TAPE 4740149 - Caterpillar

START BY:a. remove oil pump 1. Check each main bearing cap (2) for its location on the engine. Each cap has an arrow (1) which shows the direction of the front of the block and a number (3) which gives the location of that cap.2. Remove No. 2 through No. 6 main bearing caps from the engine. Remove the lower bearings from the caps.3. Remove the thrust plate from each side of the No. 4 upper main bearing.
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.
4. Turn the crankshaft until tool (A) can be installed in oil hole (4). Turn the crankshaft in the direction which will push the upper main bearing out, tab end first. Install the main bearings dry when clearance checks are made. Put clean engine oil on the main bearings for final assembly. 5. Install the lower bearings in the bearing caps.6. Install the upper bearings in the cylinder block with tool (A). Be sure tab (5) on the back of the bearings fits in the groove of the caps and cylinder block. When the bearing clearance is checked and the engine is in a vertical position such as in the vehicle, the crankshaft will have to be lifted up and held against the upper halves of the main bearings to get a correct measurement with Plastigage (B). The Plastigage will not hold the weight of the crankshaft and give a correct indication. If the engine is in a horizontal position, such as on an engine stand, it is not necessary to hold the crankshaft up. Do not turn the crankshaft when the Plastigage is in position to check clearance.7. Check the bearing clearance with Plastigage (B) as follows:
When Plastigage is used to check bearing clearances, do not use an impact wrench for the torque tightening sequence. However, an impact wrench can be used for the final tightening torque.
a. Put clean oil on the threads of the cap bolts. Install the caps and cap bolts, finger tight.b. Tighten the bolts on the tab end of the caps first to a torque of 258 14 N m (190 10 lb.ft.).c. Tighten the bolts on the other end of the caps to a torque of 258 14 N m (190 10 lb.ft.).d. Put a mark across the bolt head and cap. Tighten the bolts opposite the tab end 120° 5° more. Tighten the bolts on the tab end of the cap 120° 5° more. Make sure the main bearing caps are installed with their identification number (7) in alignment with the identification number on the side of the cylinder block and arrow (6) toward the front of the block.8. Remove the main bearing caps and tool (B).9. Measure the thickness of the Plastigage to find the bearing clearance. The clearance for new bearings must be