Before a repair quote can be provided to the customer, an inspection of the crankshaft must be made by both a visual examination and with precision measuring instruments. Before this can occur, the crankshaft must be cleaned. Different automotive machine shops use different cleaning techniques, but baking and blasting the crankshaft is a modern process that allows more details to be seen during a visual inspection. Other cleaning processes involve the use of a degreaser machine or acid dip tank. Because of EPA requirements involving the use of hazardous chemicals are quite strict, more shops are using an automotive bake oven (pictured above) and blast process to clean crankshafts.
With a clean crankshaft, the engine machinist is able to perform an inspection that is both thorough and accurate. At this stage a micrometer is used to determine how far out of tolerance the main and rod journals are. The thrust surface is also measured with a snap gauge and micrometer to determine how much excessive endplay may be present. Providing the crankshaft journals and thrust have available undersize bearings available, or excessive damage can be repaired with a weld, the machinist will then inspect the crankshaft snout, seal surface and rear flange for damage. Continue reading