Mopar 5184251AH Crankshaft

To remove the crankshaft, one has to tow the engine out of the car and assuming that the following components have been removed; driveplate, crankshaft pulley, timing belt or chain, oil pan, oil pump body, oil filter, oil pump pick-up tube, windage tray and connecting rod/bosses. Before removing measure the crankshaft end play by placing the dial indicator on the crankshaft as shown below. Rotate the crankshaft to the rear and set the indicator to zero then turn it to the front to read the figure, depending on the engine type it should read between 0.003 to 0.010 inch (0.076 to 0.254 mm). In case, one has no dial indicator, feeler gauges can be applied to decent clearance measurement. On 2.4L engines, you will have to remove the bolts holding the ladder frame and detach this from the engine block. It is necessary to use new cap bolts to assemble the engine and the old bolts must be used for shaft oil clearance measurement. Gradually, relieve the primary bearing cap bolts and using a soft-faced hammer tap the cap lightly and then remove the cap gently. Take out the crankshaft if possible, with help, and replace the bedplate/main bearing caps with the arrow pointing forward. It is recommended that during installation the engine block and the crankshaft must be cleaned well and inspected too. The new target wheel has to be installed on 2.4L and on 3.6L engines, using a new bolt which must be tightened in turn. The engine block has to be positioned upside down, the main bearing caps have to be removed and the bearing surfaces have to be cleaned. Set new upper main bearing inserts and make sure the oil holes are in line; fit Thrust washers in the proper journals. Remove the old piston assembly; clean the crankshaft and put it horizontally; check the main bearings oil clearance with the help of Plastigage. Place main bearing caps without removing from the Plastigage and provide proper alignment and torque settings. If the clearance turns out to be marginal with respect to the specified limits it is recommended to investigate whether the bearing is restricted by dirt or oil and decide about replacement of bearing inserts. All Plastigage should be cleaned off just prior to final assembly, and the bearing surfaces and thrust faces should be coated lightly with oil. Reinstallation of crankshaft should be done; the bearing insert faces should be cleaned and treated with oil before fixture of the main bearing caps. After that, with the bolts tightened progressively in horn sequence, check crankshaft end-play again. Revolve the Crank Shaft with your hands and feel whether the Crank Shaft is binding anywhere in its operation. For 2.4L engines use RTV sealant on the engine block base prior to positioning of the ladder frame and doing the tightening of the bolts. Last of all, it is necessary to fit the new rear main oil seal assembly and the oil pump or the pick-up tube.

Remove all burrs from the crankshaft oil holes with a stone, file, or scraper to ensure sharp edges don't gouge or scratch the new bearings. Clean the crankshaft with solvent and dry it with compressed air if available. Check the main and connecting rod bearing journals for uneven wear, scoring, pits, and cracks. Rub a penny across each journal several times; if copper rubs off and embeds in the crankshaft, the journals should be reground, indicating roughness. Inspect the rest of the crankshaft for cracks and other damage, and have it magnafluxed to reveal hidden cracks at an automotive machine shop. Measure the diameter of the main and connecting rod journals with a micrometer, comparing results at several points to detect taper and out-of-round conditions. If the journals are damaged, tapered, out-of-round, or worn beyond limits, have the crankshaft reground by an automotive machine shop, ensuring the correct size bearing inserts are used if reconditioned. Check the oil seal journals at each end of the crankshaft for wear and damage; if grooves, nicks, or scratches are present, new seals may leak upon reassembly. An automotive machine shop may repair the journal by pressing on a thin sleeve, but if repair isn't feasible, a new or different crankshaft should be installed. Finally, examine the main and rod bearing inserts.

Before removing the crankshaft, measure the endplay by mounting a dial indicator aligned with the crankshaft and touching its end. Pry the crankshaft to the rear and zero the dial indicator, then pry it to the front and check the reading; the distance traveled indicates the endplay, which typically ranges from 0.003 to 0.010 inches (0.076 to 0.254 mm). If the endplay exceeds this range, inspect the crankshaft thrust surfaces for wear after removal, and if no wear is found, new main bearings should resolve the issue. If a dial indicator is unavailable, use feeler gauges by prying the crankshaft to the front and slipping the gauges between the crankshaft and the thrust bearing or washer to measure clearance. For 3.6L V6 engines, remove the windage tray bolts in reverse order of installation. For 2.5L four-cylinder and six-cylinder engines, check if the main bearing caps are marked for their locations, numbering them consecutively from front to rear if necessary, and ensure the cast-in arrow on the main cap points to the front. For 2.4L four-cylinder engines, loosen the main bearing cap/bed plate fasteners gradually until they can be removed by hand, taking care not to drop the bearing inserts. For 3.6L V6 engines, remove the windage tray bolts, main cap bolts, and cross-bolts, purchasing new bolts for reassembly, and tap the caps with a soft-face hammer to separate them from the block, using bolts as levers if needed. For 2007 and later 3.8L V6 engines, remove the main cap cross-bolts and purchase new ones for reassembly, while for all other engines, follow the same procedure as previously described. Finally, carefully lift the crankshaft out of the engine, ideally with assistance due to its weight, and with the bearing inserts in place, reinstall the main bearing caps/bed plate onto the engine block, tightening the fasteners finger-tight.

Crankshaft assembly is the first process in the assembling of an engine assuming the block and crank shaft are first cleaned, inspected and repaired. Align the underside of the engine block, then take off the main bearing cap screws and the caps, stack them in an order before lifting the caps off. If present, then remove the original bearing inserts from the block and caps, but make sure the bearing surfaces are clean to the extent that they will give the correct oil clearance. New upper main bearing inserts should be cleaned on their back side and each of the main bearing saddles should have an insert in the correct position regarding to oil grooves and holes. For specified saddles setting the thrust bearing in specified engine types. Clean the bearing insert faces and crankshaft journals and the crankshaft in place should now lie. The main bearing oil clearance must be checked using Plastigage and must not be below or above standard range. If the clearance is not acceptable then check for cleanliness of the bearing insert and if required go other types of bearing inserts. After cleaning with solvent all Plastigage residue should be wiped off and in its place, a thin layer of grease or assembly lube should be applied where there is to be an interface between the journals and bearing for crankshaft also while tightening the seals a special sealant should be used where necessary. Torque the main bearing cap bolts in the sequence and to the specified torque, inspect crankshaft end-play and binding. For different sorts of the engines, there are certain procedures, which include the checks of the tightness of installations and the proper operation of the parts in the assembled device as tight schedules. Last, fit the new rear main oil seal and other parts, if required as shown in the standard service bulletin.

The elimination of the crankshaft requires that the engine be pulled out on the vehicle. Before taking the crankshaft away, it is measured using a dial indicator or feeler gauges to find out about endplay. Therefore, one should gently tap assembly with a soft-face hammer to release it from cylinder block as well as loosen main bearing cap/bedplate bolts. At this stage, another person assists in lifting crankshaft from engine very carefully. During installation, this engine block is placed bottom side up and main bearing cap assembly is removed. In addition, original bearing inserts are taken out and surfaces cleaned. Further still, new upper main bearing inserts are put in all main bearing saddles ensuring oil holes are properly lined up inside them; thrust washers are situated in right journal while lower main bearing inserts fitted into main bearing cap. Then clean faces of blocks with the journal rings and crankpin journals for bearings installations. Afterward, lay crankshaft into its position within cylinder block and verify clearance between it and other parts by using Plastigage method. The following step is putting the main bearing cap assembly onto both crankshaft's one end and cylinder block then fastening nuts appropriately. Now, remove plastigauge and scrape off any burs from contact surface of bearings If necessary lift out piston shaft from inside cylinder through these square windows which enables positioning thin film lubricating fluid on each one of bearings against rotating shaft in its place again similar manner as previously mentioned above before having returned said part back into said surrounding machined aperture there being also supplied with subsequent removal lubricated afterwards cleaning annealed metal surfaces by means again given next words since therefore towards after before although yet because so if otherwise however except along beside etc.; The main bearing cap or bedplate is installed onto the crankshaft and cylinder block, and the bolts are tightened to the specified torque. Re-measure crankshaft endplay and turn it over by hand to ensure that it moves freely. Finally, insert the rear main oil seal.