What is crankshaft runout, and how is it measured to ensure the crankshaft is not bent?

1. It is the wobble of the crankshaft axis, measured using a dial indicator while rotating the crankshaft on precision V-blocks.
2. It is the axial movement of the crankshaft, measured with a feeler gauge inside the crankcase.
3. It is the speed variance of the crankshaft, measured with a digital tachometer.
4. It is the wear of the main bearings, measured using plastic gauging thread.