Fuel-lubed vs. Oil-lubed Injection Pumps

Fuel-lubed vs. Oil-lubed Injection Pumps

06-06-2005, 12:49 AM

#1 (permalink)

rbattelle

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Join Date: Nov 2001 Location: Dayton, OH Posts: 9,522 Old Reader's Rigs Gallery

Fuel-lubed vs. Oil-lubed Injection Pumps

It is my understanding that the P7100 is lubricated primarily by engine oil. The VP-44 and CP-3 are both fuel lubricated only. It seems like the P7100 is significantly less prone to failure as a result of a failed low pressure fuel system.

So my question is - why did Cummins change from an oil lubricated pump to a fuel lubricated pump? I suppose "technically" it's somewhat simpler internally to just use the fluid you're pumping to provide lubrication.

But an oil-lubricated injection pump sure seems like it would cut down on all the VP-44 (and CP-3) failures from bad lift pumps.

Perhaps someone with more experience can shed some light on this...

-Ryan

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