My 1988 LFX F40 build. (Page 57/68)
msweldon OCT 30, 06:23 PM

quote
Originally posted by fieroguru:

The Cobalt axle issue is due to old info and GM changing the differential offset with the production run of the F40.

People have used the Cobalt axles with the G6 version of the F40 by moving the drivetrain towards the passenger side. You guys are not using that version of the F40.

The issue is at sometime during the production run (2009 or possibly later) GM made the bellhousing on the non-GM metric versions deeper so they could fit larger clutch setups for higher HP and AWD applications. This moved the differential about 1" further from the engine vs. the G6 F40.



Hmmm.. I was able to mount my LF3 with the 2008 Saab 9-3 F40 which had been in production since 2006. I don't have a G6/F40 to compare it to but I was able to square up the LF3/F40 combo on the cradle with the cobalt turbo axles resting 50% in the tripot housings in the F40. This was all accomplished by moving the block/tranny mating point/line approximately two inches toward the passenger side.

Here's the driver side but did the same thing with the PS to make sure everything squared up.
fieroguru OCT 30, 06:58 PM

quote
Originally posted by Rickady88GT:
A good clutch can fit in the short bell housing right? GM used a dual mass system that took up some space.



Compared to the Getrag or F23, even the shallow G6 F40 bellhousing is cavernous. I fit a 10" clutch in mine and Mwhite used a twin disk clutch in his.


quote
Originally posted by msweldon:
Hmmm.. I was able to mount my LF3 with the 2008 Saab 9-3 F40 which had been in production since 2006. I don't have a G6/F40 to compare it to but I was able to square up the LF3/F40 combo on the cradle with the cobalt turbo axles resting 50% in the tripot housings in the F40. This was all accomplished by moving the block/tranny mating point/line approximately two inches toward the passenger side.



Looks like they phased in the bellhousings starting in 2008/2009. I also found a reference for both depths in 2011-2014.


quote

2009 F40 (MK6)
General Motors Powertrain-Europe F40 six-speed manual car transaxle
2009 Model Year Summary

Carryover Features and Benefits from 2008i model year

ALL WHEEL DRIVE ADOPTION
The transmission housings are reinforced and elongated for bigger clutch size, 250 mm. The differential is upgraded concerning size and material in order to withstand higher output torque for AWD system.
Daryl M OCT 30, 07:46 PM

quote
Originally posted by fieroguru:

The Cobalt axle issue is due to old info and GM changing the differential offset with the production run of the F40.

People have used the Cobalt axles with the G6 version of the F40 by moving the drivetrain towards the passenger side. You guys are not using that version of the F40.

The issue is at sometime during the production run (2009 or possibly later) GM made the bellhousing on the non-GM metric versions deeper so they could fit larger clutch setups for higher HP and AWD applications. This moved the differential about 1" further from the engine vs. the G6 F40.

Here are a couple of picture of the G6 version (clean) and a later model version.




Guru, thanks for that info. I don't think I will have an issue with axle length. When I designed my engine/transmission mounts, I had the suspension and axles in place and centered the assembly so the whole thing was equal on both sides. I won't comment on axle strength, because I have no experience with them, but I do not intend on abusing the axles with the way I drive.
msweldon OCT 31, 11:30 AM
[QUOTE]Originally posted by fieroguru:


Compared to the Getrag or F23, even the shallow G6 F40 bellhousing is cavernous. I fit a 10" clutch in mine and Mwhite used a twin disk clutch in his.
[QUOTE]

Could you elaborate on this twin disc setup he used? I tried to get RAM clutch to design and implement a 9.5" one for the f40 with everything a go except the input shaft out of the F40 was an inch too short..
fieroguru OCT 31, 12:53 PM

quote
Originally posted by msweldon:
Could you elaborate on this twin disc setup he used? I tried to get RAM clutch to design and implement a 9.5" one for the f40 with everything a go except the input shaft out of the F40 was an inch too short..



http://www.fiero.nl/forum/A...160323-2-123953.html
Will NOV 01, 09:30 AM

quote
Originally posted by fieroguru:

The Cobalt axle issue is due to old info and GM changing the differential offset with the production run of the F40.

People have used the Cobalt axles with the G6 version of the F40 by moving the drivetrain towards the passenger side. You guys are not using that version of the F40.

The issue is at sometime during the production run (2009 or possibly later) GM made the bellhousing on the non-GM metric versions deeper so they could fit larger clutch setups for higher HP and AWD applications. This moved the differential about 1" further from the engine vs. the G6 F40.

Here are a couple of picture of the G6 version (clean) and a later model version.
http://fieroguruperformance...6-e1503262979609.jpg
]http://fieroguruperformance...62967347.jpg


They may even have done something similar with the F23, as the (later) Ecotec bellhousing is 10mm deeper than the (earlier) metric (2.2 pushrod) bellhousing.

[This message has been edited by Will (edited 11-01-2020).]

Daryl M NOV 01, 03:56 PM

quote
Originally posted by msweldon:


Hmmm.. I was able to mount my LF3 with the 2008 Saab 9-3 F40 which had been in production since 2006. I don't have a G6/F40 to compare it to but I was able to square up the LF3/F40 combo on the cradle with the cobalt turbo axles resting 50% in the tripot housings in the F40. This was all accomplished by moving the block/tranny mating point/line approximately two inches toward the passenger side.

Here's the driver side but did the same thing with the PS to make sure everything squared up.





Looks very similar to my result.
Daryl M NOV 17, 03:56 PM


On the left is the plastic hydrolic fitting for the clutch slave and associated items that I could not get to stop leaking.
On the right is my fabricated apparatus to serve the same function.
Comments encouraged.
Thanks
Daryl
Will NOV 17, 05:18 PM
Complete with clutch isolation valve because you removed neutral from the transmission to save weight?
Daryl M NOV 17, 05:44 PM
My attempt at a bleed valve.