Crankshaft Damage

Crankshaft Damage Points : crankshaft damage, rod bearing knock, main bearing knock, excess crankshaft endplay Crankshaft problems include journal wear main bearing wear, connecting rod bearing wear and resulting low oil pressure. Rod Bearing Knock Connecting Rod bearing knock is caused by wear and excessive rod Bearing-to-CrankShaft clearance. It will produce a light regular rapping noise with the engine floating (point at which throttle is held constant and engine is not accelerating). It is loudest after engine warm up. In a cold engine, thickened oil tends to Cashion and quiet rod knock.

To locate a bad rod hearing, short out or disconnected each spark plug wire one at a time. The loose, knocking rod bearing may quit down or change pitch when its spark plug is disconnected. Main Bearing Knock Main bearing knock is similar to connecting rod bearing knock but is slightly deeper or duller in pitch. It is usually more pronounced when the engine is more pronounced when the engine is pulling or lugging under a load: Bearing and possibly journal wear are letting the crankshaft move up and down inside the cylinder block.

Main bearing wear will usually reduce oil pressure. Remove the oil pan and pressure test the lubrication system. Extensive oil flow out of one or more of the main bearings implies too much hearing clearance. If a pressure tester is not available remove and inspect each of the main bearing. If the crankshaft is not worn bearing insert replacement should correct the problem. Excess Crankshaft Endplay Excess crankshaft endplay is caused by a worn main thrust bearing. Thrust bearing wear can produce a deep knock, usually when applying and releasing the clutch (manual transmission). With an automatic transmission, the endplay problem may only show up as a single thud or knock upon acceleration or deceleration.