MadaboutKitcars

If anyone has, or sees, a Ford Ultima (the last of the Frogeye Scorpios) 2.5 Diesel 3.36 rear diff for sale, I would be pleased to hear from anyone with news.

Mike

Wow, that sounds rare and expensive

Maybe try posting a request on here....?

http://www.fordscorpio.co.uk/cgi-bin/yabb/YaBB.pl

Good luck!

There's a couple of frogs being broken on eBay at the moment - maybe a call to see if they have nothing that's suits?

I know you want it for the different mounting method (koala 'ears') - is there no way you cold modify your existing diff to achieve the same thing?

Hi Mike. I have sent you a PM query about diffs. Peter.

I think a bar with two eyes welded at the outer ends bolted too the diff where the current bush mounts would work.

Pop a couple of readily available bushes in the eyes (size them appropriately for the bushes you want to use - you could always get the koala bushes from ford), and then fabricate new mounting points on the chassis.

Got to be cheaper and easier to find than the replacement diff?

Here's my idea:

Hi GOO

That is a possibility which I have given little thought to, but may prove the least frustrating option. I would have to make my own robust bracket to fit the rear of my standard diff, creating the 'koala' style double fixing: and a second to fix to the chassis.

Edit: exactly as per your very good sketch which I've now just seen - what software are you using to create drawings as good as that?

Its interesting for me to see that you guys have this type of arrangement as standard on the BMW - well you would expect nothing less from BMW would you!?!.

An Ultima diff does have other significant benefits though: it is more robust - the bearings and the crown wheel and pinions are bigger, and also it has a standard LSD. So, all gain - no pain - except I the frustration, and delay in looking for (and never finding?) one.

So, your suggestion probably becomes the easiest option to make happen. It is not a big hardship, as I beleive the standard Sierra diff is OK to 350+HP. And having built my own car, and seen the diff move around when the clutch is let out normally (my chassis stands are very robust, and very useful for checking this type of issue) I am very wary of what racing starts will do!! Ouwch!!

So,watch this space...........

Edit 2:
And there are other advantages of making your suggested bracket fit my diff.
1 I can make it now, before I complete my car.

2 All my current components are known to fit - there is a possibility the Ultima diff could be wider across the flanges? - that would almost certainly be a none starter, if its the case.

3 I can make sure the bracketry fits within the space the Cabrio tank has around the diff, whereas the Ultima koala diff case may foul the tank and require modifications - these would be possible, but preferable to avoid.

So, since you've made me think it through more clearly, a new hybrid 'koala' Sierra set up it should be.........................unless I find an Ultima one before I get it made!

Thanks GOO for the prompt.

Mike

I'd like to say I laboured long in Autocad to create it, but it'd be a fib.

It's just good ole MS Visio. I just set the grid to 1 x 1 mm and get it to snap to it, and then create complicated shapes by combining several simpler shapes.

It's how I create my engineering drawings for class.

I have a Sierra 3.36 diff of them sat on the bench, ready to be fitted to my dads Sportster. Cost me a few £££ but worth it as at the moment 3.16 is a little slow off the line.

Jono

Or you could do this Mike:

http://passionford.com/forum/restorations-rebuilds-and-projects/392264-bmw-m3-diff-into-a-sierra-cosworth.html

Which might be easier to find, you would still have to fabricate the stronger diff mount but at least the diff woulf be readily available in loads of ratios.

I had heard there were propblems with the ultima diffs due to a viscous coupling used in the internals but not sure how common it is.


John

Jono
Is your father's Sportster Ford based?
Is the diff a Sierra 3.38 diff, or a Granada 3.36 LS Diff?
Mike

Jeepers - that's some commitment to getting a new diff!
In all my readings the standard diff can cope up to 350-400BHP, so what is this guy putting through it!

It is interesting that he has made his own back plate for the BMW diff to suit a Sierra.

I quite like GOO's idea to make a bracket to bolt on to the back of the Sierra diff I have to make the 'koala' double rubber bush connection.
The more I think about it, the more sense it makes to me.

Mike

Its Ford Based, Sierra back-end, 3.36 or 3.38 but it is a Sierra though as it is 7" across the top where the main bolt goes whereas a Granada is 7 1/2".

Jono