E30 Zone

Hi all,

I'm doing the M50 swap over next week and just want to be sure that my gearbox is going to fit onto the engine with my M20 flywheel etc.

All I need to know really is what box is on my car, and if my diff is a proper medium case. It's supposed to be an LSD, but i've only driven it on and off of the trailer. Bought it as a project last month.

If it is an LSD, I'll be taking it out and replacing it with an open diff so I can weld it. However if it is an LSD, I might mess with the ramp angles and plates etc.

Thanks in advance

Medium case diff has 8 bolts holding the rear plate on,the smaller diff has just 6 bolts.Short of putting the two side by side,this is the easy way to tell them apart!

Gearbox is a little more difficult,as we do not know what engine you are yanking out to fit your M50.....

The earlier M10/20/30 range of engines sit at a different angle to the later M40/42/50/52 range of engines,and this dictates which gearbox you need to use.
Even here,there are traps for the unwary,as Getrang 240 was built to suit both M20 and M40/42,and it is very difficult to tell the things apart off the engine they came with.

I used an ex M40 Getrang 240 with a 320 propshaft and 320 shift linkage and a 1.9 Z3 gear lever for my M50 conversion.

willnz wrote:Impossible to tell if it is a LSD from a pic. You need to check if the diff tag has a 'S' on it.

Perhaps try the 'turning one wheel' trick?

Mainly wanted to know if it was a medium case or not. Will check if its a real diff when I remove it and have a peek inside.

The engine is a 2.5 M20 if that helps...

Driftybolox wrote:
The engine is a 2.5 M20 if that helps...

That will be attached to a Getrang 260 or 265,so not suitable for your M50,unless you are able to fabricate a gearbox support and mess about with the linkage,of course.

Most dump the dual-mass fly from the M50,and use the M20 fly/clutch combo.

Yep. Sold the M20 without flywheel and starter.

Well that's a fooker. How much is a box going to cost then. Might just make up a mount instead though. Got to be cheaper. I think its only the angle thats a problem so could get away with chopping and welding the gearbox support i guess

Might be worth reading this:

http://www.e30zone.net/e30zonewiki/inde ... 5x#Gearbox

Tricky choices...

Buy a ZF and a prop, or just cut and weld the existing mount and make up a linkage...

daimlerman wrote:

willnz wrote:Impossible to tell if it is a LSD from a pic. You need to check if the diff tag has a 'S' on it.

Perhaps try the 'turning one wheel' trick?

sorry to sound dumb where is the diff tag and how do I determine is its LSD or not by turning 1 wheel?

Grrrmachine wrote:http://www.e30zone.net/e30zonewiki/inde ... tification

As always Grrrmachine is here to help TOP STUFF

Thanks,

Ok, so I found these in the US. These guys use this mount with the normal M20 rubbers and don't seem to have any issues with linkage etc.
Guess the easiest solution is just to copy these.

Grrrmachine wrote:http://www.e30zone.net/e30zonewiki/inde ... tification

This does not always work though, particularly if the diff has been pulled apart in the past. I have 2 LSD's and neither have the tag.

I find the easiest way is to jack up the rear of the car and turn one wheel. If the other wheel turns in the SAME direction, it is an LSD. It it turns in the OPPOSITE direction, it is an open diff.

I hope this helps.

willnz wrote:

That's very elegant looking. The ideal box is the 260 used in the very early 24v 520i and 525i - they are so rare though.

Very nice. Shame you're in Kiwi land. Would have been round your place begging you to make me one that nice