How do you measure the clearance between the crankshaft journal and bearing?

To measure the clearance between the crankshaft journal and bearing, you can use a dial gauge or feeler gauge. First, ensure the engine is assembled properly, then place the dial gauge against the journal and rotate the crankshaft to check for any movement. For a more precise measurement, insert a feeler gauge between the journal and bearing. The thickness of the feeler gauge that fits snugly without resistance indicates the clearance.