Saturn 12661875 Crankshaft

To begin the process of removing the crankshaft, you measure endplay using a dial indicator or feeler gauges. Then remove the main bearing caps and finally the crankshaft itself. The engine block and crankshaft must be cleaned and inspected before installation. After removal of old main bearing caps and inserts, new ones are put in their place. Plastigage is used to check the main bearing oil clearance, and in some cases different bearing inserts may be necessary. When clearance is correct, Plastigage is removed and the crankshaft lifted out of the block of cylinders. The surfaces on which bearings are placed are oiled again for lubrication as it should be done before putting back the shaft into position. After that, tighten up your main bearing caps in sequence while checking your endplay one more time. And finally install rear main oil seal.

The crankshaft can only be removed after the engine has been pulled out of the car on the condition that such parts as the flywheel crankshaft pulley, timing chain cover, oil pan, oil pump body, oil filter, and piston/connecting rod assemblies have been stripped off. Before withdrawal make sure of the crankshaft end float by putting the dial gauge parallel to the crankshaft. Push the crankshaft to the right and then to the rear to bring the indicator to zero then push the crankshaft to the left then note down the reading which should be within the range of 0.003-0.010 inch (0.076-0.254mm). Sometimes get of clearance can be approximated if dial-indicator is not available by use of feeler gauges. Unbolt the main bearing bridge and then free up and remove the main bearing cap bolts to the point where you can do so without dropping the bearing inserts. It is recommended that you lift the crankshaft out and seeing as they are quite heavy you might have a friend help you. For installation, make sure that the engine block and the crankshaft are clean and likewise check for any signs of damages. Raise the engine block in an inverted fashion, provide no support for the crank and remove any residual support and clean up the bearing surfaces. New upper and lower main bearing inserts have to be fitted, beforehand making sure that the oil holes are in place and aligned; no lubricant shall be applied at this time. Using Plastigage to check the oil clearance and make certain that the Plastigage is installed correctly and the bolts are tighten correctly and compare the width of the crushed Plastigage as shown on the scale. If clearance is not as specified, check the fact that no debris was in evidence when the clearance was measured, and consider machining or replacing the bearing inserts in this case. If you found some Plastigage on the crankshaft, then remove it, and apply some grease or assembly lube to the bearing surfaces and lay the crankshaft back in its position. The main bearing caps should be fitted correctly and oil put on the bolts before tightening as provided for. Lastly, once more adjust the crankshaft end-float and double check it for any drag on it before fitting a new rear main oil seal.

The crankshaft is loose and can only be removed after removing the engine from the car, provided other parts which include the flywheel, crankshaft pulley, timing chain, oil pan, oil pump body, oil filter, piston/connecting rod assembly have been removed. Prior to the removal, use a dial to set a dial indicator parallel to the crankshaft in order to measure the crankshaft endplay. Move the crankshaft to the rear of the cylinder and note down the reading on the indicator; move the crankshaft to the front and take another reading; the amount of movement should range from 0.003 to 0.010 inch (0.076 to 0.254 mm). If you do not have access to dial indicator, then clearance can be measured by the use of feeler gauges. Loosen the main bearing cap bolts progressively, after that, take off the main bearing caps paying attention not to drop the bearing inserts. It is very heavy; better to lift it out gingerly or better still with some help because of the weight. It is recommended for installation that the engine block and crankshaft should be cleaned and checked. Place the engine block on its head, remove any crossbars or caps from the above and scrub the bearing area. New upper main bearing inserts are to be installed without being confused with each other and are required to be clean. Examine the oil holes on the crankshaft; thereafter, position the crankshaft into its proper place. When the bearing is not fitted permanently, inspect the clearance of the main bearing by using Plastigage and it should be slightly smaller than the width of the journal. Position only the Plastigage on each journal and then fit the caps without moving the Plastigage then torque the bolts on turn wise manner. You should then read the width of the crushed Plastigage against the scale in order to get the clearance. If the clearance is incorrect there may be dirt or oil interference and if so there may be a range of different bearing inserts to consider. Remove any Plastigage left on the journals and insert faces and lubricate bearing surface and thrust faces with a thin film of grease or assembly lube. Place the crankshaft back onto the engine clean the concluded faces of the bearing insert, and install the main bearing caps properly. Coat a thread of the bolt with the clean engine oil, tighten the bolt loosely and then tighten them strictly following the right pattern. Again check the crankshaft end play and turn the crankshaft making sure it moves freely and with a running torque of 50 in lbs or less. Last but not the least install a new rear main oil seal.

To begin the process of removing the crankshaft, you measure endplay using a dial indicator or feeler gauges. Then remove the main bearing caps and finally the crankshaft itself. The engine block and crankshaft must be cleaned and inspected before installation. After removal of old main bearing caps and inserts, new ones are put in their place. Plastigage is used to check the main bearing oil clearance, and in some cases different bearing inserts may be necessary. When clearance is correct, Plastigage is removed and the crankshaft lifted out of the block of cylinders. The surfaces on which bearings are placed are oiled again for lubrication as it should be done before putting back the shaft into position. After that, tighten up your main bearing caps in sequence while checking your endplay one more time. And finally install rear main oil seal.

During installation, the engine block and crankshaft must be cleaned and inspected.

JUST THE CRANKSHAFT