M20 insight...

[MrNatural]

I'm swapping a B27 motor out for a B25. My mechanic got to the oil pump and there's a slight difference with the relief valve. There's a hole in the b27 bottom but not the same on the B25. Is there a different valve? Thought all pumps were the same? Also noticed the oil tube was moved further back on the B25 and the B27 dip stick is too long for the B25, anything to that? I've read up what I could but haven't come across anything for this. Any help is appreciated gentleman!


B27 mount

B27 mount

B25 mount with spindle


B27 oil tube


b25 oil tube

[digger]

That b25 from a 5 series ?

[MrNatural]

I'm wondering that myself. I bought it used from a puller and sent it to a machine shop for a refresh.

[kronus]

I believe that might be an iX block.

[MrNatural]

Am I fubarred if it is?

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[cheffy30]

that b25 is not in my e30

[kronus]

Am I fubarred if it is?

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yes unless you want to take everything apart and
- drill and tap a hole for the oil pressure relief valve
- swap to a regular M20 intermediate shaft
- improvise a dipstick relocation approach (you may be able to use an E34 M20 oil pan, they have the dipstick in the pan)


if you do not do those things and start the motor as-is in a RWD configuration, you will have no oil pressure because the oil pump spins the other way.

[kronus]

also, yes, it is an iX block. you can see the additional oil pan bolt holes near where it says PUMP in blue.

[MrNatural]

Well damn! Not what I wanted to hear...anybody need a good ix motor? Guess I'll look for a short block...

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[325e '87]

Sorry to read about your situation.

But, couldn’t you use your b27 block/crank/rods? I know you have some invested into that b25 block but I believe you could throw together a stroker and wont need to find another engine.

Think about it and research it, I haven’t done it but my son and i are collecting parts to build a 2.7i this summer.

[MrNatural]

That's what I would do but the B27 is cracked.

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