Is it a 7" or 7.5" differential???
Is it a 7" or 7.5" differential???
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Discussion

techbotics

Original Poster:

1,805 posts

211 months

Tuesday 3rd January 2012
quotequote all
Hello There..

Apologies I cannpt remember if the diff I took off my S was a 7" or 7.5" whats its size and origin please...

BTW I have a 7.5" on there now... but as said can't remember what the standard size is.

Thanks

Damian S3

phillpot

17,510 posts

212 months

Tuesday 3rd January 2012
quotequote all
techbotics said:
but as said can't remember what the standard size is.
7 & half inch with 100mm flanges I believe.

7 inch has a slightly different mounting arrangement,a clearance hole right through the top mounting rather than threads each side.

Edited by phillpot on Tuesday 3rd January 18:08

ketvrin

3,504 posts

238 months

Tuesday 3rd January 2012
quotequote all
I was just going to post this one on ebay as a cheap diff (not LSD) for someone... its not yours is it ?

http://www.ebay.co.uk/itm/FORD-SIERRA-GRANADA-7-5-...

its the correct ratio, is 7.5 inch with the correct 100mm flanges

nothing to do with me...

Also see here in the FAQ's

http://www.pistonheads.co.uk/gassing/topic.asp?h=0...

HTH

K wink

Edited by ketvrin on Tuesday 3rd January 19:43

ketvrin

3,504 posts

238 months

Tuesday 3rd January 2012
quotequote all
this one IS LSD but look at the price...

http://www.ebay.co.uk/itm/GRANADA-COSWORTH-LIMITED...

K frown

Jed-S

660 posts

245 months

Tuesday 3rd January 2012
quotequote all
ketvrin said:
this one IS LSD but look at the price...

http://www.ebay.co.uk/itm/GRANADA-COSWORTH-LIMITED...

K frown
Yikes - and they even say that the teeth are worn/pitted. I think I'll save my spare one for my retirement fund.

J

phillpot

17,510 posts

212 months

Tuesday 3rd January 2012
quotequote all
ketvrin said:
I was just going to post this one on ebay as a cheap diff
Nice picture of a tape measure but doesn't the 7.5" refer to the crown wheel diameter?

Love the description of the worn gears on the LSD (thought around a £100 was the going rate), shouldn't someone involved in cars know they are called planet and sun gears !

jwoffshore

461 posts

283 months

Tuesday 3rd January 2012
quotequote all
phillpot said:
Nice picture of a tape measure but doesn't the 7.5" refer to the crown wheel diameter?
It does refer to the crown wheel, but by happy coincidence the measurement across the mounting lugs is about the same and an easy way to tell them apart. I think there were also 6.5" diffs on the 4 cylinder Sierras, then 7" on the V6 ones, 7.5" on the 2WD Cosworths, back to 7" on the 4WD Cosworths. Not forgetting the various output flange permutations!

ketvrin

3,504 posts

238 months

Tuesday 3rd January 2012
quotequote all
I was looking to find out the going rate as I have an LSD to sell. It has 108mm flanges rolleyes so is no good for an S (unless you've beefed up the drive shafts on yours)

I reckon good diffs are going to get harder to find...

K wink

Barkychoc

7,848 posts

233 months

Tuesday 3rd January 2012
quotequote all
ketvrin said:
I was looking to find out the going rate as I have an LSD to sell. It has 108mm flanges rolleyes so is no good for an S (unless you've beefed up the drive shafts on yours)

I reckon good diffs are going to get harder to find...

K wink
Has anyone looked into a 108mm CV joint fitting onto an existing S driveshaft?
It probably won't fit but you never know.

ketvrin

3,504 posts

238 months

Tuesday 3rd January 2012
quotequote all
Barkychoc said:
Has anyone looked into a 108mm CV joint fitting onto an existing S driveshaft?
It probably won't fit but you never know.
I looked at swapping the stub-shafts but they are different lengths to start with... I think the flanges are stepped to assist location (could be wrong as its a couple of years since I was looking at these) so I abandoned the idea could use one of these ? scratchchin

K wink

jwoffshore

461 posts

283 months

Tuesday 3rd January 2012
quotequote all
I haven't tried it, but probably you can swap the flanges from one diff to another, if you are prepared to strip it apart. The drive shafts are bigger for the 108mm joints, but you could get custom shafts made to take 100mm and 108mm joint at either end.

I did look at fitting the stub axles with 108mm flanges to the suspension arms, but there is not enough clearance. You would need to modify (cut & weld) the suspension arm.

The Cosworth Sierra people sometimes fit a Jag diff, but I have no idea if it would fit the S.

techbotics

Original Poster:

1,805 posts

211 months

Tuesday 3rd January 2012
quotequote all
Thanks for the replies my eBay cos LSD is whining like a mother hubbard so will get a quaife put in my origional unit. Any reccomendations in yorkshire.?

In my cossie days a saw a 9" big tooth on a bench at turbosystems awsome looked like a truck part, it was going in a 500+ bhp 3 door I think.

Cheers D S3

techbotics

Original Poster:

1,805 posts

211 months

Tuesday 3rd January 2012
quotequote all
Doh double post damn fruit phone

Cheers D S3

jwoffshore

461 posts

283 months

Tuesday 3rd January 2012
quotequote all
I'm pretty sure you could mix & match to fit the Cossie LSD with the crown wheel & pinion from your original open diff (assuming you still have it). I have not used them personally, but www.gearboxman.co.uk seem to get positive mentions. They can overhaul/uprate the viscous LSD part for you as well.

techbotics

Original Poster:

1,805 posts

211 months

Tuesday 3rd January 2012
quotequote all
Ooo I like your thinking.. Options... Hmm

GreenV8S

31,017 posts

313 months

Wednesday 4th January 2012
quotequote all
jwoffshore said:
The drive shafts are bigger for the 108mm joints, but you could get custom shafts made to take 100mm and 108mm joint at either end.
That's what I do on mine. The smaller joint remains the weakest point, of course.

ketvrin

3,504 posts

238 months

Thursday 5th January 2012
quotequote all
So there might be a market on here for my 7.5 inch 3.64:1 LSD with 108mm flanges after all ?

pm me if you are interested... I am not after big money...

K wink

techbotics

Original Poster:

1,805 posts

211 months

Thursday 5th January 2012
quotequote all
Sending my old unit to Quaife for ATB rebuild, it's gonna be a couple of weeks.. Can't wait.

Damian S3