Main Bearings Failure Analysis
A. Bearing failures caused by lack of proper lubrication
Notice the extremely polished condition of the bearings with the worst streaking toward the center of the bearing. This is an indicator of oil starvation, possibly from a dry start up or low oil.
B. Bearing failures caused by lack of proper lubrication
The following picture shows all of the main bearings laid out in the order they were removed. Red arrows point to bearings experiencing catastrophic failure. The blue arrow shows number seven bearing set starting to failure. Note all the bearing show shiny rub spots that are a further indication of lack of lubrication.
C. Examples of bearing failures
The picture shows a wear pattern caused by an uneven and rough cam bearing bore in block.
Foreign material trapped between main bearing and block.
Example of uneven wear caused by bore distortion
Example of uneven wear caused by a bent connecting rod
Example of uneven wear caused by severely worn crankshaft rod journals
Example of a bearing failure caused by assembly error; the oil feed hole in the connecting rod was not lined up with the bear lubrication hole.
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