Gerotor Pump Cavitation Noise

[CRG]

Any thoughts or insights on the sound of cavitation for a gerotor pump? The pump in question is a lube oil pump on a marine diesel (3208NA). The sound is nothing like the typical gravel or marbles sound associated with cavitation in a centrifugal pump. There is some very minor damage on the oil pan that might have reduced the clearance between the suction screen and the bottom of the oil pan. Because the engine is located in a small boat, it is a major job to remove the 2000 lb engine assembly to have access for physical examination.

I would classify the noise as something closer to a high pitch whine, and no, it is not the sound of a turbo charger, the engine is naturally aspirated. The mystery sound is absent at low RPMs and gets louder the higher the RPM. The engine has good oil pressure. I do not know if the noise appeared after the oil pan was damaged, nor can I find this out. It is not a belt driven accessory noise. The noise is emanating from the front of the motor and does not seem to be coming from either the fuel pump or any other definitive location. The noise/whine is very loud at higher RPMs.

Would anyone that has experienced a gerotor oil pump with cativation problems, please describe the noise.

 

[tbuelna]

CRG,

A low pressure lube oil pressure pump will not make much noise if there is slight cavitation occurring. If the oil sump pick-up is being blocked enough to cause significant cavitation at the gerotor inlet port, then you would see low oil pressure.

Your engine has a gear drive off of the front end of the crank, so I'd speculate that it may be the source of your noise.

Hope that helps.
Terry