Lincoln F75Z-6303-AC Crankshaft Assembly

Remove all burrs from the crankshaft oil holes using a stone, file, or scraper to ensure the oil holes are chamfered, preventing sharp edges from gouging or scratching the new bearings. Clean the crankshaft with solvent and dry it with compressed air if available, ensuring to clean the oil holes with a stiff brush and flush them with solvent. Inspect the main and connecting rod bearing journals for uneven wear, scoring, pits, and cracks, and check the rest of the crankshaft for cracks and other damage, utilizing magnafluxing to reveal hidden issues, which can be handled by 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, taking measurements at each end of the journal near the crank throws. If the journals are damaged, tapered, out-of-round, or worn beyond specified limits, have the crankshaft reground by an automotive machine shop, ensuring the use of the correct size bearing inserts if reconditioned. Examine the oil seal journals at each end of the crankshaft for wear and damage; if grooves, nicks, or scratches are present, the new seal may leak upon reassembly. An automotive machine shop may repair the journal by pressing on a thin sleeve, but if repair isn't feasible, consider installing a new or different crankshaft.

Prior to the removal of crankshaft, to determine its endplay, slide a dial indicator with the face touching the end of the crankshaft, and parallel to it. Push the crankshaft to the back so the dial indicator reads zero, and then push it to the front to take the reading; the regular endplay measures between 0.003 and 0.010 inches or 0.076mm-0.254 mm. If the endplay varies in this range, there is no sign of wear on the thrust surfaces after removal; new main bearings may solve the problem as previously described. Thrust bearings are different for different engines and are positioned differently in the engine; positions for 4.2L V6, 4.6 L V8, 5.4 L V8, 3.5/3.7L V6, 5.0/6.2L V8. If a dial indicator is not available, the amount of clearance can be measured by feeler gauges. Turn the main bearing cap bolts slowly but steadily, to the point that they can be easily unsturted and for V8 models the loosening must be done as follows. Approximately 2005 and later models of the 4.6L V8 engine have jack screws that need to be loosened in a counter clockwise manner to remove the cap. Carefully untighten the main bearing caps and then using your hand tap the caps so that you can lift them off without dropping the bearing inserts. Slowly raise the crankshaft out and if possible, do so with help; place the main bearing cap assembly back over the engine block, while torqueing the bolt just enough to be finger tight but checking the location of the cap. For installation, make sure that component such as the engine block and the crankshaft are clean and checked. Place it in an inverted manner, take off the main bearing caps and clean the bearings of the places where the main bearing caps are placed. Replace the wear bar of each saddle with a new upper main bearing insert that has oil grooves and holes. Scrub the matt surfaces of the crankshaft and bearing insert faces and then inspect the oil way for dirt. Place the crankshaft in its rightful position and measure the main bearing oil clearance through the aid of Plastigage, which has to be slightly shorter than the width of the journals. After applying Plastigage on both journals, fit the main-bearing cap, assembly without shifting it, apply clean engine oil on the bolts, and tighten the bolts in the manner described next. Bolt in the reverse coming off, lift the caps and to make the clearance you need to measure the crushed Plastigage. If the clearance is incorrect the cause should be sought in dirt or oil interference and the bearing inserts should be replaced if necessary. The Plastigage must be removed from the journals and insert faces by washing and after that apply some thin coat of grease or assembly lube on the bearing surfaces and thrust faces. Place the crankshaft back to its position, clean the bearing insert surfaces and put a coat of oil. Ref to V6 engines, the RTV sealant should be applied to the rear main bearing cap parting line and placed the cap before four minutes. Bolt back on and tighten up, then re-measure the crankshaft end play, then turn the crankshaft over to check for any binding and insure that turning the crank with running torque of 50 in-lbs or less. Last but not the least, fit the new rear main oil seal.

On VS engines, the bolts used are what is commonly known as "torque-to-yield" bolts and cannot be used again once removed; these include the main bearing cap bolts and side bolts, but the conventional bolts such as the main cap side bolts and jack screws are reusable. Starting the assembly of the engine, the crankshaft and engine block should be clean and checked for any daamges and the position of the engine should have its bottom lacing up. You should now turn the engine until the main bearing cap is visible, and then unbolt and lift off the cap, making a point of placing the caps in an order that you will remember easily. Bearing inserts that fitted initially need to be withdrawn and the bearing surfaces ought to be cleaned. New main bearing inserts are to be fitted and oil holes in the bearings ought not to be damaged while fitting. The position of flanged thrust bearing must be correct depending on the type of the engine. Depose with witness the crankshaft and the bearing faces then put the crankshaft into its rightful position. It is recommended to check the oil clearance of the main bearing with the help of Plastigage without shifting the caps and without damaging the Plastigage. If clearance is measured with error, ensure that no obstructions were in the way at the time of measurement. Customer states after checking, wipe off Plastigage residue. For the final position of crankshaft, use oil to affected areas for the bearings, fit caps followed by tightening the bolts in the right manner. For the tightening of the V6 engines, put RTV sealant on the threaded area. On V8 engines it is important to replace the jack screws in case they were removed, the thrust washers should be greased and the main caps have to be properly fitted. Loosen new main cap bolts due to gasket removal, then apply specified torque to re-seat crankshaft. Upon that check the crankshaft end float and rotate the crankshaft and look for binding and finally fit the rear main oil seal.

The crankshaft can only be removed after the engine has been taken out of the vehicle, assuming that the flywheel or driveplate, vibration damper, timing chain(s) or gears, oil pan, oil pump, and piston/connecting rod assemblies have already been detached. Before starting the crankshaft removal, check the end play using a dial indicator aligned with the crankshaft; push the crankshaft to the rear and zero the indicator, then pry it to the front to measure the movement, which indicates end play. If a dial indicator is unavailable, feeler gauges can be used to determine clearance by prying the crankshaft forward and inserting the gauges between it and the thrust main bearing. Ensure the main bearing caps are marked for their locations; if not, number them accordingly. For V6 engines, the thrust bearing is located at the number three main bearing cap, which has upper and lower thrust bearing shells. Loosen the main bearing cap bolts/studs gradually until they can be removed by hand, noting any stud bolts for proper reinstallation. V8 engines have a more complex procedure due to the number of bolts fastening the main caps; for 4.6LREP models, remove side bolts, back off jack screws, and for 5.4L and WEP-design 4.6L engines, remove side bolts without jacking screws. Remove the main bearing cap bolts in reverse order of tightening, ensuring to pull dowel pins from the main caps on WEP 4.6L and 5.4L engines. The main bearing cap bolts are torque-to-yield and must be replaced after removal, while jack screws on REP engines are reusable. Gently tap the caps with a soft-face hammer to separate them from the block, using bolts as levers if necessary, and avoid dropping bearing inserts. Lift the crankshaft out carefully, possibly with assistance, and return the bearing inserts to their respective locations on the engine block, tightening the caps finger tight.

MAIN BEARING SOLD SEPARATE.

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