MUFFLER & CONVERTER AS 2144859 - Caterpillar

Measure the tension of the main bearings when free. If the measurements are below the limit, replace the upper and lower main bearings as a set. Never attempt to expand the bearings for reuse.(p) Roundness and Cylindricity of Crankshaft Determine roundness and cylindricity of the crankshaft based on measurements of journal and pin O.D.s. If the limit is exceeded, grind to undersize.(q) Crankshaft Bend If the limit is exceeded, replace. Read the crankshaft center journal runout with a dial indicator. One half of the reading is the bend.(r) Correction of Crankshaft to Undersize If a journal or pin is damaged or seized, grind the crankshaft by using the following procedures.Replace the bearing with an undersize.* During grinding, use care not to change the center distance of journal and pin.* Use care also not to change the width of journal and pin.* Finish the fillet smooth to the specified radius.* Check for grinding cracks by the magnetic particle inspection method. Make also sure that the surface hardness (Shore hardness Hs 75 or more) has not decreased. * When grinding the crankshaft with a grinder, the grinder and crankshaft must be turned counterclockwise as viewed from the crankshaft front end.* To finish the crankshaft with a grindstone or sandpaper, turn the crankshaft clockwise.Crankshaft undersize dimensions (3) Reassembly (a) Installation of Upper Main Bearing and Thrust Plate Install the thrust plate and upper main bearing to the crankcase. 1. Install the thrust plate with its side having no oil groove toward the crankcase.2. Line up the lug of main bearing with the lug groove in crankcase. Note that the upper main bearing has an oil hole, which must not be confused with the lower.3. Apply engine oil to all sliding surfaces.(b) Installation of Crankshaft Gear When the crankshaft gear was removed, it must be heated with a piston heater or similar device before being reinstalled onto the crankshaft.(c) Installation of Main Bearing Cap Fit the lower main bearing into the main bearing cap. At the time, make sure that the main bearing lug is aligned with the main bearing cap lug groove. Install also the thrust plate onto the main bearing cap in the rear-end position.Make sure that the main bearing cap lug groove and crankcase lug groove are on the same side. Ensure also that the embossed numbers on main bearing caps are in ascending order from the front of engine. 1. Face the side of thrust plate having no oil groove toward the main bearing cap.2. Use thrust plates of the same size for the crankcase and main bearing cap rear end.3. Apply