COUPLING AS-PERMANENT 3289097 - Caterpillar

Start By:a. remove oil pan 1. Turn the crankshaft until two pistons are at bottom center. Remove connecting rod caps (1) from the two connecting rods. Remove the lower half of the bearings from the caps.2. Push the connecting rods away from the crankshaft, and remove the upper half of the bearings.
Do not turn the crankshaft while any of the connecting rod caps are removed.
Install the bearings dry when the clearance checks are made. Put clean engine oil on the bearings for final assembly.3. Clean the surfaces where the bearings fit. Install the upper half of the bearing in the connecting rod. Pull the connecting rod slowly on to the crankshaft.4. Install lower half of the bearing in the cap.
When the connecting rod caps are installed, make sure that the numbers on the side of the caps are next to and respective with the number on the side of the connecting rods.
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 notallow the Plastigage to extend over the edge of the bearing.... Install the bearing cap using the correct torque-turn specifications. Do notuse an impact wrench. Be careful not to dislodge the bearing when the cap is installed.... Do notturn the crankshaft with the Plastigage installed.... Carefully remove the cap but do notremove the Plastigage. Measure the width of the Plastigage when 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 in)the readings may be low by 0.013 to 0.025 mm (.0005 to .0010 in). 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 & Crankshafts, SEBD0531.5. Check the bearing clearance with Plastigage (A). Put Plastigage (A) on the bearing.6. Put Clean Engine Oilon the threads of the rod bolts and seat surfaces of the nuts.
Do not use an