will the e34 zf box work on a m50 conversion

[irish320i]

lookinging at the gearboxs today i have a getrag out of a 320 and ive a zf from the 525 i took the engine out im trying to work out if the zf will fit if the change over the oput flange from the 320 box if not will this box work with the m50 engine any help would be great im fairly confused at this stage

[DanThe]

Ive read on here that the flanges are not interchangeable, but ive never tried it so couldnt give you a deffinate answer.
While your boxes are both on the floor you should remove the flanges, take some pics and post em up in the M50 developments thread

[Brianmoooore]

You mean a 320 E30 box or E36 box?
Either the E34 or E36 box can be used but I don't think the O/P flanges can be changed over. You have to use a guibo and prop flange to suit.
E30 320 box will fit, but is weaker and will be rotated about 10 degrees, which will cause gearshift problems, but will make diff choice easier.

[irish320i]

if i cant change the output flanges over i wount be able to use the e34 box cause its too big for the e30 drive shaft how much of a problem is the gear linkage if i use the e30 box what has to be done to make it fit and does it make the gear selection crap thanx for all your help lads

[Brianmoooore]

I'd be a bit concerned about the life of an E30 320 box behind a M50B25.
I've no experience of sorting the gearshift on a rotated box. Presumably the bottom link can be bent to suit, but the top link, being alloy, would present a few more problems.
There seems to be three types of drive flange you may encounter in these conversions: E30 diameter with 10mm bolts, E30 diameter with 12mm bolts, and a larger diameter with 12mm bolts.
Various props and bits of props can be used to sort this, or you can get a prop made up by a specialist for just over £100.

[DanThe]

From what ive seen the top link doesnt need bending,



But as you can see from the pic you will need to fabricate a mount as this is also rotated 10°

[irish320i]

thanx for the info making a mount up is no real problem ive acess to all i need in work as to the life of the box how bad is it likely to take the extra power if i use the zf box what shaft combo works to join it to a e30 diff

[Brianmoooore]

if i use the zf box what shaft combo works to join it to a e30 diff

I used the box from an E36 M50B20, and that mated to a standard E30 325 prop, although, from a recent thread, there is a possibility that I have 10mm bolts in 12mm holes.
E30 M3 is one thats used with one M50 box, but I'm not sure if it's the right one for you.
Note that 5th gear on a E30 box is an overdrive, while on the M50 boxs' it's direct. This means that you will need a lower ratio diff with the M50 box than the E30 one.

[irish320i]

so if i get a e36 325 box it should work ok with a e30 325 shaft once i drill the holes up to 12mm and use the larger bolts is the the e30 325 shaft shorter than the e30 320 one thank you for all this help its greatly appreciated

[Brianmoooore]

so is the the e30 325 shaft shorter than the e30 320 one

Yes

[Brianmoooore]

so if i get a e36 325 box it should work ok with a e30 325 shaft once i drill the holes up to 12mm and use the larger bolts

I've bought another M50B25 engine and box from an E36 since I did my M50 conversion, and this one has the larger flange. Came with the guibo and 200mm of the prop stilll attached, so I'll probably get a special made up.

[irish320i]

sorry to ask but is there any chance you could measure the inside diameter of the bigger drive shaft just wondering will the e30 one fit inside the larger e36 one if it did it would be a lot easier to get it welded

[Brianmoooore]

Inside diameter of the cut E36 prop is 66.2mm. Note that this is the smaller flange with 12mm bolts.
The prop I have with the large flange is 60mm OD, the same as normal E30 props.
This prop either came from an E34 M50B25 manual, or an E39 M54B25 auto.