bmwe21.net forums

Hi, I am just starting out with my planning/research for a restoration and conversion of E21 model to a M20B25 engine. Ideally I'd like to start with a 323i, but prices have sky rocketed of late and they are out of my budget.

As a result, the next best (I think) would be to start with a 318 5-speed manual (non-dog leg pattern). I've found some good threads on converting 4-speed 320i's, but none on the 318. My understanding (and I'm still learning), the later E21's (318 and 323) had the same front subframe, so that will not need to be changed. My main question is, what about the 5-speed gearbox from the 318i, is it the same as the 323 and therefore could be used for this conversion without any other changes (i.e. prop-shaft, etc.)? I see that gearbox model designation for the 318 is Getrag 245/4 BN and the 323 is Getrag 245/288 GC, but am not sue what the difference is between the two.

Are there any other aspects I would need to consider?

I also assume if I swap in a 323i M20 without any modifications?

Afaik the gearbox bolt pattern M10 and M20 are different and also the M10 sits 30 degree canted while the m20 sits at 20 degrees.

And the 4 cilinder subframe is different to the m20 6 cilinder subframe. But you can swap it.

Well, guys, about 5 months ago, I purchased this 1982 318i 5-speed. Sorry its taken me so long to post about it.

It’s in remarkably good condition inside and out for its age. I have been using it as a semi-daily driver and loving every minute, even though it’s probably down 15-20hp and the suspension (especially the front) is pretty much shot!
The plan is to do a full, street biased resto-mod to it including:
• M20B25 swap (Some light mods – Chip, exhaust, etc.)
• LSD
• Full suspension rebuild (hopefully with 323i rear sub-frame, arms and brakes), with Bilstein B8 shocks and H&R lowering springs
• Brake upgrade (TBD)
• Full interior retrim
• Colour change (Zypressengrün Metallic)
• A set of 7 & 8 x 16’ Alpina wheels
I know I’ve probably gone the most difficult route, but where’s the fun in doing it the easy way! At least I have a very clean and straight base to start with.
I’m really looking forward to getting started, I just have to sell my current toy to fund the project. I’m also looking forward to sharing progress with this community and getting lots of great assistance along the way.
I also plan on joining the local BMW club, so if there are any Brisbane-based e21 owners, please reach out.

Nice, congrats! Feel free to open your own topic in the owner's gallery to keep us updated, and please spoil us with lots of photos!

Fully agree, the project is nice and defo easier with a good chassis as a basis, that usually is the largest part of the project. I can fully understand your plans, too!

We used to have several members from Brisbane but I'm not sure ifg any of them is still actively looking here.