Many diesel engine manufacturers have circulated Service Bulletins to their customers warning them of this condition and advise methods to avoid or minimise failures.
When medium speed four stroke engines have accumulated in the region of 60,000 running hours there is a condition that can develop that is sometimes described as the “cam effect” or “ridge wear”. This develops over a period of time and can be identified as a protruding band that goes around the circumference of the crankpin diameter that can lead to the failure of the crankpin bearing sometimes causing disastrous results.
The effect can cause extensive build up of heat which in turn can harden the crankpin diameter causing problems in lubrication and eventual crankpin failure. These failures can also result in broken conrods that break through the main engine crankcase doors causing considerable damage to the engine block in that area.
Expert orbital machining of crankpin diameters remove the cam effect.
Heat Treatment/annealing that can reduce the surface hardness of the crankpin diameter to allow the re-machining of the crankpin diameter for an undersize bearing.
These failures can also result in broken conrods that break through the main engine crankcase doors causing considerable damage to the engine block in that area.
Specialist cold Metalock casting repairs (metal stitching) can repair damaged engine blocks.