M30B35 Swap

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santiagoe12
Posts: 3
Joined: Sat Dec 10, 2016 7:37 pm
Location: Montevideo, Uruguay

M30B35 Swap

Post by santiagoe12 » Thu Mar 26, 2020 12:18 pm

Hi guys,

I am planning a M30B35 (´91 euro e32) swap in my M20 e12, and I have come across a few doubts as I am not familiar with M30s.

I understand that I sould use an e12 oil sump and pump. About the pump, should I use the B35 main body and a e12 pick up tube? I have read here and other forums about some oil pressure issues but was unclear. I have a 528I sump and pump for this aspects of the swap.

At the time I´m only cleaning and sourcing parts, and plan to refresh everything in this engine. But for a future stage, maybe next year if this coronavirus allow us, I plan to add a turbo system. In order to drop a few points the actual compression ratio (maybe form 9:1 to 8,6:1), I would like to use a thicker MLS head gasket. Can someone confirm the std head gasket thickness? Also, I searched the forum but didn´t find much info about turbos and would like to know of experiences with cylinder head bolts. This isn´t a race car, it´s a daily driver and will spend most of the time in the city under 3k rpm. Turbo pressure won´t be beyond 0.6 bar. Will the standard head bolts hold up fine? I was told from "experts" that intercooler wasn´t necessary for my goals, but I would like to be safe and keep intake temps as low as possible with a front mounted intercooler.

Other thing that I would like to know, is if I can use the e32 radiator. I only took a few measures and it seems it would fit. I know that you probably would recommend me to use the e12 radiator, but understand that I am in south america and it is a PITA to get parts. This radiator was included in the engine so I would save around 350 $ if I can use it.

Well, thats it for now. Will upload a few pics as soon as I can.

And sorry for so many questions in a strange english!! :roll: :roll:

Regards

Santiago

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keehn
Posts: 88
Joined: Tue Oct 01, 2019 5:14 pm
Location: Martinsburg, WV

Re: M30B35 Swap

Post by keehn » Thu Mar 26, 2020 7:27 pm

Santiago,

The E12 oil pump and pickup tube are integrated into a singular unit as shown below.

Image

Image

I'm not sure about the head gasket thickness, but I would ask the MLS vendor to ensure their gasket will fit your application. As for head bolts, I would HIGHLY recommend ARP head studs. The OEM bolts are reusable, as they do not stretch like a TTY bolt. That said, if I was in your shoes, I would not trust OEM in this situation.

I'm not sure about using an E32 radiator but you CAN use an E28 radiator. I have seen all-aluminum E28 radiators for sale. However, since E32's did come with the M30 as an option, the E28 MIGHT be an interchange part. I would suggest you check out www.realoem.com and look up both models to see if they use the same radiator.

And yes! Please post pics when you can; We always enjoy seeing fellow Fivers cars :D

Mike

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Lock
Posts: 353
Joined: Sun Oct 04, 2015 1:51 pm
Location: Washington state
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Re: M30B35 Swap

Post by Lock » Tue Mar 31, 2020 1:53 am

The reason for swapping the oil pump/pickup is because the e34/e32 sumps are different to fit the subframe, and you'll need to transfer your e12 sump and pickup, they will swap between blocks just fine. I think it's covered in our first fives FAQ on engine swaps.

Looking at my e34, which is similar to the e32, the e32 radiator is physically about the same size but won't mount. If you are able to fabricate up your own mounts you could make it fit.

As Mike said, the e28 radiator also fits with a few minor mods, either the standard version or aftermarket all aluminum radiator.
1979 528i 5-speed conversion G260/6, Motronic 1.3 179
1980 Honda CX-500

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keehn
Posts: 88
Joined: Tue Oct 01, 2019 5:14 pm
Location: Martinsburg, WV

Re: M30B35 Swap

Post by keehn » Tue Mar 31, 2020 11:51 am

Lock, thank you for the clarification; I was not thinking about differing subframes.

Heh, I'm waiting for someone to ask how to fit an LS engine into an E12...seems to be the most popular engine swap in vehicles in general :lol:

Mike

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