Driveshaft lengths & combos thread

[lukeADE335i]

As suggested in another thread, there have been a few threads with more comprehensive discussions of some of the options for driveshafts, with actual measurements & pics - one in Andy B's project thread, another we had in the M30 with Getrag 240 thread. Perhaps we can pull some of these together here & anyone with further info to add can do so. It would be good to get a comprehensive list of driveshaft lengths and combos.

My post from "The m30 with Getrag 240 thread"

When doing my M30 swap, between me & my Dad we had a large number of driveshafts for comparison. Here's the pic:


numbered 1 -> 8 from left to right

1 & 2 - e30 M20 automatic driveshafts
3 - e30 M10 automatic driveshaft
4 - e30 323i M20 manual drive shaft (G260)
5 - e30 320i M20 manual drive shaft (G240)
6 - e28 528i / 535i M30 manual drive shaft (G260)
7 - e28 520i manual drive shaft (G260)
8 - e30 318i manual driveshaft (G240)

Of note are that the front sections of the 320i driveshaft (G240) and the e28 M30 driveshaft (G260) are the same length, the difference is in the rear section of the driveshaft & output flange size.

The front sections of the 318i (G240) and e28 M20 driveshaft are also the same length, just the e28 is a thicker, heavier driveshaft.

323i e30 drive shaft is approximately 1 inch shorter than the 320i.

The automatic drive shafts do differ in length, but are all too short unless you had some radically far back engine position (with modified firewall).

That said - could a 4 cylinder automatic drive shaft work with a G265? Never seen one for a length comparison with the G260 but they are meant to be longer.

Make of that what you will :)

Andy B's posts from "New name and new engine for Mina"

While I'm waiting for the engine mounts and e34 oil pan to arrive in the mail, I've been working on getting other areas sorted out for the m30 swap. I threw new plugs in today that arrived in the mail, as well as removed, cleaned, lubricated, and re assembled all the shift linkage. I know I'll have to cut and weld it, but I figured I might as well get it all clean so I'm not working on grimy parts. I also sorted out the parts that are getting swapped (e28 radiator, 3.25 diff, etc), from the parts that aren't getting swapped (motronic 1.0 harness, sensors, etc) and cleaned the garage, so when it comes time to actually swap the motors I'm not tripping over extra parts everywhere.

I then focused on the driveshaft. I know the g265 is longer than the g260, and from what I've seen in other builds, shortening the driveshaft is mandatory for the g265, regardless of engine mount position. Between an extra 325i small flange driveshaft, 325 auto driveshaft, and the e28 driveshaft I pulled out, I have an assortment of different length driveshaft sections. I decided to measure each shaft section (from flange to the center of the u-joint):

e30 manual front: 22.5
e30 auto front: 16.5
e28 g265 front: 21.25

e30 rear: 29.5
e28 g265 rear: 32


I noticed that while the 325i auto driveshaft is 4 inches shorter, that difference is all in the front half, while the rear half is the same. Meanwhile, the e28 front is in between the length of the e30 auto and manual shaft, with a rear section that is longer than e30 rear section. This means I have 3 different front shaft lengths, and 2 rear shaft lengths to mix and match, as well as the splines that allow for about 2.5" of adjustment while still maintaining adequate spline engagement.

I swapped the shaft sections between the auto and manual, which gave me two different lengths, both shorter than the standard e30 manual driveshaft.

The stock e30 shaft is about 57 inches (+/- about 1 inch).

With the e28 front shaft matched to the e30 rear shaft, it measured out to 56 inches(+/- about 1 inch), which is only 1'' shorter than the e30 shaft. Every account I've seen needed to remove a hair over 2 inches, however, so I suspect this will still be too long to squeeze in between the g265 and the diff.

The other pair was the auto 325 front half and the e28 rear half, which game me a 53.5 inch length (+/1) one inch. This means I can safely stretch it to about 54.5 inches (and probably a little longer), which puts me within 2.5 inches of the stock e30 shaft, which sounds perfect! However, there is a problem with this combination... can you guess what it is?

Top: e30/e30
Middle: e28 front/e30 rear
Bottom: auto e30 front/e28 rear



The shaft that comes closest to the ideal length will have the CSB about 2.5 inches too far forward. The pedestal that the CSB mounts to give you some adjustment, but not 2.5 inches worth. However, while I can't cut and weld up a usable driveshaft at home, I can cut and weld up a bracket to mount the offset CSB. I'm thinking of using this same basic approach, but welding in some cross bracing, and throwing it through the powder coater/oven to make it a little more presentable.



I'm going to hold out hope that I can mount the engine forward enough to at least squeeze the e28 front/e30 rear shaft combo in, but if not, I'll just fabricate a bracket for the auto front/e28 rear csb out of metal from the scrap metal pile and see how that works out. If I have a vibration issue at normal driving speed, I'll bite the bullet and pay to have the 87 eta large flange driveshaft that's in the car shortened and balanced.

[Andy.B]

After a job change and a move, I finally got back to work on the m30 swap. I got the engine mounted in place this afternoon. I will hopefully figure out the driveshaft situation soon. I'll make sure to update this thread if I am able to make a driveshaft fit using unmachined parts.

[Mr. Burns]

good idea for a thread
there's a lot of info out there, but a lot of "hit and miss" info.

I want to have all my parts in order before I go and throw them on the car.

ideally i'm looking for a e28 535 front part DS to mate with my oem e30 M20 DS, but i'm SURE there are plenty of other options that could work without breaking the bank and getting a custom DS fab'd .

[CorvallisBMW]

My solution was easy:

m30b35 on Good & Tight mounts
g260/6 with swapped output flange (from a g260)
Stock m20b25 manual trans driveshaft

Everything bolts up perfect.

I also believe you could use the stock large 260/6 output flange and large-guibo m20b27 manual driveshaft.

[ThatOneEuroE30]

I also believe you could use the stock large 260/6 output flange and large-guibo m20b27 manual driveshaft.

I used a m30b34 with the e28 260/6 and the 87 325e which is the large guibo driveshaft. I had to shorten it about 2 inches to fit in my euro spec 320i

[kamotors]

stock driveshaft, revshift adapter guibo, done.... no swapping flanges just pop in their big flange to small guibo and your good to go.

I've run it upto 25psi of boost and its holding up great

[hotdish]

My bolt in combo:
- '88 m30b35 on Garagistic Mounts
- '88 g260/6 with small flange swap
- '85 323i manual driveshaft
- '92 e30 4-bolt medium case diff

I used a m30b34 with the e28 260/6 and the 87 325e which is the large guibo driveshaft. I had to shorten it about 2 inches to fit in my euro spec 320i

I thought all e28's came with the longer 260/5?

[ThatOneEuroE30]

My bolt in combo:
\


I thought all e28's came with the longer 260/5?

you might be right. I get the two mixed up all the time

[Mr. Burns]

stock driveshaft, revshift adapter guibo, done.... no swapping flanges just pop in their big flange to small guibo and your good to go.

I've run it upto 25psi of boost and its holding up great

I've checked the revshift website and I'm not seeing this.
Is this a good alternative to getting a custom driveshaft balanced from 2 different cars?

[kamotors]

bolt it in and be done
http://www.revshift.com/product-p/pfx-24v.htm

[Mr. Burns]

This will work with a m30 g 260 oem flange? It's listed to work with m5x/s5x swaps?
unless the Mx/sX output flanges are the same size as the M30's....I could see this as being a fairly cost effective and great alternative

[kamotors]

This will work with a m30 g 260 oem flange? It's listed to work with m5x/s5x swaps?
unless the Mx/sX output flanges are the same size as the M30's....I could see this as being a fairly cost effective and great alternative

same flange its what I'm using on my car

[Mr. Burns]

Why don't more e30 m30 swap guys do this??
Awesome thanks for the info!

[lukeADE335i]

Because the Redshift adaptor flange is a relatively new part, and there's some controversy around how well they work & the longevity of the drivetrain if using them on a daily drive. Do a search on the forum.

[Mr. Burns]

Ah. I just did.
Dream fizzles away