Help with gearbox conversion for m20

[kipsy]

Hello, I'm mid way through fitting a 318is e36 box to my m20 325. Before I offered them up I noticed that the input shafts are different sizes. There appears to be a sleeve in the end of the crank that is currently 12mm where the new box needs 15mm. Anyone got any ideas? Ta

E36 input shaft

[e30-EVN]

yes, go to bmw and purchase a 15mm spigot bearing for the new box. prob cost you around the 12 quid mark...

use a bearing puller to remove the m20 spigott from the crank and fit the 15mm e36 item. job done

[kipsy]

Fantastic. Thanks very much

[e21Jason]

How you sorting the difference in mounting angle for the gear lever

[kipsy]

Not yet will cross that road when I get there. I got two linkages to make one out of the two and access to a tig in work

[Jhonno]

Why are you fitting an M42 box to an M20?

[kipsy]

Because it's a direct 5th gear and so the ratios will be closer together. 1st will be pretty useless But better everywhere else. 103 moh at 6500 rpm

[Grrrmachine]

So you just want outright acceleration rather than any sort of top speed?

You could have saved yourself a lot of time and trouble by just fitting the gearbox off a normal 320.

[kipsy]

That's what I'm replacing now- overdrive 5th on that one-125mph top speed

[mrLEE30]

Or saved a load more time a money and fit a 4.5 diff.

[kipsy]

4.45 diff already fitted fella

[kevo]

touche ha ha

[mrLEE30]

Ok fit smaller wheels!!!

If you dont mind, what the hell do you plan on doing with it? Hill climbs?

[e21Jason]

When I got my m3 it had a 4.45 lsd rebuilt to with extra clutch plates and dogleg box it was pretty quick of the mark and used 4/5 mostly aroudn the track and 2n ran by the end of the pit lane, but it was a gravel spec rally car.

[kipsy]

I've been running 14s and 15s, will be only using 15s once used up my 14inch Tyres. The car is used for rallying. It will do 103 on 15 inch Tyres at 6500 in 5th once box changed. When I put my m52 28 in I'll hopefully find a 4.1 so will do 112 ish then which is fine. All about acceleration
This is the basic stuff I'll be doing. Great fun

[Andyboy]

Not sure the Getrag 250 will last long - really, you need a 310 328i type box.

[kipsy]

I heard the 318is e36 box was the best cheap option. I know someone who runs an m3 motor through one in a compact bm unless I've made a mistake?

[kipsy]

Spigot bearing now changed. Guessed the clutch alignment with some ally bar but will have to make a better version as box awkward to get in. I've now got to enlarge the 10mm holes in the rubber propshaft damper to 12 mm as e36 uses larger bolts. Turning into a bit more work than expected