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M30b25 to M30b35 Interchangeable parts?

Posted: Thu Oct 20, 2016 3:41 pm
by TTR&D
Hi all.
I am a newbie here and live in Norway.

Hoping some members here can help me.

I have a 77 518 I am converting to a M30b35 engine with moronic 1.3

I purchased the b35 engine from 88 e34 cheaply, but it is missing some parts.
Alternator
Starter
Servo pump
Injectors
Fan

I do know I need the oil pan and pickup from a e12/28 m30 engine.

i can get another cheap engine from a e12 but it is a m30b25
Can I use this engine to replace the missing parts on my b35 engine?
Guessing the injectors won't work, but the other parts?

Regards Andrè.

Posted: Thu Oct 20, 2016 10:33 pm
by RonDwyer
I do recall not being able to use the B35 power steering pump becasue it bolts to the oil pan. My 77 has all the 530i pump and alternator. I created a power braking system from the B35 donor car, no more vacuum booster.

Motronic, not moronic :D

Posted: Thu Oct 20, 2016 10:38 pm
by Qwodracer
RonDwyer wrote: Motronic, not moronic :D
Not when you're frustrated!

Posted: Fri Oct 21, 2016 2:48 pm
by RonDwyer
L Jetronic, now that's frustrating!
But not as much as a balky CIS system
D-jet was fairly easy to maintain

Posted: Fri Oct 21, 2016 5:01 pm
by TTR&D
😂😂😂 well moronic would explain a lot of things😂😂🙈

Thanks for the help.


It has been brought to my attention that the e12/e28 m30's bolt their psp to the oil pan.

But if I use oil pan and psp from the same engine it would work?

can I use b25 pickup on the b35 oil pump? Thinking on the relieve valve and the oil filter face down on b35 and up on b25.

Bare with me on my English 👍

Posted: Sat Oct 22, 2016 12:09 pm
by RonDwyer
How about this:
Look at your engine today.
You need to re-use the oil pan
Look at the engines others say will work.
Make sure the new oil pan clears the subframe.
Put the 2 pans side by side while out of the car.
Now plan to use just about everything you already have.
Including the oil pump.
PS pump does bolt to the oil pan
It is not interchangeable with the new one
And, the new alternator does not bolt up with the old pan either.
The brackets and flanges are all just a bit different.
My project was a 77

Re: M30b25 to M30b35 Interchangeable parts?

Posted: Wed Nov 02, 2016 2:39 pm
by CabbageFumes
TTR&D wrote: I have a 77 518 I am converting to a M30b35 engine with moronic 1.3

i can get another cheap engine from a e12 but it is a m30b25
You need the oil pan, oil pump pickup, all of the brackets and mounting hardware for the alternator and p/s pump, and the water pipe from the rear of the head from the donor M30.
You will also need the front subframe. The one in your car is for an M10 engine, and won't work with an M30.
Also, unless you have a very early M30B35, the motor mounts won't work. You will either need adapters, or you need to get a block from an earlier M30B34, then swap everything over. If you change blocks, you'll need to change all the bearings and rings, which means a complete rebuild.

I think this is more work than you were expecting, so you need to really think about if it's all worth it.

Posted: Thu Nov 03, 2016 11:01 am
by CabbageFumes
I re-read your original post, and noticed that the car you bought the B35 from was an e34. All e34 M30s used a block that will require adapter plates to use the e12 motor mounts. Honestly, it would be easier to just find a local M30B34.
It puts out the same horsepower as a B35, and will bolt right in. You can use the B34 harness, or you can swap all the B35 harness parts over to the B34, but there won't be much benefit going to 1.3.
The only thing I noticed that was a benefit about 1.3 was a slightly smoother idle. I think a Euro B34 is a better choice in an e12.

Posted: Thu Nov 03, 2016 2:12 pm
by TTR&D
Hi.

Thanks guys.


So from what I can understand all the eksternal parts from all m30 engines will bolt up on the m30b35 engine if I use brackets from the engine I use the parts from?

B34 would be a good choice and in regards to performance it would be equivalent to the B35.
But these engines are not that easy to get here in Norway.

So a B35 came for sale at a nice price and I bought it.

I am aware of the work needed to fit the b35 in the e12 chassis.

I have the m30 subframe
Fabricating brackets to mount the late B35 engine in the e12 is a easy task.

I am not in a hurry and plan to do it the right way and only do it once.


Engine will be inspected re built. Someone know a place they sell brand new eksternal bolts for the m30?

Front and rear will be dipped, painted, new bolts, bushings and brakes all the way.

I am not doing this to earn money on it... it is only to do it the way I like
:D :D

Posted: Thu Nov 03, 2016 5:14 pm
by CabbageFumes
Ok sounds good.
As long as you use the e12 M30 pan and oil pickup, all you need are the brackets from the b25. M30B35 P/S brackets require a M30B35 oil pan. Any M30B34/32/30/28/25 bracket will work with an e12 pan, but will not work with a B35 pan.

Confused yet?