M42club.com - Home of the BMW E30/E36 318i/iS

DISCUSSION => Engine + Driveline => Topic started by: visionracingdevelopments on September 09, 2009, 01:24:50 PM

Title: M42 engine and M40 gearbox combo
Post by: visionracingdevelopments on September 09, 2009, 01:24:50 PM

Any one done it? or am I the only one?

No one seems to be able to tell me which prop I can use and I have a car sat on stands doing feck all which is driving me mad!

The iS prop is 35mm too short and it cannot be adjusted on the gearbox side, the M40 prop is evenr shorter!

I really need this info FAST if any one can help!!!

Title: M42 engine and M40 gearbox combo
Post by: fabe on September 09, 2009, 03:30:01 PM

My E30 was running the E36M42 with the E30M40 getrag240, no issue whatsoever. Nothing along the drivetrain was changed

What seem to be your issues? Can't help u with a very vague description of your problems.

Title: M42 engine and M40 gearbox combo
Post by: visionracingdevelopments on September 09, 2009, 04:02:32 PM

My applogies but how much can I write on the matter to make it not vague? My M42 iS prop shaft is 35mm too short and I need a solution.

Title: M42 engine and M40 gearbox combo
Post by: fabe on September 09, 2009, 10:31:08 PM

The M42 engine block mounts at the same position as the M40. So everything after the engine to the rear diff shouldn't have changed..

Maybe you should state what was the base car, what has been done so far..

Title: M42 engine and M40 gearbox combo
Post by: Boyracer on September 10, 2009, 03:36:06 AM

In E36 M42 and M40 (and M43 and N42 etc etc etc...) share the same gearbox, they are identical.

Not sure about E30 but I suspect it is the same.

Title: M42 engine and M40 gearbox combo
Post by: visionracingdevelopments on September 11, 2009, 05:34:56 AM

Quote from: fabe;78184

The M42 engine block mounts at the same position as the M40. So everything after the engine to the rear diff shouldn't have changed..

The output flange of the M40 gearbox is 35mm closer to the casing of the box than the M42 box is hence why my 318iS prop is too short because the flange is 35mm further away.

It's a E30 318iS, with an E30 M42 fitted, with an E30 M40 gearbox. It did have an E30 318iS gearbox with the flange further away but it didn't select first so I changed it for the E30 M40 one.

Title: M42 engine and M40 gearbox combo
Post by: fabe on September 11, 2009, 05:48:10 AM

hmmm. i always thot the E30 M40 and M42 shares the same Getrag 240.... any photo?

Title: M42 engine and M40 gearbox combo
Post by: visionracingdevelopments on September 11, 2009, 06:45:24 AM

Checked the tags both at 240 Getrag gearboxes.

Here is the back of the 'M42' box:

(http://i296.photobucket.com/albums/mm184/rix313/IMG_5303.jpg)


Here is the back of the 'M40' box:

(http://i296.photobucket.com/albums/mm184/rix313/IMG_5306.jpg)


Also took a pic of the props. The lower one is the 318iS one which although longer, is still 35mm too short and the top one is a 318i one which is even shorter:

(http://i296.photobucket.com/albums/mm184/rix313/IMG_5313.jpg)

Title: M42 engine and M40 gearbox combo
Post by: dsm2002 on September 11, 2009, 07:03:57 AM

For some reason the air conditioned and non-air conditioned 318iS use different gearboxes - see link (http://bmwfans.info/parts/catalog/E30/2-doors/Europe/318is-M42/RHD/M/1989/august/browse/manual_transmission/manual_gearbox/)

Also there seems to be a difference in the tailshafts between the m40 and m42 powered cars.

318i M40 tailshaft (http://bmwfans.info/parts/catalog/E30/2-doors/Europe/318i-M40/RHD/M/1989/august/browse/drive_shaft/drive_shaft_constant_velocity_joint/)

318is M42 tailshaft (http://bmwfans.info/parts/catalog/E30/2-doors/Europe/318is-M42/RHD/M/1989/august/browse/drive_shaft/drive_shaft_swivel_joint/)

I am guessing you need an m40 tailshaft.


Edit: as I took a long to type this up, I missed the pics. Can you swap over the flanges.