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Checking crankshaft clearances

Checking crankshaft clearances


Clean the crankshaft and use a micrometer to measure the crankpins. Measurements should be taken at several points round the circumference. Journal and crankpin out-of-round should not exceed 0.05 mm. If the measurements are close to or in excess of this, the crankshaft should be ground down to the specified undersize.

Crankpins can be ground down to the first undersize using a straight grinding wheel. If they are ground down beyond that, a grinding wheel capable of grinding radii must be used since undercutting only suffices to the first undersize. Check that the shaft is straight to within 0.10 mm, using a dial gauge. Place the shaft with crankpins No. 1 and No. 5 in V-blocks, position a dial gauge on the middle crankpin and rotate the shaft.