setting pinion angle???

[transmaro93]

hey guys i might put the car up on ramps today and try to set the pinion angle the best i can so i can at least drive it without having to worry about f-ing up my rear...i figured on going with a -2 degree angle. is that a good angle to have? but my question is how do i measure this correctly. and also im assuming that negative angle would be the pinion pointing down a bit in relation to the driveshaft... am i correct on that? thanks in advance for any help

ps car is lowered about 1.2-1.5 inches in the rear, t56, strange 12bolt, umi adjustable trans crossmember mounted tq arm.... incase that helps... car is a street strip car that will probably see more street time but will be raced hard when its ready to hit the track... thanks again

[KirkEvil]

You need a magnetic angle finder, and make sure you measure from the passenger side with these directions...

http://www.ls1tech.com/forums/suspen...ion-angle.html

[98tadriver]

i went on LS1tech and i believe it was Madman himself who said something like- disconnect the driveshaft from the rear, set the rear at -2 degrees and dont worry about anything else. i did that with the trans am and had no problems.

[Pampered-Z]

This is so hard to explain without diagrams!

Because the car is lowered you also want to take into consideration the engine/trans now sit lower in reference to the rear then whem stock. You are reducing you drivetrain angle.

Pinion angle is relative to drive line angle, the difference between the crank and pinion, with the pinion pointing down.

If you don't have a true base on the pinion, you first have to know what angle the crank is on ( it is not parallel to the ground, it points down some degrees), and you can't reference the oil pan! You will need to use something like a square off the balancer hub, assuming it's flat, or measure the front center of the crank and the rear of the crank (could use the center of the tail shaft). So that you can determine the downward angle of the crank and transfer that back to the pinion to find the angle at which the pinion is at zero, then angle down the pinion -2.

Without know what angle the crank is on you only adding negative angle between the drive shaft and pinion you can be putting too much negative angle on the pinion which will stress the universals. This is why with a lowered car or aftermarket K-member you may need to shim the trans mounting bracket down or shim up the trans mount to being the entire drive line back into alignment to eliminate high speed vibrations or positive angle.

[transmaro93]

man... i never made it out last weekend.. but this sounds more complicated than i thought it was going to be... ill let you know how i make out... thanks for all the help guys

[Mark42]

Being the old school hot rodder, all the instruction I ever had was to be sure the transmission output shaft and pinion shaft are in parallel planes. The angle from the trans shaft to drive shaft and pinion shaft to drive shaft should be the same. That formula always worked fine for me.

But as with anything, there is always some design/exception to screw up some good basic rules that are easy to follow.