VALVE GP 8J7489 - Caterpillar

6. Remove thrust bearings (7) from the rear main bearing. 7. Install tooling (B) on crankshaft (8) as shown and fasten a hoist to it. Lift the crankshaft straight up from the cylinder block. The weight of the crankshaft for 3304 Engines is 65 kg (143 lb.). The weight of the crankshaft for 3306 Engines is 95 kg (210 lb.). 8. Use tooling (C) and remove crankshaft gear (1) from the crankshaft.
If the bearings are to be removed, put identification marks on them as to their location for installation purposes.
9. If necessary, remove the main bearings from the cylinder block and main bearing caps. If necessary, remove the connecting rod bearings from the connecting rods and connecting rod caps.Install Crankshaft
1. Put the engine in position on tooling (A). If the crankshaft journals and bores for the block and rods were measured at disassembly and found to be within specifications, no further checks are necessary. However, If the serviceman still wants to measure the bearing clearances, Plastigage is recommended. Lead wire, shim stock or use of a dial bore gauge can damage the bearing surface.The serviceman must be very careful to use Plastigage correctly. The following points must be remembered:... Make sure that the backs of the bearings and the bores are clean and dry.... Make sure that the bearing locking tabs are properly seated in their slots.... The crankshaft must be free of oil where the Plastigage touches it.... If the main bearing clearances are checked with the engine upright or on its side, the crankshaft must be supported. Use a jack under an adjacent crankshaft counterweight and hold the crankshaft against the crown of the bearing. If the crankshaft is not supported, the weight of the crankshaft will cause incorrect readings.... Put a piece of Plastigage on the crown of the bearing half that is in the cap. Do not allow the Plastigage to extend over the edge of the bearing.... Install the bearing cap using the correct torque-turn specifications. Do not use an impact wrench. Be careful not to dislodge the bearing when the cap is installed.... Do not turn the crankshaft with the Plastigage installed.... Carefully remove the cap, but do not remove the Plastigage. Measure the width of the Plastigage while it is in the bearing cap or on the crankshaft journal. Do this by using the correct scale on the package. Record the measurements.... Remove the Plastigage before reinstalling the cap.When using Plastigage, the readings can sometimes be unclear. For example, all parts of the Plastigage are not the same width. Measure the major widths to make sure that they are within the specification range. Also, experience has shown that when checking clearances tighter than 0.10 mm (.004") the readings may be low by 0.013 to 0.025 mm (.0005 to .0010"). Out-of-round journals can give faulty readings. Also, journal taper may be indicated when one end of the Plastigage is wider than the other.For complete details concerning measuring bearing clearances, see Engine Bearings