520/6 + G265/5 gearbox + G265/6 driveshaft ?

[Marcus]

Hi all,

Glad to be in the community. I am working on my project as follows,

Chassis: 1980 E12 520/6 3hp22 (factory setup)

Project
-engine: modified M20B27
-gearbox: G265/5 CR, aka Dogleg (come alone with gearbox itself only, don’t know what original donor car is).
-bellhouse: is compatible with M20 engine.
-pedal set: from a early E12 520i (m10)
-shift assembly/ driveshaft: from early e24 633csi (e12 chassis G265/6 OD base).
-rear subframe/diff: from early E24 628csi (e12 chassis), because I like to have the disk brakes.

QUESTION:
Would the G265/6 OD shift assembly + driveshaft from the early 633csi directly fit my e12 with m20 engine + m20 bellhouse + G265/5 CR + early 628csi subframe/diff?

I know it’s quite complicated, but your valuable input would be highly appreciated.

[Mike W.]

You weren't kidding, it's complicated. Though it reminds me of some of the mix and match I've done over the years.

Now I do have some info that would be hard to come by, but mostly I'm just going off Realoem in terms of 265/5 and 265/6 fitment. The M20 wild card I don't think is an issue as while there is wide adjustment on the crossmember support mounting location, it also has to accomodate M10, M20, M30, and assorted 4 and 5 speed trannys, along with A/Ts. Plus on an E28 I had I used a driveshaft from a 528e in my 535i, both G265/6 transmissions. So at least on E28s they located the tranny in the same place.

On the other hand, I'm seeing /5 and /6 using different driveshafts in the same chassis. So that might be an issue. You do have some flexibility given that it's 2 piece, but not a whole lot. There are also 2 different guibos which are of different thicknesses. Back to driveshafts, 3HP22 and G265/6 driveshafts are interchangeable. They're slightly different, but I've swapped them both ways and had them work just fine. IIRC about an eighth of an inch difference in length.

Realoem, while not perfect, is your friend. You need to spend a few hours there checking and extrapolating.

[Marcus]

Hi Mike, many thanks for your valuable input.

I am with you that realoem is literally making our life much easier when organizing project. As you are aware, not every part is that accessible in certain area/country. So I am down to m20 because the parts and maintenance is quite common in Taiwan.

I kinda ignore the possibility that m20 engine may have different engine position with m30. In other word, it’s possible that m20 engine can cause transmission a bit forward or backward than m30/transmission. Nevertheless, I has spent many many hours on realoem, and luckily I find E12 M535i (G265/5 or G265/6) share same drive shaft with e12 633csi (26111225036 ). So I will most likely buy that shift assembly / driveshaft from the early 633csi. Bet hopefully that the m20 engine position won’t cause me too much trouble. And also hopefully the guibos of 633csi can fit my g265/5 CR transmission and fit the 628csi diff without any issue.

[tlake]

Hi all,

Glad to be in the community. I am working on my project as follows,

Chassis: 1980 E12 520/6 3hp22 (factory setup)

Project
-engine: modified M20B27
-gearbox: G265/5 CR, aka Dogleg (come alone with gearbox itself only, don’t know what original donor car is).
-bellhouse: is compatible with M20 engine.
-pedal set: from a early E12 520i (m10)
-shift assembly/ driveshaft: from early e24 633csi (e12 chassis G265/6 OD base).
-rear subframe/diff: from early E24 628csi (e12 chassis), because I like to have the disk brakes.

QUESTION:
Would the G265/6 OD shift assembly + driveshaft from the early 633csi directly fit my e12 with m20 engine + m20 bellhouse + G265/5 CR + early 628csi subframe/diff?

I know it’s quite complicated, but your valuable input would be highly appreciated.

Welcome, and that sounds like a special car in the works.

[Marcus]

Thanks tlake

It’s indeed a project with lots of effort. I am into the lighter m20 engine so need to improve the power by increasing the stroker and plus a high cam. Hope the result would be rewarding.