earings fail are many and varied, but they’re not usually the fault of the bearings themselves. “/>Engine bearings have the dual function of reducing friction between a rotating part of the engine (the crankshaft) and the stationary part (the main caps and engine block), as well as supporting the crank.
Because of the stresses caused by the explosions inside the internal combustion engine, the bearing material must be extremely strong, so a durable metal is required.
However, there can be literally dozens of reasons for premature wear or failure of an engine bearing. By carefully inspecting the evidence left behind, an engine builder can discover and eliminate the cause of bearing failure.
The following are some common causes of engine bearing failure:
• Dirt or Debris: Whether it’s dirt, dust, grinding remnants, shot or any other particle, debris can cause significant damage to a bearing surface.
If it’s in the lubrication system, dirt will usually leave circumferential scratches and often the offending piece will remain lodged in the bearing’s surface. Always be sure the lubrication system is flushed thoroughly before reassembling an engine.
• Insufficient Lubrication: A complete lack of lubrication in the crankcase usually leads to seizure of the bearing and total failure of the engine. But experts say a more frequent issue regarding lubrication is simply inadequate oiling. The absence of a proper oil film will result in metal-to-metal contact, occasionally to just one bearing or often to a number of them. When the bearing is damaged by oil starvation, you’ll find a very shiny surface and evidence of wiping
• Misassembly: Sometimes, failures are the result of simple installation errors. For example, if a bearing
half without an oil hole is improperly put into a
position where the hole is needed, that journal will receive no lubrication.
• Machining Issues: As with the installation issues, problems in the machining process can often result in bearing failures. An out-of-round housing bore will cause the bearing to eventually conform to the out-of-roundness. This can decrease the oil clearance enough to cause metal-to-metal contact, resulting in areas of heavy wear.
