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If i want to switch the rear diff for a quaife one, do i really need the version that includes flanges?
Quaife search results for escort cosworth

Caddyshack

I don't know if you need the flanges. The quaife diff will no doubt be better but the weak point is the crown wheel and pinion. I suspect that the quaife needs properly setting up.

For good advice and an expert opinion and info try speaking to Bara at Bara motorsport near Birmingham, he did my front quaife, rear supra diff and oppliger close ratio box

steveboyslim

If you switch to a Quaife you will need the flanges as the original Ford ones do not fit, I you use a Gripper the originals can be modified and used.
The CWP are reasonably strong but the pinion bearing wears and the excess movement levers the teeth either off the crown wheel or the pinion gear.
With the standard diff the sun gears have bevel washers these wear and then with the extra movement get fired through the rear diff cover.

Steve

ajamesc

Crown wheel and pinion reasonably strong lol. This is what good grip from a gripper diff and r888's and about 450/500lb ft of torque dose






And that's not driving like a twat that was flooring it it 2nd exiting a roundabout. No wheel spin it gripped and went bang.

Marc sierra

iTrader: (1)

But 450/500 lbft is quite a lot, it's between 2 and 2.5 times the standard torque. I know that running high torque on a RWD kills the diff easily, but on a 4x4 1/3 of the torque is going to the front. So if you have 450 lbft, there is 'only' 300 lbft going to the rear. So I think normally the rear diff on a 4x4 shouldn't really be a problem.


But of course you also need some luck. I know a guy who broke the input shaft to the pinion gear in half on a 7.5" diff with a standard 24v BOA engine.


http://i442.photobucket.com/albums/q...psd6ecdb6d.jpg

Caddyshack

Mark Shead often said that the rear diff should not be too much of a problem but I changed it anyway to be safe. He Said if I go launching on sticky tyres and doing donuts etc it would break. Dont forget that in the scenario above it broke in second off roundabout but the damage could have been done by other types of driving before hand and those are very sticky tyres when warm.

The gearbox will fail sooner or later at that power on a standard car

cossie2

...mine LSD rear diff from Titan motorsport is working well...Got it through Mike R some few years ago..

Caddyshack

Check out the for sale section, there is a front and rear quaife in there at good prices. They look like they have been done by Bara

https://passionford.com/forum/ford-r...-reardiff.html

steveboyslim

Was the diff its self checked and then rebuilt with new bearings checking the mesh of the cwp and bearing preload before fitting ?
The slightest bit of bearing wear will cause lift in the pinion gear which is the start of potential damage like you have shown.

Steve

ajamesc

I built it so yes done properly! New pinion bearings new crush washer new diff bearings. Back lash pinion hight and pinion drag all set to fords spec

steveboyslim

The crush washer probably helped with the failure, make a spacer and grind to size to achieve the correct pinion bearing preload.
Did you crack detect the cwp ?

Steve

ajamesc

What goods a spacer lol the washers there to crush until you get the right pre load on the bearing. Would take ages to get the spacer just right size. What caused it was high torque good grip and small crown wheel and pinion. When I picked up the gripper diff unit I said to the guy is it strong I won't break it will I? He laughed and said no your break the crown wheel and pinion 7 months later a loaud bang and that lol

steveboyslim

Using a spacer instead of a crush washer has been proven to help any movement in the pinion bearings since the days of MK1 & MK 2 escorts, the crush washer was done only as a method to speed up production.
Gartrac built all my axles that way, many Group N and Group A & WRC 9 '' diffs were also rebuilt the same way.
You are correct it takes ages to get the spacer to the correct length to give the correct bearing preload, which is why most do not bother.

Steve