Can anyone identify this water pump? (M10 but not an 02)

[JamesRamsay]

Well, I've bought the wrong water pump. Graf brand, obviously an M10 water pump, but the pulley flange is too big and the bolt holes are drilled in the wrong spots. They're at 12, 3, 6 and 9 o'clock, whereas all the pulleys I have on hand have more like a 2, 4, 8, 10 o'clock pattern. RealOEM claims that basically every M10 engine uses the same water pump, so no help there. Does anyone here recognise what car this might be suited for?

 

 

(Unfortunately there are no identifying numbers on the pump itself other than R605M and RAO on the boss of the flange, and Google doesn't have anything to say about those)

 

EDIT - Here's what my pulley looks like, for comparison:

 

Edited September 21 by JamesRamsay

[dlacey]

I have only seen that flange on the 520i ...but this is a carb pump...so I guess early 520 or 320

[Mike Self]

There was a 518 that used an M10 engine, as well as several E21s (none imported to the US) that also used a carbureted M10 engine, as well as the M10-engined E30, one version of which was imported to the US. 

 

Hard to believe that BMW would have unnecessarily complicated their spare parts inventory by using two different water pumps without a good reason.  Did any of those non-2002 M10 applications have a thermostatically controlled fan?  If so, that might be the answer...

 

mike

[2002iii]

You could try swapping the flanges if you have access to a hydraulic press.

 

Reminds me of the time I thought I got a new 2002 water pump for cheap, turned out to be for an e30 318i.  The flange sticks out about an inch further on an e30 because they had a fan clutch and actual radiator clearance.

 

 

[tzei]

E21 4 zyl

[visionaut]

What’s the bolt circle diameter? It looks larger.

 

I was once looking to run one those ultra-thin 1” flexible aluminum fans (in pursuit of rad clearance), but they were all 3 6 9 12… and at our bolt circle diameter and hole size, you can’t fit both patterns on the fan center. Ask me how I know…

 

[JamesRamsay]

Thanks everyone, as suggested I believe it is an E21 pump. RealOEM suggests it was found on 1.8 and 2.0L M10s on E21s, E12s and some early E28s. It seems like the Bavarian Boys switched to the North, South, East, West bolt hole configuration for their late '70s selection of water pump flanges, and then thought better of it and went straight back to the flatter x-shape with the E30.

 

I'm going to mock things up and see if I can't figure out a way to use this pump. I have an E30 pulley which I might be able to drill new holes in, and it might need a spacer to get the belt alignment right. And if I can't use it, at least I know what it is so I can sell it 👍