Axle ratios

[Tom W]

Personally I can't see the point; most say it's to lessen the rotating mass, but if you're taking it off the crown wheel and adding it to the carrier (or vice versa) it's going to come out pretty much the same either way.

The point is simply one of geometry. The wide spread of ratios can’t be achieved simply by changing the diameter (number of teeth) of the crown wheel alone. With the taller ratios, the crown wheel can’t be so small that it doesn’t co over the carrier, and with the lower ratios, it can’t be so big that it doesn’t go inside the housing. So to achieve the ratio spread, the pinion size changes too, which changes the lateral position of the crown wheel.

I don’t think the flange width changes, just the position, so it’s not a case of adding material to one and taking it off another. but if you search for Peter’s photo this should clarify things.

[Hugo]

Ah - thank you; the way I read it (on an American site) was that the flange on the carrier was a different thickness to accommodate different thickness crown wheels.
Now it makes sense - and I like it when things make sense.
I had a brainwave late last night - what's to stop me machining 3/16" off the carrier behind the left hand bearing, to push the whole ass.y over to the left a bit? I fitted it all together last night minus the left hand outer bearing race. The rollers on the left were sitting against the diff housing, and there was a 3/16" gap on the right between the bearing and the diff housing. I shoved the left axle shaft in to centralise it & lightly clamped the right hand bearing. And it worked like a dream. Feels right - and backlash feels spot-on. So I figure why not make it permanent by machining the left side of the carrier where the bearing sits, then space the right hand bearing out a similar amount.
I now eagerly await a dozen replies telling me why this won't work ;)

[politeperson]

I have a couple of Dana 2.88s kicking around. You can have one for £50 if you want. They are large heavy units. They are not popular for E-types because you also require the XJS brake setup as well. No drain plug as Peter says. You need to use the E type dog bones. The so called Salisbury unit goes straight in.

These guys have quite a few near Derby.

http://www.justxjs.com/

This (below) explains where they were fitted in the first place.

https://www.coventrywest.com/salisbury- ... iff-do-i-h

I have rebuilt the 3.54 to the 3.07 ratio but at the end of the day, the time and cost involved was much greater than putting a V12 2.88 in (with new seals).

[Hugo]

I still have the spare empty 2.88 Powr-Lok carrier (subject to confirmation) if you want to pm me. I didn’t see anyone mention the lack of a drain plug on Dana cases by which you can immediately tell a bare empty casing is Dana. They were used intermittently in the mid 80s on XJ and XJS. I still have the 2.88 from my 84 XJ12.

I tried to send a PM but apparently you don't exist. I might well be interested in your 2.88 carrier as it would solve my difficulty. But you are in America? And I'm stuck in England (as is my car) having caught practically the last flight out of Florida a month ago and with little prospect of getting back before the summer.
If you want to come back with details (i.e. $$$$) via PM that's fine, as I do receive them. And if it tries to tell you I don't exist, it's lying ;)

[mgcjag]

Hi Hugo... click on a useres highlighted name...it then displays their profile.....you should then see a highlighted.. Send private message...click on it....Steve

[Hugo]

I have a couple of Dana 2.88s kicking around. ....

Sent a PM - thanks.

[Philippe-J.]

To you IRS experts

I wanted to have the axle ratio of my american E changed from 3:54 to 3:07.
The workshop I employed warns me that they should grind few mm out of the housing to give space to the new crown. I was not aware about that. Do you confirm this has to be done and it is safe?
Or is there another way round?

BTW, is there anything else to check?

Thanks for your help.

Edit: Alan Slawson informs me that since Brexit he does no more work nor export outside UK. If you have ideas for another way...

[mgcjag]

Hi Philippe...iv never heard that grinding the case/houseing? is required....the go to diff man is Alan Slawson at http://www.ajsengineering.com/ contact him and mention your a forum member...Steve

[angelw]

Philippe Wrote

The workshop I employed warns me that they should grind few mm out of the housing to give space to the new crown

Hello Philippe,
I would seek another workshop, for the one you have doesn't know its arse from its elbow.

Going from 3.54 to 3.07 no modification is required. It's when you want to fit a 2.88 that a modification is required.

Regards,

Bill

[Hugo]

I did exactly that - 3.54 to 2.88. I had to machine the (thicker) crown wheel down a bit to get it to fit. It hasn't broken yet!
I believe Jaguar used a different carrier on the 2.88?