Pinion Angle???

When you set you rearends pinion angle does it need to be up 3 degrees or down 3 degrees in relationship to the center line of the motor and transmission? Thanks Kennedy

 

It sets down. And yes, down from the driveline not zero.

 

I was always taught that a line through the crankshaft, AND a line through the pinion should be parallel in all planes, though NOT directly inline.

Inline would lead to abnormal U joint wear, through no motion of the bearings (see Chevrolet van, 1970-1992).

The three degrees down was to compensate for torque reaction with leaf springs, the thought being that the torque would wrap the springs that much in normal driving.

I set mine parallel, which sometimes means that the driveshaft runs uphill (viewed towards the rear), sometimes level, and sometimes downhill. Parallel is parallel, no less, no more.

Cosmo

 

I knew this thread would spawn controversy....I was always taught to pitch it down 2 degree's

 

This is the method I think most people use. Drag racers recommend setting it down, but the driveshaft place that did mine said for cruisers, it should be parallel to the transmission. For example, if the tranny is down three degrees, the rear is up 3 degrees. This link probably describes it better:

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

I pointed mine down 2 degrees and it doesn't vibrate, but I plan to shim it if something changes.


Bryan

 

For a street driven car, the pinion angle should be up 3 degrees in the front. All V8 engines are designed so that when the carb bases are level, the engine/transmission output shaft pitches down 3 degrees at the rear. It would be almost impossible to have the pinion shaft and transmission output shaft directly in line, unless the engine was setting extremely high in the chassis, so the issue of having them directly in line rarely comes up. Drag racers do pitch the nose of the pinion down slightly. so that under extreme acceleration forces when the springs wrap up and the frame tweaks a bit, the pinion angle will deflect into the 3 degrees up position that is desired.,

 

Those engine swap books that Hot Rod magazine put out in the 70's and 80's say to run the pinion parallel with the trans output. They even include a neat little illustration of it. But what do they know about cars anyway. Idiots! I have always installed them parallel and they work great. Probably just a fluke.

 

brainangus,

Not all V-8's are made that way. Some are, some are not. I always set the engine parallel to the ground and the pinion parallel to the ground, though not the same height.

Matt