Genuine Mazda MX-5 Miata Crankshaft

Mazda MX-5 Miata Crankshaft Parts and Q&A

• Crankshaft
  LF02-11-301
  Q: How can the crankshaft be removed and installed on Mazda MX-5 Miata?

  A:

  Crankshaft may not be removed until the engine is removed out of the vehicle, and it is assumed that the flywheel, crankshaft pulley, timing belt or chain, oil pan, oil pump body, oil filter and piston/connecting rod assemblies have been removed. Measure the crankshaft endplay with a dial indicator aligned with the crankshaft, pry the crankshaft to the back, and set the dial indicator zero, pry the crankshaft to the front, and set the dial indicator zero, which should be between 0.003 and 0.010 inch (0.076 to 0.254 mm) usually. Should a dial indicator not be available feeler gauges can be used to measure clearance. Tighten the main bearing cap bolts, progressively, until they can be loosened by hand, and then remove the main bearing caps and the crankshaft may be lifted by hand, preferably with help, because of its substantial weight. To install, be sure the engine block and crankshaft are clean and examined, place the block inverted, and take away any original bearing inserts. Wipe off all bearing surfaces, and put new upper main bearing inserts in engine block, aligning oil holes. Fit lower main bearings inserts in the caps without damaging them, and take no lubrication at this point. Wipe the crankshaft and bearer surfaces and place the crankshaft. Measure the main bearing oil clearance with Plastigage which should be only a little less than the journal width and place on each journal prior to fitting the caps without interfering with the Plastigage. Install the bolts in the order as given and take them out so as to measure the crushed Plastigage to give a clearance. When the clearance is not correct, make sure that it is clean and may be necessary to use other bearing sizes. Once the Plastigage has been scrapped off, wipe the faces of the bearing inserts clean and put a thin coat of moly-base grease or engine assembly lube on before replacing the crankshaft. Clean up all the surfaces and then use the bolts and fit them finger-tight and ensure they are torqued. Test the crankshaft endplay again and turn the crankshaft to test whether it is binding and it must rotate without any difficulty. Lastly, fit the new rear main oil-seal.