911SC shortbell g50 conversion questions.

[Madsimilius]

I have a G50/00 transmission that me and my cousin shortened, and now i just want to make sure i'm doing everything right.
I'm using a Ruf preasure plate and sachs performance disc

1. Other then shortening the bellhousing and the axle, is there anything else on the transmission that needs machining?

2. I've seen that i could buy a modified guidetube for g50 short bellhousing.
Do i need to modify mine? Shorten it? how much?

3. Since the engine needs to go back a little. do i need to modify the engine mount cross bar? if so any good solutions?

I've also read somewhere that the i don't need to move the engine back in a 911sc with a short bellhousing g50/00 and g50/01 is this right ? from my measurments comparing to the 915 it seems like i must move it 1-1.5cm back 2/5"-3/5"


Other usefull info is of course also very welcome.

[spuggy]

Originally Posted by Madsimilius

I have a G50/00 transmission that me and my cousin shortened, and now i just want to make sure i'm doing everything right.
I'm using a Ruf preasure plate and sachs performance disc

Err, why? That'd hold EFI 930 torque.

Originally Posted by Madsimilius

1. Other then shortening the bellhousing and the axle, is there anything else on the transmission that needs machining?
2. I've seen that i could buy a modified guidetube for g50 short bellhousing.
Do i need to modify mine? Shorten it? how much?

Been a while, but I believe the guidetube is just shortened a little - seem to recall 3-5mm - to prevent fouling the clutch release forks? Something to do with everything having less clearance/being different angles with the early 930-style clutch pack.

Originally Posted by Madsimilius

3. Since the engine needs to go back a little. do i need to modify the engine mount cross bar? if so any good solutions?

Engine mount is springy in that plane and accepts tension/bends quite readily; probably the least of your problems

The Patrick Motorsports transmission cross bar is a nice piece; slotted for adjustment and accepts 915-style transmission mounts (e.g. WEVO).

Originally Posted by Madsimilius

I've also read somewhere that the i don't need to move the engine back in a 911sc with a short bellhousing g50/00 and g50/01 is this right ? from my measurments comparing to the 915 it seems like i must move it 1-1.5cm back 2/5"-3/5"

Uh. Shop that did mine had done short bell G50 conversions on both earlier (74) and later (SC) cars than mine and had never had to modify the torsion bar piece. Until they did my car. Which basically already had little clearance between the rear cross-member and the engine pulley with a 915.

Torsion bar cover had to be cut away for the extra clearance to even get the motor/transmission back in the car, never mind moving the motor back. Number of people doing the conversion have found the same thing; there really doesn't seem to be any way to tell.

It seems odd, because they're all supposed to be the same, but there you go...

Originally Posted by Madsimilius

Other usefull info is of course also very welcome.

Throw away the stock junk and replace with a J West shifter and G50 coupler. You'll love them - once you re-program yourself to stop getting 5th when you thought you were selecting 3rd, if you're used to a 915...

Good luck!

[ALEX P]

Have a good read of this, it will probably answer quite a lot:

915 to G50 conversion on '85 911 - What's needed guide‏

[Madsimilius]

Spuggy, was your transmission a later model g50 transmission? from what i've read the differential in the 89 turbo g50 and newer g50's is bigger which makes the transmission except from the nose, 2.3cm or so longer then the first 3.2 carrera g50 transmissions.
Eer why what? why i'm using the ruf pressure plate?

Thank you both for the help.

[spuggy]

Originally Posted by Madsimilius

Spuggy, was your transmission a later model g50 transmission?

No, it was a G50/00 from a 86-89 Targa that got lunched at a red light with around 100K street miles.

(Some people hate Targas; I think they make great parts cars )

Just as a datapoint for those that think G50's don't wear out with a 3.2, bill for wear parts and rebuild (shift forks, synchros, bearings, seals etc) was probably about the same cost as the used box. Not figuring machining for modifications, upgrade bits or fitting same.

Originally Posted by Madsimilius

from what i've read the differential in the 89 turbo g50 and newer g50's is bigger which makes the transmission except from the nose, 2.3cm or so longer then the first 3.2 carrera g50 transmissions.

I found out that /03 and up were stronger. After I'd already sourced a /00 and shipped it off for machining. So I forgot about it

If that makes the transmission longer, it would have been a problem for me anyway; there's no room for a longer transmission in my car without removing the torsions altogether.

930/60 was already a tight fit with a 915, with a shortened G50/00, there's just no extra room fore/aft.

Originally Posted by Madsimilius

Eer why what? why i'm using the ruf pressure plate?

Yes - I expect my HD stage 1 pressure plate/stock friction plate to hold 550 ft/lbs, and I'll be unhappy if I have to downgrade the MoTeC tune until I can be bothered to upgrade to a more studly clutch..

So I'm curious what motor you're planning on putting behind that clutch

If you're making significantly more power than a stock 930, billet side-cover and LSD are probably a good investment as well. Otherwise, a stock clutch should be well up to it.

Apparently, /00 cast side covers aren't the strongest.

Originally Posted by Madsimilius

Thank you both for the help.

Good luck with the conversion. Take lots of photos !!

[aston@ultrasw.c]

When installing a shortened G50 into may 86, I was forced to remove some of the torsion bar housing. Not my best work....



Yeah I know - anyway learn from my mistake.

It may have been OK for a street car but under the pounding it took on the track it failed.

The inner T bar receiver (that is that part called?) rotated in the tube allowing the rear ride height to evaporate.

I was forced to abandon the T bars, remove more material, weld the internals and then plate over the opening.

[aston@ultrasw.c]

To salvage my shattered reputation, here's my alternative to simply bending the engine cross member.

[Madsimilius]

Nice jobb with the engine cross member and console !
I have the patrick motorsport side plate , and im thinking of buying a gripper or guard lsd.
My engine is a sc engine with 3.3 pistons and cylinders which makes it a 3.12 liter
Patrick motorsport RSR flywheel.
Arp rod and head bolts.
Race valvesprings and titanium retainers.
40mm ported heads.
stock sc cams.
Full exhaust with kkk k27/k29 turbo with a 1.2 bar WG spring.
3.2 intake manifold with 75 lb/hr injectors and msx3 efi and ignition.