOTE: The No. 1 main bearing journal has no oil hole. To remove this bearing, put a thin piece of soft material, that will not damage the crankshaft journal, against the end of the bearing opposite the tab. Hit the bearing with the soft material until the tab of the bearing is free from the groove in the block.

4. Turn the crankshaft until Tool (A) can be installed in the oil hole in the crankshaft journal. Install Tool (A). Turn the crankshaft in the direction which will push the upper main bearing out, tab end first.

NOTE: The following steps are for installation of the crankshaft main bearings.

NOTE: Put clean engine oil on the bearings for final assembly.

5. Install the lower bearing in the bearing caps. Install upper bearings (bearing with the oil hole) in the cylinder block with Tool (A).


NOTICE

When bearing caps are installed, make sure the number on the side of the cap is next to and respective with the number on the engine block.


6. Put 4C-5593 Thread Lubricanton the bolt threads and washer faces. Put clean engine oil on the lower half of the main bearing. Put the bearing cap and lower half of the main bearing in position on the engine. Install the bolts. Tighten bolt (5) to a torque of 40 ± 4 N·m (30 ± 3 lb ft). Tighten bolt (4) to a torque of 40 ± 4 N·m (30 ± 3 lb ft). Put a mark on both heads and the cap. Tighten bolt (4) 120 ± 5 degreesmore. Tighten bolt (5) 120 ± 5 degreesmore.

7. Do Steps 1 through 6 for the remainder of the bearings.

8. Check the crankshaft end play with Tooling (C). The end play is controlled by the thrust bearing on No. 4 main bearing. The end play with new bearings must be 0.08 to 0.25 mm (.003 to .010 in). The maximum permissible end play with used bearings is 0.36 mm (.014 in).

NOTE: For more detailed information regarding the crankshaft main bearings, see the topic "Bearings For Connecting Rods And Mains" in the Specifications Manual.

End By:

a. install oil pan

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