pinion angle?
 

put on a set of Cal-Tracs. need to know what is the best pinion angle?
Specs. 56 Nomad, leaf springs [6 'cause its a wagon] spring pads are 6" long. 9/16" U-bolts. approx. 1725lbs on rear. motor mounted solid, so the trans angle is NOT adjustable.
right now the 4speed to 'shaft is 2degrees. the pinion is about 1/2degrees up from level and there is 2 degrees difference.


I have degrees shims. if I put the pinion down -2degrees, that would make 4 degrees total at the rear. setting the front would change very little. at launch, the front angle should increase approx 2 degrees [front/body rise].
in high gear the front drops down. in theory then, the front angle would be 2+ degrees difference and the rear would be 2 1/2 degrees the opposite direction. sound right or no?
with the long spring pads, I cant see the pinion turning up very much. 6degrees down would be a lot, I think!
thoughts?
thanks Rod in AZ

Re: pinion angle?
 

What you want is about 2 degrees down between the pinion and the driveshaft angle. That way under power the angle will be near zero.

Re: pinion angle?
 

there is no good place to place the magnetic angle finder on a 9". so I made a 5" tab, which uses 2 studs on the pass. side. now, I get 1 1/2 degree up.. so using a 4 degree wedge, I should get 2 1/2 degrees down.

will post real measurements when finished next week.
Rod in AZ

Re: pinion angle?
 

My way of doing it has the driveshaft out of the car. Car sitting on boxes so the chassis weight is on the tires. Have the pinion yoke turned so you can measure off of the flat of the yoke. Place angle finder on harmonic balancer, then place it on pinion yoke, difference is pinion angle.

Re: pinion angle?
 

Eman this is the simplest way to do it. Too many people over think it.

Re: pinion angle?
 

BTW: You can download the Tremec Driveshaft Angle Finder tool for your phone on Google Play...FREE! Useful at the track....or at the shop. Accurate to .1 degree...Works on Android systems..

Re: pinion angle?
 

That's the way John Calvert taught me.

Re: pinion angle?
 

Doesn't tell you the operating angle of the front and rear u-joints, which could be quite different car to car depending on location of engine/trans assembly, ride heights, length of the drive shaft, pinion height in the rear, etc.

I want to know the operating angles of both joints. Rare to have the desired configuration of the front joint near zero and rear joint at the desired number down (negative).