diff differences same model

[gareth12]

Hey, picked up a GH diff today for my GJ wagon... I noticed at the wrecker there was two different diffs in the early type, one had a bolt out centre, one had a back plate and internal centre... I noticed the top centre arms were different. Im guessing that they are interchangeable as long as you swap the top arms aswell?

I only got the diff for the mountings, so dont care about strength of the diffs, but is one mounting setup any better than another?

[A112H]

MMMM, I could be completely wrong but I understand that all but the very early diffs were bolt out centre. GC/D, GTO and FTO used the same bolt out centre but are not interchangeable with the Sigma/Scorpion centres.
GE Scorpion, JA Starion and Sigma being 8 bolt and GH and newer Scorpion, JB/D Starion and EX Lancer being 10 bolt?
The GH has a different hand brake cable to the later models and there is some difference in the locating arms and brakes but the housings are the same.
As always, I am happy to be enlightened if I am wrong or missed something

[Scorpma82]

possible diff conversion?????

[woops]

What you are describing is probably a GH scorpion and a GH sigma diff. The scorpion have the same mounting positions but the the bushes are on the upper control arms instead of on the diff. Also the sigma has the borg warner with the 8 bolt flange on the back and the scorpion have the stronger jap diff with the diff completely removal. There is also the 8bolt scorpion diff which was on the GE scorpion i think and the 10 bolt on the gh ones. Also the GJ scorpions were still a jap diff but will only suit the sedans. The wagon's used the GE/GH style mountings from the start and continued to the GN model. Whereas teh sedans changed the control arm positions between the GH and GJ sigma/scorpion.

So basically if the diff is a 10 bolt scorpion and you can also get the upper control arms it is a decent upgrade. You can also bolt starion rear brakes onto that diff to get vented rear disc's too.

[A112H]

Thanks woops, never really played with Sigmas so I was guessing they had the 8 bolt never knew they ran a BW diff.
See, this is how we learn

[Scorpma82]

yeah alot of the later model sigma ran BW's.....but seriously???????

Ud break them just by looking at them

[A112H]

I am guessing then that it isn't the same BW as used by XE-AU Falcon, VB-VR Commodore and R31 Skyline?
If it was they would be hot property considering the massive range of ratios and LS centres that would be available.

[cheaterparts]

I am guessing then that it isn't the same BW as used by XE-AU Falcon, VB-VR Commodore and R31 Skyline?
If it was they would be hot property considering the massive range of ratios and LS centres that would be available.

the sigma ran a smaller BW diff than the Commodare/falcon - and yes they break if treated poorly ( I know that for a fact )
the early scorp had the 8 bolt and of cause the later a 10 bolt bango diff ( which I found could also be broken )

I ended up using a Datson H190 diff that they used in the utes and Bluebirds but had planed to use a larger BW diff , the same as the commodre/falcon
easier to get , plenty of ratios and ether LSD or spools again are easy to get best of all 28 spline axles

[A112H]

Well I hope mine holds out cheater, i have just fitted a Scorpion 10 bolt with LS centre to the GC

[gareth12]

I have an 82 2WD hilux diff and a 3.58 LSD centre sitting on my garage floor, i got the housing just to make a jig and cut the mounts off.

It was in a sigma but could well have been a scorprion diff, had no brakes on it. There was another scorpion there with the same setup

The scorion setup looks slightly easier to replicate as its just the plate bracket on the diff rather than the sigma way

Looks like im onto a winnner!

[Scorpma82]

The R31 Skylines (and i believe Pintara's) ran a BW which also run an LSD and a series of different ratios (although their are a few differences such as splines and general strength)

[A112H]

They ran the same centre as the Falcon and Commodore of the time but Pintara ran 25 spline and the Skyline ran 28 spline.
As cheater said, the beauty of the Skyline diff for us is the disc brakes but the centres are a direct swap for the Ford and GMH centres so you can get anything from 2.78 in the Fairmont to I think 4.66 in the RTV AU utes. All available in LS option

[Scorpma82]

yeah, i'm going 3.08 in my next wagon....not looking for speed...just want a car thats comfortable and capable of being at 60mph for a few hours without wearing out the engine from excessive rpm

[gareth12]

with the skyline you could get away without narrowing it with the right offset wheel

only reason i went the hilux was the 5 stud wheel choice and a removable centre which is about the only place the BW falls down

[A112H]

True Gareth, that's why I went LSD Scorpion housing. Got the 3.3 ratio I wanted and didn't need to narrow it under the hardtop. Even my 7.5's +0 just tuck in

[davetrees]

Well I hope mine holds out cheater, i have just fitted a Scorpion 10 bolt with LS centre to the GC

Like any diff, it will only break if you abuse it

[A112H]

This is true. I didn't break the stock Galant diff so I think the LS 10 bolt should be fine

[cheaterparts]

Like any diff, it will only break if you abuse it

correct - my diffs had to stand a fair amount of abuse ,a lot more than a street car would on average
in fact I dout if any of my breakages would happen on the street or on a circuit , Hillclimb was quite hard on running gear
ie - pick a warm day whith a lot of cars laying down rubber on the start line and first section of track , using sticky tyres
then using well practiced starts and power changing at 7000 +

I have also snaped an output shaft on a Jap 5 speed which is something that most havent

I dont know if you ever played at Morwell hillclimb Dave but I got down to a 35.87 sec run with the sigma in full IPRV trim

[BAD-SIG]

The very early model GE Sigma sedans also had the 8 bolt banjo-type japanese diff, same as the early GE Scorpions and Galants. Mine has one

[gareth12]

anyone ever bent a top centre arm on the early/scorpion type? They look pretty flimsy compared to the later ones, and i will have a bit of power/torque