Essential bearing clearance is the area between the crankshaft and the principle bearings. You will need to test primary bearing clearance as a result of it could possibly have an effect on the efficiency of the engine.
If the principle bearing clearance is simply too tight, it could possibly trigger the crankshaft to bind and seize. If the principle bearing clearance is simply too free, it could possibly trigger the crankshaft to wobble and harm the bearings.