Rear Axle: 63 Avanti Pinion angle Photo

[karterfred88]

Does anyone have a picture showing the approximate angle of the driveshaft to pinion angle from the side of the car, with the tire off looking in toward the universal joint, but not on a lift? Mine appears to have too much angle, but since the traction bars seem to hold the rear angle more than any wedge between the spring plate and spring pack would, I can't see a way to minimize it. When backing up, the spring flex makes it worse, binding the u joint and making the driveshaft "ring" when it forces itself past the binding. It appears someone "worked" the front half of the springs to lower the rear, but I can't see how re-arching the spring would change the angle much and the traction bar rubbers are already "compressed" like they have been forced to fit, as if the bars themselves are too short. Maybe looking at a photo with everything in the "right" orientation will help me figure out what was done wrong and correct it?

[Alan]

Fred; The Avanti spring is not the same length front eye to locating bolt as it is to the rear eye. That causes a change in angle as weight is placed on the rear end. Easier to show you a few pics.

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[Mike Van Veghten]

Sounds like you need new springs.
The factory bars should have "no load" on them at ride height, and little load when the car is lifted.
Not positive on the Avanti, but since it's the same frame as the rest of the Studebakers, the pinion angle at ride height should be zero, or very close (with the nose up if anything).
I know when I measured the spring pads on my 54 vs. the pinion, the spring pads are welded with zero angle to the pinion gear. So any angle will be in the spring.
The engine/transmission is similar, tailshaft down by the engine damper. They should also be parallel as looked at from above, even with the engine sitting to the right side of the car.

Remember, always check angles with the suspension at ride height (all four tires on the ground/blocks, etc.

Mike

[karterfred88]

Thanks Alan,
I can see one problem already--my spring arches upward between the front bushing and first leaf then back down. I'll remove my wheel and put a jack stand under it tomorrow and post a few photos. Where are your traction bar mounts on the axle?
Fred

[Alan]

Fred; Those are modified 65 Dodge ramcharger springs. The stock Avanti springs are bent so that they look like they were put in a press and V'ed right behind the eyes. I did not like the stock bars that sit on top of the axle, so I did not use them. I am using stainless steel slapper bars that I built myself. If you need UHMW bushings for the stock bars just give a yell.

[StudeRich]

Fred, I would not try to compare your Car to anything on Alan's Car, there are no Studebaker Parts there except the frame.
It has some nice Custom work, but no Stude. Rear end or springs, so very little to compare to.

[DEEPNHOCK]

At ride height..... (whole car...suspension loaded... at ride height)
Measure your crankshaft angle (trans output shaft is the same thing)
Set your pinion one degree down in relationship to the trans output shaft angle.

(if your crank angle is 2 degree's down, then set your pinion angle 1 degree up)

Whatever you put into the u-joint (angle wise) in front, you take that out in back.

Drag racers put more 'down pinion' to negate pinion rise on accelleration.
Street cars should be neutral.

The reason for the angle up and angle down is for the u-joints.
If things are perfectly aligned all the time, the u-joint rollers will not roll and will oscillate and end up brinelling the cup and cross shaft, shortening u-joint life.
Also, a mismatch of angles, or an extreme of angles, will give you vibrations either under acceleration, or deceleration.

Some interesting reading here:

https://www.google.com/#q=street+car+pinion+angle

Some pictures at:

http://tinyurl.com/pinion-angle-pictures

[jpepper]