1" Right Hand "offset" of Jag Differential Output Pinion...Remedies?

[MrWumper]

I mentioned this in the post I made about bottom mounting the Jag IRS, but I think it got lost in there...

The output pinion on my Jag Salisbury differential is offset 1" to the right, and I assume that all Jag IRS's are designed this way; am I correct in this assumption? Or do some models/years not have this issue? I can see this causing some major headaches, especially with a short wheelbase/short driveshaft set up.

How have others alleviated this problem, or, for that matter, is it really a problem? Does anyone know how to calculate "potential" driveshaft angles without a driveshaft of the correct length to do the mock-up? Pleeeease don't tell me I'm going to have to mount my entire engine offset to the right!

Why did they offset the pinion in the first place??

[mylesdw]

I'm pretty sure all Jag diffs are the same. I guess they designed it that way so that the crown wheel sat dead centre and then the drive shaft components can be symetrical, you don't need left and right handed components.

As long as the gearbox and axle flanges are parallel to each other there should not be an issue with a slight offset. The drive shaft on my car is about 12" long and there seems to be no problem.

[MrWumper]

That's about how long my driveshaft is going to be...and I was worried about angles on the U-Joints being too great and causing premature wear, but you say you have no problems? Do you happen to know offhand the U-Joint angles on your driveshaft?

[mylesdw]

I will climb under and measuure this evening...

[xlr8or]

Remember you don't want it dead straight either or the bearing won't turn in the cups and will wear prematurely.

[MrWumper]

mylesdw---Thanks for the offer to climb under there...but I was just wondering if you had the angles off hand. You don't have to go climbing under there if you don't want to....

xlr8or---"Remember you don't want it dead straight either or the bearing won't turn in the cups and will wear prematurely." Really?? I know I don't want it completely straight in the vertical plane, but in the horizontal plane? Aren't almost all differentials made with their output pinions dead center?

[mylesdw]

No problem, car is up on stands at the moment anyway.

Propshaft is 16" long and the offset it 1" as you describe. By my reckoning that gives an angle of approximately 3.5 degrees.

[xlr8or]

I believe so long as you have some angle either horizontal or verticle it will be sufficient to cause the bearing to rotate in the cups as the driveshaft turns. You might want to do a search here on pinion angle for more details.