Nissan 12200-7Y00A Crankshaft Assembly

The crankshaft can only be removed after the engine has been taken out of the vehicle, assuming that the flywheel/driveplate, crankshaft pulley, timing belt for SOHC engines, timing chain for DOHC engines, sprockets, oil pan, oil pump, and piston/connecting rod assemblies have been detached. Before removing the crankshaft, check the endplay by mounting a dial indicator 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. If it exceeds the specified limit, inspect the crankshaft thrust surfaces for wear; if no wear is found, new main bearings may resolve the issue. If a dial indicator is unavailable, feeler gauges can be used by prying or pushing the crankshaft forward and measuring the clearance between it and the rear main bearing. Loosen the main bearing cap bolts gradually until the cap and brace assembly can be removed by hand, ensuring to follow the reverse of the tightening sequence. Gently tap the cap assembly with a soft-face hammer to separate it from the engine block, using the bolts as levers if necessary, and take care not to drop the bearing inserts. Carefully lift the crankshaft out, possibly with assistance due to its weight, and return the cap assembly to its position on the engine block, tightening the bolts finger tight. For 2002 or later models, unbolt the oil jets from the cylinder block. On DOHC engines, check the main bearing cap bolts for excessive stretching; if there is a difference of 0.0043 inch (0.11 mm) or more in diameter between indicated areas, the bolts should be replaced, often making it more economical to buy a complete set rather than individual bolts.

Remove all burrs from the crankshaft oil holes using a stone, file, or scraper. 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. Check the main and connecting rod bearing journals for uneven wear, scoring, pits, and cracks, and inspect the rest of the crankshaft for cracks and other damage, which should be magnafluxed to reveal hidden issues, typically handled by an automotive machine shop. Measure the diameter of the main and connecting rod journals with a micrometer, comparing the results to the specified standards, and measure at various points around each journal's circumference to determine if it is out-of-round, as well as at each end of the journal near the crank throws to check for tapering. If the journals are damaged, tapered, out-of-round, or worn beyond limits, have the crankshaft reground by an automotive machine shop, ensuring the use of the correct size bearing inserts if reconditioned. Check the oil seal journals at each end of the crankshaft for wear and damage; if a groove has formed or if there are nicks or scratches, 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. Finally, examine the main and rod bearing inserts.

They probably used a different manufacturer so they altered the p/n to reflect that.