engine and drivetrain Rebuilding Oil Pump

[echappe]

Has anyone had any luck with just replacing the inner and outer rotor on an oil pump rather than buying a new one?

[Rocan]

The rotors don't wear very much, especially if the engine has consistent oil changes. The issue is usually the relief valve getting stuck in the bore as the aluminum casting wears. I believe Metric Mechanic's refurbished oil pumps have the hole oversized and a bronze bushing pressed in to cure the issue. One day I'll play around with doing exactly that. 

[Preyupy]

if the pump is worn it is usually the aluminum housing where the outer rotor runs.  The only time I have seen a badly worn inner gear and rotor was after an engine blow up and there had been pieces run through the pump.  If the housing and gears look good, run it!  When they were only $45 it was not worth even thinking about the wear but now that they are over $300 I have a good look and reuse the ones I can.

[TobyB]

 

The rotors don't wear very much,

...but on an abused (too few oil changes) the housing and outside of the orbital gear will scar- as will the sides.

You can use the later steel plates to clean up side wear,

but as Byron notes, if the housing gets gouged up, it's pretty much done.

Honing and polishing the relief bore and piston's always a good idea- the extra clearance

is probably more helpful than the surface finish, but a little extra leakage doesn't matter that much.

 

Likewise, I find myself saving pumps now that I wouldn't have looked at twice even 5 years ago...

 

t

[kbmb02]

Has anyone had any luck with just replacing the inner and outer rotor on an oil pump rather than buying a new one?

 

Yes. And, sometimes, if all other components measure within spec, one can replace the pump housing for a decent price (when you look at the list of parts separately, it's the long M10 pickup which is most costly). -KB

[FB73tii]

And, sometimes, if all other components measure within spec, one can replace the pump housing for a decent price

Hey that's a great tip. Did a quick search, here are relevant part numbers and online BMW prices:

 

OIL PUMP HOUSING

11411267199

$51.36

INTERMEDIATE PLATE

11411263218

$4.75

[jgerock]

Thanks for the tip.  I purchased some of the internal parts from BLUNT and have 3 pumps waiting for some love.