Nissan 12200-0W001 Crankshaft Assembly

Crankshaft removal is a process that can only happen after the engine has been removed from the vehicle and involves some prerequisites, like taking off the flywheel/driveplate, crankshaft pulley, timing belt (for 3.3L engines) or timing chain (for 2.4L and 3.5L engines), camshaft, crankshaft sprockets, oil pan, oil pump, and piston/connecting rod assemblies. In addition to this, before one embarks on crankshaft removal, it is important to examine the endplay of the crankshaft using dial indicators or feeler gauges. The dial indicator should be mounted with the stem in line with the crankshaft to contact one of its throws and zeroed out. After that, gently push back the crankshaft and observe the reading given by a dial indicator as this will indicate endplay. If there are excessive side clearances in excess of specifications then an investigation into wear on thrust surface of the crankshaft is required. If no wear is indicated then replacement of main bearing may cure end play problem. An alternative way to measure crankshaft end play uses feeler gauges to pry or push gently against the front face of the thrust bearing while placing feeler gauges between it and the front of the thrust bearing to determine how much clearance exists. Gradually loosen each main bearing cap bolt by turning it a quarter turn at a time in reverse order of tightening them until manoully removable bearing cap(s) and brace assembly are achieved.Normally cast-in arrows on main bear ing cap assembly indicate direction towards drivebelt end of engine but if these aren't there use number stamp or punch for marking cap assembly position/direction. Only mark front side of bearing cap brace when working on 3.3L engines because caps and brace are asingle unit.On 3.5L engines however, front part of bearing cap brace should be marked, removed and then inspected for installation marks on main bearing caps before they are removed from the engine. Notably, 2.4L engines do not include a main bearing cap brace. Theoretically, when loosening cap assembly from the engine block, you should be careful about losing bearing inserts in case they come out with the cap assembly. Thereafter, lift crankshaft out of the engine being cautious about its significant weight by preferably using help. Finally, put back cap assembly at its position ontheengineblockwiththebearinginsertsintactandtightenboltsfinger-tight.Incaseof3.5Lengines,the condition of main bearing cap bolts must be checked to ensure that there is no excessive stretching; if there is a difference of more than 0.0043 inch (0.11 mm) between indicated areas in bolt diameter, replace the bolts even complete sets if necessary.

If the oil seal journals are worn or damaged, an automotive machine shop may be able to repair the journal by pressing on a thin sleeve. If repair is not feasible, a new or different crankshaft should be installed.

If the journals are damaged, tapered, out-of-round, or worn beyond acceptable limits, have the crankshaft reground by an automotive machine shop, ensuring the correct size bearing inserts are used if reconditioned.

Clean the cap assembly bearing faces, install it with the arrow pointing toward the timing belt end, and tighten the bolts in three steps to the specified torque without rotating the crankshaft.

Before removing the crankshaft, check the endplay by mounting a dial indicator with the stem aligned with the crankshaft and touching one of the crank throws. Push the crankshaft to the rear and zero the dial indicator, then pry it to the front and check the reading to determine the endplay.

To prepare for the main bearing oil clearance check, place new main bearing inserts into the main bearing saddles in the block, ensuring proper alignment with the oil holes in the block. Insert the flanged thrust bearing without lubrication, depending on the engine type.