Lubricating oil pump service life?

[JMBT]

So I bought a new oil pump today. The only thing I could get NX was the new style with the threaded regulator plug. It did not come with a shim Kit. So I spent about an hour on the phone with Cummins customer care. I talked to a really nice, level 3 tech. He said the new style pump does not get adjusted with shims. Cummins has changed the idler to crank backlash from .007-.018” on the old style, to .003-.022” for the new style. If the pump doesn’t meet that when mounted without shims, you have to buy a new pump. So.... I thought that was interesting. You can still by the old style pump and shim Kit, but it is RX.

Also interesting, the customer care guy said he has never heard of an oil pump failing unless debris goes through it. That most people just end up replacing them as preventative maintenance.

Take it all with a grain of salt. Just thought I’d share.

[Rawze]

I, personally would have taken that tech's word with a grain of salt. It may be acceptable for warranty purposes, but I would tend to disagree when it comes to least wear vs. oil viscosity.

0.007" and less, is definitely below the typical gear lash clearance for the size gear + viscosity oil being used in the engine. As a general rule, that size gear would dictate 0.010" - 0.016" if I had to guess at it based on my many years and overall experience dealing with industrial machinery.

just my own opinions/thoughts any ways. That low of a clearance would also likely cause some gear whine out of it too. Hopefully its clearance is not at the bottom end of that scale. if i owned it, I would have shimmed it anyways (and ensured there was no problem with doing so) if it were less than about 0.010" gear lash, but that is just me.

[dhirocz]

Part number of the pump? I just spent some quality time this past weekend on quickserve making up a nifty parts list for my IFSM and looked up a new pump and turbo supply lines while I was at it. I dont remember seeing anything of the sort when I looked up a pump.

My pump still looked fine at 685k when I last had it off. Im over 850k now, and Ill be replacing it if nothing else as a function of maintenance when it next comes off, if for nothing else peace of mind.

Im assuming this was for an 871? Was there a reason given justifying the new design? Lastly, what did they get pricewise for a new one?

[JMBT]

Rawze: I have not installed the new pump yet. I did keep the shims I took out from the old one. I’ll check the clearance when it goes on and maybe I can use the shims if it is too low.

Dhirocz: my motor is a CM2250, but I think that they are the same as the 871. It was $835.00 brand new, at Cummins in Tulsa, OK