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DISCUSSION => Engine + Driveline => Topic started by: E36-italia on October 26, 2010, 09:10:10 AM

Title: M3 3.2 6speed gearbox to an M42
Post by: E36-italia on October 26, 2010, 09:10:10 AM
I think that I have to replace my clutch in the near future (halfway the stroke it engages, but without any feel)

but the otherday i found somebody who sells rebuilded bmw engines/gearboxxes..
He also has some M3 gearboxes in stock...

The M3 3.2 6speed is, includind 1 extra gear, a fraction shorter...which should improve acceleration
here's a ratio comparison
M3:
1 - 4.23
2 - 2.51
3 - 1.67
4 - 1.23
5 - 1.00
6 - 0.83
weight = ??

here for the M42:
1 - 3.72
2 - 2.02
3 - 1.32
4 - 1.00
5 - 0.81
Weight = ??

Not totally sure about the ratios, could not find official bmw info yet..

A shorter gearbox (and with 1 gear more) would be handy, since I live at the foot of the italian alps ;-)

now i you might guess my question... would a M3 gearbox fit to an M42?
Title: M3 3.2 6speed gearbox to an M42
Post by: romkasponka on October 26, 2010, 09:58:32 AM
Good idea, except first gear ratio :). It could be that you will need shorter drive shaft.
Title: M3 3.2 6speed gearbox to an M42
Post by: fabe on October 26, 2010, 10:44:08 AM
the gearbox will fit... just that u'll need to find the right lenght of the drive shaft to mate with the longer 6 speed gearbox..
Title: M3 3.2 6speed gearbox to an M42
Post by: e30boarder on October 26, 2010, 11:49:21 AM
is there any other bmw 6 speed trannies that can bolt up to the m42? or is that the only one
Title: M3 3.2 6speed gearbox to an M42
Post by: romkasponka on October 26, 2010, 12:30:41 PM
Quote from: e30boarder;97968
is there any other bmw 6 speed trannies that can bolt up to the m42? or is that the only one


6 speed gearbox was fitted not only to m3 E36...
Title: M3 3.2 6speed gearbox to an M42
Post by: e30boarder on October 26, 2010, 02:21:00 PM
i realize that.. just wondering if there were more that could easily be adapted to work with the m42
Title: M3 3.2 6speed gearbox to an M42
Post by: fabe on October 26, 2010, 09:58:44 PM
The M42 has the same gearbox bellhousing bolt pattern with the M5x and S5x inlie 6 engines.. So it's compatible with a lot of gearboxes... only issue is sourcing the right length of the short shaft... unless you're adventurous enuf to cut and reweld the shaft to the required length..
Title: M3 3.2 6speed gearbox to an M42
Post by: E36-italia on October 27, 2010, 02:39:21 AM
Quote from: fabe;97991
The M42 has the same gearbox bellhousing bolt pattern with the M5x and S5x inlie 6 engines.. So it's compatible with a lot of gearboxes... only issue is sourcing the right length of the short shaft... unless you're adventurous enuf to cut and reweld the shaft to the required length..

judging from your words...an M3 driveshaft won't fit?
Cut&weld a driveshaft isn't really dangerous with a 140bhp engine... I don't want to do that with a 300bhp engine thou...
Title: M3 3.2 6speed gearbox to an M42
Post by: nicknikolovski on October 27, 2010, 03:53:52 AM
I'd get a custom driveshaft made up.
Title: M3 3.2 6speed gearbox to an M42
Post by: e30boarder on October 27, 2010, 10:34:16 AM
ill have to look into that. i would love to have a 6 speed in my e30
Title: M3 3.2 6speed gearbox to an M42
Post by: supadave on October 27, 2010, 01:52:50 PM
has anybody done this?
Title: M3 3.2 6speed gearbox to an M42
Post by: gearheadE30 on October 27, 2010, 06:25:46 PM
I've seen a few. Mostly using 330i E46 transmissions though, iirc
Title: M3 3.2 6speed gearbox to an M42
Post by: supadave on October 29, 2010, 07:12:51 AM
More info please! A link or something
Title: M3 3.2 6speed gearbox to an M42
Post by: fabe on October 29, 2010, 09:30:11 AM
The only thing is to source for the right length drive shaft.. Maybe the shorter shaft from the E30 M20 can be used..
Length of the shifter link and the shifter holder can be modified without much hassle.

I guess for a start, measurements of the stock G240 gearbox and driveshaft (the front portion) would be good.
Title: M3 3.2 6speed gearbox to an M42
Post by: KenC on October 29, 2010, 10:11:00 AM
What do the e46 6speeds usually go fo?

I think the 1st gear ratio would pose some problems with my 4.45LSD haha
Title: M3 3.2 6speed gearbox to an M42
Post by: E36-italia on October 29, 2010, 10:21:53 AM
Quote from: fabe;97991
unless you're adventurous enuf to cut and reweld the shaft to the required length..

Spoke to a guy who prepared a fair few WRC/group A/historic race and rally cars.. he said that cut and weld a shaft is perfectly feasable... people who build custom trucks/semi trailers are quite ok.

he did it with 3 cars, one did the london sydney marathon back in '93
and after that: cape to cape... clocked up a fair few miles... never had a problem
(Rover P5B with a 3,5L V8 ~ 250/300 BHP)
Title: M3 3.2 6speed gearbox to an M42
Post by: E36-italia on October 29, 2010, 10:24:48 AM
Quote from: KenCopperwheat;98107
What do the e46 6speeds usually go fo?

I found a E46 SMG box for 600 EUR...but it is stuck in some gear, not sure about the fix.. a sequential gearbox would be cool imo (a bit overdone in a 16year old E36)
Title: M3 3.2 6speed gearbox to an M42
Post by: fabe on October 29, 2010, 06:29:00 PM
Quote from: E36-italia;98108
Spoke to a guy who prepared a fair few WRC/group A/historic race and rally cars.. he said that cut and weld a shaft is perfectly feasable... people who build custom trucks/semi trailers are quite ok.

he did it with 3 cars, one did the london sydney marathon back in '93
and after that: cape to cape... clocked up a fair few miles... never had a problem
(Rover P5B with a 3,5L V8 ~ 250/300 BHP)


of cos it's feasible, when our stock shaft is welded together. just that u need to specialist to get it done proper with balancing. If the shaft is off balance, it's very irritating to drive.. Minor one would be slight vibration during take off.
Title: M3 3.2 6speed gearbox to an M42
Post by: nicknikolovski on October 29, 2010, 09:49:42 PM
Quote from: E36-italia;98109
I found a E46 SMG box for 600 EUR...but it is stuck in some gear, not sure about the fix.. a sequential gearbox would be cool imo (a bit overdone in a 16year old E36)


Don't get a SMG gearbox - too problematic. Trust me. and every part too expensive.
Title: M3 3.2 6speed gearbox to an M42
Post by: romkasponka on October 30, 2010, 03:37:09 AM
Better option is this http://www.samsonasmotorsport.com/index.php?-484491559 ;)

One day I will buy one for my car...
Title: M3 3.2 6speed gearbox to an M42
Post by: dvmotorsports on October 30, 2010, 03:49:34 AM
Quote from: E36-italia;98109
I found a E46 SMG box for 600 EUR...but it is stuck in some gear, not sure about the fix.. a sequential gearbox would be cool imo (a bit overdone in a 16year old E36)


When i worked for the dealer and we would get SMG trans stuck in a gear, it was always a bad SMG pump or module failure. Which results in replacement and programming of either unit.
Title: M3 3.2 6speed gearbox to an M42
Post by: supadave on November 01, 2010, 08:10:04 AM
Quote from: romkasponka;98131
Better option is this http://www.samsonasmotorsport.com/index.php?-484491559 ;)

One day I will buy one for my car...


How much?
Title: M3 3.2 6speed gearbox to an M42
Post by: ziedas nr 1 on November 01, 2010, 10:22:07 AM
araund 4000-5000 euros.
Title: M3 3.2 6speed gearbox to an M42
Post by: ziedas nr 1 on November 01, 2010, 10:31:26 AM
Quote from: E36-italia;97960
I think that I have to replace my clutch in the near future (halfway the stroke it engages, but without any feel)

but the otherday i found somebody who sells rebuilded bmw engines/gearboxxes..
He also has some M3 gearboxes in stock...

The M3 3.2 6speed is, includind 1 extra gear, a fraction shorter...which should improve acceleration
here's a ratio comparison
M3:
1 - 4.23
2 - 2.51
3 - 1.67
4 - 1.23
5 - 1.00
6 - 0.83
weight = ??

here for the M42:
1 - 3.72
2 - 2.02
3 - 1.32
4 - 1.00
5 - 0.81
Weight = ??

Not totally sure about the ratios, could not find official bmw info yet..

A shorter gearbox (and with 1 gear more) would be handy, since I live at the foot of the italian alps ;-)

now i you might guess my question... would a M3 gearbox fit to an M42?



gearbox is fit.you need to replace a driveschaft,modified a shortschift. abaut weights, a m42 gearbox weight 29kg and 400g. a m3 3,2 6speed gearbox weight 46kg.
Title: M3 3.2 6speed gearbox to an M42
Post by: supadave on November 11, 2010, 10:06:22 AM
Quote from: ziedas nr 1;98185
araund 4000-5000 euros.

WOW! Thats crazy.
Title: M3 3.2 6speed gearbox to an M42
Post by: supadave on November 11, 2010, 10:07:39 AM
I would like to see some documentation on a six speed swap.