Will a late model M20 pump work for the M42?

[JP 91iS]

I got a never-used pump from another member of the forum, but it looks like he originally ordered the wrong pump.



The one on the right is the pump I pulled from the car, the one on the left is the new one. The new one does not have the nipple for a return line. From searching around I think this pump I bought is for a late model 325 (not sure on i or e).
I was thinking I could either:

A) Switch the new pump over to the assembly from the old pump.
B) Jimmy-rig some kind of hose connection nipple for the new pump assembly.
C) Route the return line into the tank through another spot.
D) Sell the new pump and buy another new pump that's built for the M42.


So in order to decide what I'm going to do I need to know if the pump itself would work for the M42 since it was built for the M20. What do you think?

[Deftones]

i think the best thing to do is testing if the pumps powers are equal. You do this by turning them on in a cup of water and looking how much time them spend to putting all the water off
then, if the pumps powers are equal then you put the new pump with the old flange and it's ready to be fitted in the car

[gearheadE30]

The actual pump itself inside the M42 housing can be purcased for $40 at NAPA. Just swap that back into the original housing. You will need to solder the connectors, because I believe they are a little different.

[1991 E30 M42]

From what I understand, the 325 has 2 pumps, one is to move fuel from one sump to the other and thats what the other nipple is for.

[JP 91iS]

The actual pump itself inside the M42 housing can be purcased for $40 at NAPA. Just swap that back into the original housing. You will need to solder the connectors, because I believe they are a little different.

Yeah I'd like to do that, but my old pump assembly had more issues than simply a failed pump.  The plastic/rubber seal rings between the assembly pickup tube and the pump output tube was shot.  I guess I could use the one off the new assembly, but optimally I'd like to resell that. (plus I tend to be a bit snobby and not trust the aftermarket stuff.  Unless it was made by an OE manufacturer : bosch, vdo, etc)

From what I understand, the 325 has 2 pumps, one is to move fuel from one sump to the other and thats what the other nipple is for.

The one in the picture with the extra nipple is my old pump, from the 318.  The extra nipple is the return line into the tank.



I've decided to go with option D and sell the unit I bought and pickup a new unit that's designed for the car.  Thanks for the responses.