2.8L to 3.5L

[Vintagemotorwerks]

I have a question for the two lads who wrote the article on the 2.8-3.5l conversion. I saw that you said the 89 and up 3.5L needed extra things. Can someone elaborate on what is needed? I took a complete 3.5L out of a 1989 735i among with harness and motronic and the clutch kit out of a ‘87 535i. What else do I need? All feel to chime in. Thanks guys

[Mike W.]

I didn't write it but it probably refers to the mounting bosses on the block and the need for a different motor mount bracket. I know that's an issue with E28s although they use different points than E12s. Koala Motorsports has adapters for E28s but those are different than E12s of course. Might be worth a call. IIRC the right side mount is the only one that's a problem.

http://www.bmw-stuff.com/proddetail.asp?prod=m30r

[HB528i]

The Koala adapter will work great. My 88 b35 didn’t need the adapter but an 89 will.

[Vintagemotorwerks]

So is the motor mounts what’s different or is the actual bolt pattern to the block different between a 1988 and 1989? If it’s just the motor mount that’s different then can I just get the mount from a 1988 or older and bolt it up to my block? Also thanks for replying

[HB528i]

The lugs on the block are missing in two places on the 89 so a stock bracket is not secure. The adaptor uses a nearby lug to add strength.

[Vintagemotorwerks]

Aside from the motor mount brackets, is there anything else I need to have?

[Vintagemotorwerks]

To add to my previous question, is the a different ECU between automatic and manual transmissions on the M30B35 engines? I pulled the engine and ecu from a 735i auto but I plan on using the 5spd from a 535i. Will my 735i ecu work or will I have to use a ecu from the 535i?

[HB528i]

I would look up the part number of the ecu in RealOEM.

[Mike W.]

To add to my previous question, is the a different ECU between automatic and manual transmissions on the M30B35 engines? I pulled the engine and ecu from a 735i auto but I plan on using the 5spd from a 535i. Will my 735i ecu work or will I have to use a ecu from the 535i?

I don't believe so. Everything you wanted to know and more about the swap is here, https://www.mye28.com/viewtopic.php?f=3&t=60306

[Vintagemotorwerks]

Thank you mike!!!