e30 m40 propshaft to e30 m20 with g240 gear box

[markus_74]

hello,

my car is e30 with m40 engine. it is difficult here to find proper m20 propshaft and medium case diff so I will use my old propshaft and small case diff 4.10 for a while before I can upgrade to medium case diff 3.64.

so I have now g240 gearbox and small case diff 4.10

need some info how to cut the propshaft?

which part should I cut? the front propshaft only? or including the rear that attach to the differential? may

and if next time I upgrade my small case diff with medium case diff, should I cut again the rear part of my propshaft to adjust with new diff?

may be someone has info on the dimension of the front propshaft and rear propshat, so I can copy it?

thank you
markus

[age]

i have a similar problem at the moment,

i'm not a fan of a cut and shut prop, thats kind of a specialist ob as it needs to be balanced.

my solution is to fit the m4x gearbox and make some custom gear linkages similar to using an m20 box on an m52 except the box will sit at the opposite angle

[Brianmoooore]

Rear half of prop. is already adjustable for length, is the same length for all engine sizes, and fits both small and medium cased diffs.
The front section is the bit that varies, and if you resort to cutting and welding, will need to be balanced.
A DIY method of this is to fit two jubilee clips to the shaft. With the worm drive mechanisms opposite each other they will have no effect, with the two mechanisms beside each other they will have maximum effect, and of course will need to be rotated around the shaft to find the best balance by experiment.

[markus_74]

I just search in the wikizone about propshaft but I surprise with the result

manual propshaft:
316i 318i (M40) 1480mm
320i 1526mm

does the size is correct because I think 320i has shorter propshaft than 318i m40, because the m20 engine is longer and sit backward than m40?

please correct me if I'm wrong,

I'm looking the front of proshaft size so I can cut and welding it