HEAD 1250026 - Caterpillar

Remove Crankshaft (3306)
start by:a) remove flywheel housingb) remove timing gear coverc) remove pistons1. Turn the crankshaft until the timing mark on the crankshaft gear (1) is in alignment with the timing mark on camshaft gear (2).2. Make a mark on the teeth of the magneto drive gear and the idler gear in their engaged position at location (A). Put a mark of identification on the engaged teeth of idler gear and camshaft gear at location (B). This will give assistance in the correct timing of the camshaft for the magneto drive during crankshaft installation.3. Fasten a hoist to the crankshaft.4. Remove the caps for the main bearings.5. Remove the crankshaft. Weight of the crankshaft is 210 lb. (95 kg).6. Remove the crankshaft main bearings from the cylinder block and from the caps.Install Crankshaft (3306)
1. Clean the surfaces on the cylinder block for the bearings. Install the upper halves of the main bearings in the block.2. Put the crankshaft in the block with a hoist. Be sure all timing marks are in alignment.3. Clean the main bearing caps. Install the lower halves of the main bearings in the caps.4. Check the main bearing clearance with Plastigage (A). Install the caps in their correct places. Be sure the number on the cap is toward the number on the pan surface on the left side of the block. 5. Put clean oil on the threads of the bolts and on the faces of the washers that hold the main bearing caps. Install the bolts and washers. Tighten both bolts to 30 3 lb.ft. (40 4 N m). Put a mark on the bolt heads and bearing caps. Tighten the bolts 90° from the mark as shown. Remove bearing caps and measure the thickness of the Plastigage (A). Main bearing clearance (Plastigage thickness) must be .0030 to .0065 in. (0.076 to 0.165 mm). Maximum permissible clearance is .010 in. (0.25 mm).6. Put clean oil on the upper and lower halves of main bearings. Install the caps in their correct places. Install the bolts and washers. Tighten to 30 3 lb.ft. (40 4 N m). Put marks on bolt heads and caps. Tighten each bolt 90° from the mark.7. Check the crankshaft end clearance with tool group (B). End clearance is controlled by the thrust bearing (1) on the rear main. When the bearings are installed the tab will fit into the machined area in the cylinder block. End clearance must be .0025 to .0145 in. (0.064 to 0.368 mm). Maximum permissible end clearance is .025 in. (0.64 mm).8. If the accessory drive gear, idler gear, camshaft gear or crankshaft gear has been removed or a replacement has been made, it is necessary to put the accessory drive shaft into correct timing after the engine is assembled. See TIMING MAGNETO TO ENGINE in TESTING AND ADJUSTING. end by:a) install pistonsb) install timing gear coverc) install flywheel housing