GM 90537273 Engine Crankshaft

Crankshaft removal is possible only if the engine has been removed from the car, but again, this is possible if such components as the flywheel, crankshaft pulley, timing belt or chain, oil pan, oil pump body, oil filter, and piston/connecting rod assemblies have been previously removed. Crank pin end float will be checked before the withdrawal of the shaft and by placing a dial gauge on the crankshaft, measure the degree of crank pin towards the front side. Loosen the crankshaft towards the rear and set the indicator zero on the dowel pin, and then tighten the crankshaft towards the front side to check the 'Out' reading, which should vary as follows 0.003 to 0.010 inch (0.076 to 0.254mm). In the event that the dial indicator cannot be used, then clearance maybe determined using feeler gauges. Do the same to all the lower crankcase or main bearing bolts but do it gradually until it is possible to take them out by use of hands For the next time, replace them with new ones. Take off the lower crankcase or the main bearing bridge; ensure that the bearing inserts do not fall. In the case of V6 engines, it will be important to be very keen with the orientation of the main bearing caps. Slowly raise out the Crankshaft, if possible with help, and replace the caps and Bridge or lower Crankcase Finger Tight and make sure to keep everything in order. For installation, make it a point that the engine block and crankshaft are free from dirt and has been checked. Take off the lower crankcase or bearing bridge and main bearing caps with nut and bolt based on the model and cleans the bearing surfaces well. Place new upper main bearing inserts in the engine block so that oil holes are in the proper orientation and fit lower inserts in place. To do this check main bearing oil clearance employing plastigage and compare the result with standard range. If clearance is incorrect always check for cleanliness of the rolling element and if need be think about using a different size of the bearing. Finally, all the plastic gage are cleaned and then the crank shaft journals and thrust faces should be lubricated with grease or assembly lube before laying the crank shaft back in place. Scrub the insert faces and the surfaces of the lower crankcase or bearing caps, and then install them, RTV sealant being applied to the rear main bearing cap grooves for V6 models. Loosen all bolts and then tighten them to the recommended torque in the right sequence, and also, the crankshaft bearing bridge sleeves must be adjusted correctly. Lastly, apply sealant into the.RMBB and install the lower crankcase perimeters bolts and finally check the end play of the crankshaft. The crankshaft must be rotated to see if there is binding with the bearings whereby it must rotate freely with running torque of 50 in-lbs or less is acceptable, before fitting of the new rear main oil seal can be done.

Crankshaft removal is possible only if the engine has been removed from the car, but again, this is possible if such components as the flywheel, crankshaft pulley, timing belt or chain, oil pan, oil pump body, oil filter, and piston/connecting rod assemblies have been previously removed. Crank pin end float will be checked before the withdrawal of the shaft and by placing a dial gauge on the crankshaft, measure the degree of crank pin towards the front side. Loosen the crankshaft towards the rear and set the indicator zero on the dowel pin, and then tighten the crankshaft towards the front side to check the 'Out' reading, which should vary as follows 0.003 to 0.010 inch (0.076 to 0.254mm). In the event that the dial indicator cannot be used, then clearance maybe determined using feeler gauges. Do the same to all the lower crankcase or main bearing bolts but do it gradually until it is possible to take them out by use of hands For the next time, replace them with new ones. Take off the lower crankcase or the main bearing bridge; ensure that the bearing inserts do not fall. In the case of V6 engines, it will be important to be very keen with the orientation of the main bearing caps. Slowly raise out the Crankshaft, if possible with help, and replace the caps and Bridge or lower Crankcase Finger Tight and make sure to keep everything in order. For installation, make it a point that the engine block and crankshaft are free from dirt and has been checked. Take off the lower crankcase or bearing bridge and main bearing caps with nut and bolt based on the model and cleans the bearing surfaces well. Place new upper main bearing inserts in the engine block so that oil holes are in the proper orientation and fit lower inserts in place. To do this check main bearing oil clearance employing plastigage and compare the result with standard range. If clearance is incorrect always check for cleanliness of the rolling element and if need be think about using a different size of the bearing. Finally, all the plastic gage are cleaned and then the crank shaft journals and thrust faces should be lubricated with grease or assembly lube before laying the crank shaft back in place. Scrub the insert faces and the surfaces of the lower crankcase or bearing caps, and then install them, RTV sealant being applied to the rear main bearing cap grooves for V6 models. Loosen all bolts and then tighten them to the recommended torque in the right sequence, and also, the crankshaft bearing bridge sleeves must be adjusted correctly. Lastly, apply sealant into the.RMBB and install the lower crankcase perimeters bolts and finally check the end play of the crankshaft. The crankshaft must be rotated to see if there is binding with the bearings whereby it must rotate freely with running torque of 50 in-lbs or less is acceptable, before fitting of the new rear main oil seal can be done.

Indeed, the crankshaft is one of the few components that can only be accessed when the engine is removed from the car, provided that such WI bits as the driveplate, crankshaft pulley, timing belt or chain, oil pan, oil pump body, oil filter and piston/connecting rod assemblies are already removed. Before removal, and with the crankshaft suitably aligned, use a dial-gauge to take a reading of the amount of crankshaft endfloat. Place the indictor blade on the counter surface, pry the crankshaft to the rear and rotate the indicator zero, then pry the crankshaft to the front and observe the dial which should show a total indicator movement of .003 in. to .010 in. (0.076mm-0.254mm). In a situation where a dial indicator is not available, clearance can be measured with the aid of feeler gauges. Take out half of the main bearing bolts to independently pedals that can be rotated, then gently drill the main bearing caps or bridge on the bulkhead with a soft-steel hammer and lift it up. Remove the crankshaft as delicately as possible, because of its weight which should be manageable by two people, then reinsert the main bearing caps with the arrow facing forward. Installation requirements include that the engine block, crankshaft should be clean and checked. At this stage, position the engine block upside down and you have to remove the main bearing caps and clean the bearing surfaces. The new upper main bearing inserts should be installed in the block, and lower inserts on to the caps in the right manner. Scrub the crankshaft and make certain the oil holes are clear of dirt. Place the crankshaft on the main bearings and perform a Plastigage measurement of the main bearing oil clearance should be within the set limit. If the clearance is incorrect the observer should check that no debris was present at the time of the measurement and should consider changing the bearing inserts if needed. When the Plastigage is removed, coat the bearing surfaces and the crankshaft journals with a layer of grease or assembly lube then place the main bearing caps and make sure that the arrow faces the front. After tightening the bolts, ensure that they are tightened in the correct order and for some of the engine types, turn the sleeves then apply sealant if required. Last but not the least, verify the crankshaft end play and make it free to rotate with little or no drag by sorting it out before fitting of a new rear main oil seal.

The engine block and crankshaft must be cleaned and inspected.

The engine must be removed from the vehicle.

The crankshaft is carefully lifted out of the engine with the help of an assistant.