Driveshafts (half shafts) difference on e30

[pianist]

Hi all
i have heard that there is difference between 4 cylinder (small case) driveshafts and 6 cylinder (medium case) driveshafts but can't get definitive answer anywere as of what actual difference is: length, thickness...?

I would realy appreciate If anyone could tell me how to tell them appart and what price am I looking at.

I have swaped my small case with medium case and it seems to fit fine but I read somewere that small case shafts are longer and not compatible with medium case diff as in it will not last long, anyway I am looking for something stronger as I have fitted m30b35 engine. Any help appreciated
Thanks

[jmc330i]

Driveshafts are the same (only difference is the abs ring). The difference between small case and large case diff is taken up by the diff output flange not the driveshaft. The small case output flange is longer.

[maxfield]

As said above, only difference is an ABS ring.

The only you'll have to do is shorten your prop slightly fitting the large case diff. This is done by a lock nut in the middle of the prop shaft. It's on splines, so undo and shorten and then re-tighten.

Standard E30 shafts will be perfectly fine with an M30 fitted. Although a small case diff doesn't enjoy sn M30

[tomson]

They are different, the 6 cylinder shafts have thicker/stronger UJ's on each end.

The overall length of the shafts is the same for all of them, the smaller case diffs have a wider output flange to make up for the loss in case size as mentioned above.

The shafts are interchangeable and any E30 shaft will fit any E30...

[tomson]

When I say 6cyl I mean 325i's, 320i's generally have the smaller 4cyl shaft, even if they have ABS...

[pianist]

UJ's as in CV joints?
Are they interchangeable between drum and disk setup?

Thanks for your responses so far, already saving me money

[maxfield]

That's the first time I've ever seen anyone mention that 325i shafts are different, everyday is a school day.

Yes they are interchangeable between drum and disc.

[tomson]

UJ's as in CV joints?
Are they interchangeable between drum and disk setup?

Thanks for your responses so far, already saving me money

Yes the UJ's as in CV's are larger on a 325i/M3 driveshaft. If you've got an M30 powered car and you like diffin it I would definitely get a pair of the larger shafts on it.

To fit the larger 325i shafts to a drum set up I think you might need to remove the ABS rings, but I'm not sure on that, I've never really messed with drums. Ideally you want to junk the drums and fit discs....

[pianist]

That's great
I am ditching drums mate that's why all the questions that I have.

So I can purchase only the bigger UJ's and fit them to the shafts that I have or is it not financially feasible? Also is it just outer UJ's that are bigger or inner ones too?

[pianist]

Also just to clear it up the actual shafts are same size it's the CV joints/ UJ's that are different sizes?

[jmc330i]

Never heard of that before. All the part numbers match up from 316i to M3
If it is the case, the 'smaller' UJs coped with my S50B30 conversion without any hassle...

[tomson]

So I can purchase only the bigger UJ's and fit them to the shafts that I have or is it not financially feasible?

Not sure on that, I'd just buy a pair of 325i shafts complete.

[tomson]

Also is it just outer UJ's that are bigger or inner ones too?

Both ends are wider.

[tomson]

Also just to clear it up the actual shafts are same size it's the CV joints/ UJ's that are different sizes?

They are the same thickness but I don't know about length, they may be different lengths because of the UJ's...

I think I've got both types at work, I'll take some photos tomorrow so you can see the difference...

[tomson]

Never heard of that before. All the part numbers match up from 316i to M3

There are often errors in the ETK.
One I came across last week is it lists an M50 crank sensor being the same as an M52 sensor, but they are not

[pianist]

Also just to clear it up the actual shafts are same size it's the CV joints/ UJ's that are different sizes?

They are the same thickness but I don't know about length, they may be different lengths because of the UJ's...

I think I've got both types at work, I'll take some photos tomorrow so you can see the difference...

That would be grate. Also could you measure the thickness/width of UJ's?
Thanks for your help

[tomson]

Hopefully these work...

[tomson]

The lower one I marked '318' actually came from a 320i Touring with ABS...

[maxfield]

Massive difference! I had a few shafts lying on the floor and never even noticed.

[jmc330i]

Massive difference! I had a few shafts lying on the floor and never even noticed.

Can't say I've ever had more than two side by side, but I never noticed either.

As I said above, I used the rear arms and shafts from my old 318i touring on my S50 conversion and never had an issue and going by the above, they were probably the smaller type.

A mate bought an M52 touring based on a 318i and that gets properly abused... only ever broke the diff while drifting.

[pianist]

The myth is confirmed

So I guess I will keep my slimmer ones for now as if s50 didn't brake em I think I'll be quite safe with m30 and it will save me some pennies to spend on something I need for my more door

Thanks for pointing it out to us tomson

[Brianmoooore]

ETK lists no less than four different driveshafts for the 318i with discs. ABS and non ABS, and manual and auto. Both manual driveshafts are listed as weighing the best part of a kilo heavier than the auto versions.
Only one listed for the 325, and that's the same as a manual 318i with ABS.

[jmc330i]

I was searching under 318i with ABS as that's what I used on my conversion and explains why I only found one part number.