Help with pinion angle...

CCX33911 · #1 (**permalink**) 01-06-2002, 03:58 PM

I have a Jag IRS. Currently there is a mismatch of the transmission down angle and the pinion up angle (if these were equal the center lines of the transmission and rear end would be parallel). My mismatch is about 1.5 degrees. What is the maximum allowable?

ERA535 · #2 (**permalink**) 01-06-2002, 04:31 PM

Can't you rotate the diff up or down?

CCX33911 · #3 (**permalink**) 01-06-2002, 06:00 PM

With the Contemporary the diff mounts to a fixed plate on top with 4 bolts. I could make a tapered shim if necessary. I was just trying to determine if I need to go to the trouble to make a tappered shim (~4" x ~3") with ~0.090" taper. Not real easy.

Cobra20646 · #4 (**permalink**) 01-06-2002, 06:53 PM

How about raising or lowering the tranny a wee bit? You are correct to bring the centerlines to parallel and non intersecting. But I don't feel that a degree and a half is worth the bother..... unless the horizontal offset results in an angle of more than 6 or 7 degrees.
- Jim -

COBRAMIKE427 · #5 (**permalink**) 01-06-2002, 07:23 PM

IS THERE VIBRATION?

ohekk · #6 (**permalink**) 01-06-2002, 07:40 PM

Speedway Motors has tapered shims for this purpose.

available in 2 degree & 4 degree.

Speedway Motors 402-323-3200

Bob Putnam · #7 (**permalink**) 01-07-2002, 05:51 AM

Don't worry about 1.5 degrees of non-parallelism. The miniscule variation in in/out speed will be absorbed by tires and normal drivetrain flex.

Roscoe · #8 (**permalink**) 01-07-2002, 07:16 AM

Try this site:

http://www.iedls.com/guide.html

Roscoe

dalola · #9 (**permalink**) 01-08-2002, 08:21 PM

I confess I know nothing about the Jag IRS rearends, so perhaps they are different, but most solid axles on a street car should have 4-5 degrees of pinion angle. Also, the electronic angle finders are a really slick way to set/measure it. The better ones self-calibrate, and are very accurate.

Dave

Bob Putnam · #10 (**permalink**) 01-09-2002, 03:58 AM

Do not confuse setting up a moving (live axle) rear end with a stationary one (independant).

Now read my first post again.

Sonny · #11 (**permalink**) 01-09-2002, 06:38 AM

over the long haul, a little 1 dgree or so variation will actually keep the short drive shaft preloaded and possibly eliminate any drive shaft vibration from wear/tolerances. most short shafts are not balanced by the shops only phased for the joints, so they tend to be out of balance slightly.