Hi Guys

how do you tell a 7 to a 7.5"

Here's the only pic I have, I'd like to go to an LSD hence asking.

Thanks

I think that's a 7"

7.5" here http://www.turbosport.co.uk/showthread.php?113777-Granada -Cosworth-Sierra-diff-7-5-quot

the 2 side by side


[Edited on 17/10/12 by mookaloid]

thats 100% a 7inch. those mounts look a bit thin it may just be the picture but they should be 5mm thick on the roadster.

edit. btw the 7 and the 7.5 inch diff will fit on the roadster you just have unbolt and change the diff mount brackets.

[Edited on 17/10/2012 by ashg]

Hi,

I cannot tell from the picture, but as far as I know,
at the front top part of the diff where the long bolt goes is solid on the 7.5"
and open - so you can see the bolt - on the 7" diff. (see below)

HTH,

Len.

Thank you guys ill look properly tomorrow

has to be a 7" from that pic

with a 7.5" you can't fit a bolt like that

The diff in your photo has the bottom mount open along its length, you would use a long through bolt for the bottom and top mounts
You can see the long bolt through the mounting
7 1/2" diffs use2 bolts either side and the mounting points are fully enclosed for the length of the casting.

I have not seen a 7 1/2" push fit diff

[Edited on 18/10/12 by snapper]

So its a 7", Thank you guys..

My next question now you have all helped it, is there any point and can I, change to a 7.5" ?

PS. On the look out for a 7" with LSD

^^ I take it your thinking about a cossie 7.5" LSD ?

for either a 7" or a 7.5" you'll need different driveshafts to use the std. ford LSD's as these only come in bolt-on vesions and can't be changed to push-in

you can make up hybrid shafts (push-in at the wheel end and bolt-on at the diff end)

or you can swap the shafts and hubs to bolt-on (this means you'll probably end up with rear discs too, at least without alot of messing about)


but the bolt-on setup used on the RWD sierra cossie is a size bigger than the rest of them (108mm flanges instead of 100mm) so you can't make hybrid shafts for these and they need the matching hubs too (bigger bearings, bigger discs, bigger everything...)





you could fit a quaife or tranx aftermarket LSD to your current diff without changing anything else
here's how:
http://www.locostbuilders.co.uk/viewthread.php?tid=138216

[Edited on 18/10/2012 by mcerd1]

Im a bit confused,

cant I just change the diff for another 7" with LSD?

[Edited on 18/10/12 by YODI]

not if its a ford LSD - your 'push-in' type driveshafts won't fit them

[Edited on 18/10/2012 by mcerd1]

Ah ok, so I needed that set up that was for sale on here last week with the drive shafts, hubs etc

Do you have rear disk or drum brakes?

Drums, which I obviously dont want either

nowt wrong with drums on these cars apart from the looks
(if you'd had discs at the moment they would have had to be on adapters - ford didn't make any cars with rear discs and push-in shafts, nor any with drums and bolt-on shafts)


to make up hybrid shafts you'd need to check the size of the push-in shafts you've got now, if they are the right ones you can dismantle the inner CV's and swap them for the bolt-on type ones (its been done by a few folk here, do a search for hybrid shafts in the old posts)

otherwise the options are to swap the whole rear axle or fit an aftermarket LSD

[Edited on 18/10/2012 by mcerd1]

Thanks mate ill look into it