Later model oil pump housing

[E9project]

I'm assembling my 2800 engine from parts the previous owner collected over a couple of decades. Anyway, I have a new 79 oil pump main housing and new rotors that I want to use instead of the original 71 casting (well worn from 100k miles or so of use). The 71 casting is threaded at the oil pressure relief for a male vent plug that also holds the spring tension on the pressure relief mechanism. The 79 casting is not threaded and the metal is too thin for me to cut threads and feel good about it. It is a OEM BMW casting. I'm guessing that newer M30 oil pumps must use some sort of pressed in plug to serve the same purpose as the threaded one of the original 71 casting. Has anyone seen this and if so what parts do I need to use the newer 79 housing for this pressure relief to work correctly?

The new housing has a weep hold in this passage also. I have the blue factory manual and it shows the 71 arrangement only.

Thanks in advance to anyone who has seen this problem before.

 

[Mario L.]

Your later style pump housing uses a snap ring and washer to retain the spring and plunger.

Careful with the swapping of parts . .I've once found a pump with a plunger that inserted to far into this bore allowing for an air leak to the inlet side of the pump . . resulting in no oil pressure at start up. This could only be seen with the front and rear half disassembled.

 

[E9project]

Thanks, for the reply. I found the new snap ring and an insert to hold the spring in place. I'll watch for the piston extending to far.