just wondering will a scorpio diff fit my sierra ...as I want to put an LSD into it and I cant find any here in Ireland and I kno where there is a scorpio that may have an LSD

 

You'd need the rear suspension from a 2wd cosworth, as scorpio diff is 7.5".
Normal Sierra diff apart from 2wd cossie is 7", so scorpio diff won't fit in the sierra rear subframe.
Also, Scorpio diffs have flanges for driveshaft attachment, but only Sierra's with 4x4 or ABS have flanges, all others the driveshafts just slide into the differential.
Then you'd also need a bigger master cylinder(or brake booster from ABS equipped Sierra/Scorpio), as the small cylinder is only suited for disc/drum set-up.

So...it will fit, but it's not exactly simple.
If your car has ABS though, any differential from a 4x4 Sierra fits bolt-on, and at least over here all 4x4 Sierra's had a rear LSD.

 

mine isn't 4x4 its just a 2.0

 

And no ABS?

 

nope no abs

 

I believe you can also fit the bolt on CV joints from the Scorpio diff to the Sierra driveshafts. But make sure the diff is from a Scorpio/Granada mk3, and not the later 95-98 bugeye Scorpio, as those diffs won't fit.

 

questions

does your current car have rear discs?

is the car you are removing it from the granada scorpio or the bug eye'd scorpio scorpio?

if the answer to both is "yes" then it will fit

if not then it won't

if it doesn't fit into the diff casing then you only need to chop a bit of the casing off where the bolt goes through, doesn't affect the strength, just different fitments

 

no it has drums and yes the scorpio is the round type headlights

 

fail on both types then really as it's not easy to swap without having the whole rear beam from the lsd version, plus you'll need the upgraded master cylinder and servo as well as the matching front brakes

if you have the car as a donor you could at least rip most of the bits out that you may need in the swap but be aware that the car might have had traction control instead which was operated via the brakes and not an lsd as they were either/or

 

I didn't know any bug eye scorpio had LSD, only traction control system.

Scratch that plan mate...

Over here in the 80's Ford of Finland offered a ZF limited slip diff, this was installed in the regular 7" slot-in differential, and that's pure bolt-on. Don't know if they offered such over there though, so it might be there are no bolt-on options for your Sierra, and the only reasonable way to get a limited-slip-diff is to buy one that fits in the casing. Quaife does one, costs about a grand...
I don't think ZF makes them any more, which is a shame, as they're next to impossible to find these days, and it made for an excellent car. Better than Ford's own viscous unit in my opinion.