pinion angle

[68400BIRD]

I'm working on setting the pinion angle in my 1968 Firebird. I'm installing a 12 bolt that was originally out of a 1968 Camaro. The perch pads had already been removed.

This is what I have right now. The car is not on a level surface but the car is on it's suspension and is sitting on the ground.

Front u-joint cap that is closest to the output shaft on the tranny 2 degrees angling down.

Drive shaft closest point to tranny is at about 0 degrees.

Driveshaft closest to rear pinion has a angle of about 1-2 degrees angling down.

U-joint cap closest to pinion has a angle of 4 degrees angling down.

I put the driveshaft at 0 degrees closest to the pinion and the lower u-joint cap on the pinion had a angle of about 2 degrees angling down. I added in two more degrees angling down to get to 4 degrees and that put the drive shaft at 2 degrees angling down. If needed I could shim my tranny mount up a few degrees or shim the rear a few degrees one way or the other.

Does this sound close enough to weld it solid???
I also have this posted over on pro-touring.com

Thanks for any help you can offer.

[Vegas69]

The u joint you measure needs to be at a 90 degree angle to the ground, same with your pinion u joint. The drivshaft should be at close to the same angle no matter where you measure it.

[68400BIRD]

I started with positioning a socket onto the bearing cap and then putting a level on the socket to make sure it was exactly level before taking my measurements.
I don't have access to a completely level surface. My garage floor was sloped for a center drain back when it was biult in 1958 and my driveway is not completely flat either.
I was under the assumption that the angles should all be realative to each other since the car is bolted together.

Remember I know just enough about this to be real dangerous which isn't helping any.

[Vegas69]

Then your pinion should angle up approx. 2 degrees. The easiest way to describe it is the pinion and drivline need to be parallel. What rear suspension?

[68400BIRD]

Originally Posted by Vegas69

Then your pinion should angle up approx. 2 degrees. The easiest way to describe it is the pinion and drivline need to be parallel. What rear suspension?

I'm running leafs in the back with a advertised drop of 1-1.5 inches. The one thing that had me concerned was that I thought the pinion should never be angled up and that it should have a 4-6 degrees of angle down due to it raising up when put in drive and torque applied to it.

[Vegas69]

I figured you were running coil overs since you removed the perches. However, you don't need that much compensation for leaf springs. I really don't know the answer but would guess 2-3 degrees for pinion wrap.

[68400BIRD]

LOL The perches were removed when I bought the rear.It would be a lot easier if they were still on there. It was in a 41 Chevrolet coupe. The PO went to a Ford 9" and sold me the rear end for my car.

[ironworks]

Originally Posted by Vegas69

I figured you were running coil overs since you removed the perches. However, you don't need that much compensation for leaf springs. I really don't know the answer but would guess 2-3 degrees for pinion wrap.

2 degrees on a link suspension and 4 on a leaf spring suspension.

[67rstbkt]

Here's a PDF I found awhile back on pinion angle from Inland Empire -

EDIT - Sorry, it exceeded the file limits. Let me know if you want it and I'll e-mail it to you.

[68400BIRD]

Originally Posted by 67rstbkt

Here's a PDF I found awhile back on pinion angle from Inland Empire -

EDIT - Sorry, it exceeded the file limits. Let me know if you want it and I'll e-mail it to you.

I have looked at that website more than once. LOL From all of the reading that I have been doing I found that a couple of sites tell you to never start off with postive pinion angle. Again from what I have been reading most motor tranny set ups are in at a negative 3 degree angle. So that right there would tell you that you have to angle the pinion up 3 degrees to be parallel. But then you are suppose to add in any where from 3-6 degrees of negative pinion angle for wrap up. Can any one see why I am getting confused? LOL Any suggestions??????