Checking crankshaft clearances

/ 9-3 (9400) / 1998 / 2. Engine / Basic engine, 4-cylinder petrol / Adjustment/replacement / Checking crankshaft clearances

Clean the crankshaft and measure the journals with a micrometer. Measurements should be taken at several points round the circumference. Main journal and crank pin out-of-round should not exceed 0.005 mm. If the measurements are close to or in excess of this limit, the crankshaft should be ground down to the specified undersize.

Crankpins can be ground down to the first undersize with 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 with a dial gauge. Place the shaft with crankpins 1 and 5 in V-blocks. Apply the dial gauge to the middle pin and rotate the shaft.

Checking crankshaft clearances

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