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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

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

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

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

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.

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

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

Vintagemotorwerks wrote: Sun Aug 30, 2020 2:04 pm 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

Thank you mike!!!