Drive line angle/pinion angle

[DonB]

I've finally got my engine,trans and a new 8.8 rearend in place and was wondering about the angles. My 8.8 measures 4.3degrees tilted up. At the output shaft on my AOD it reads 1.5 degrees tilted downward. I was told I need 3 degrees at each u-joint. This is on a CMC cobra. Does this change with the body and seats etc installed? I figured it would be easier to adjust angles while it was in the early stages.

[392cobra]

You need "Equal but opposite".

It is easier now but the reading will change after it is finished.Go ahead and do it but you'll need to do it again after it is loaded and at the finished ride height front & rear.

[bobcowan]

Do a search for "pinion angle". Here, google, and the other cobra site. You'll find lots of posts, including pictures and diagrams.

As it sits, your pinion angle is waaaay off. It needs to be measured at proper ride height. You could set it now, as long as you're at ride height. When you add seats, fuel, etc, you'll have to re-set ride height. But then pinion angle should not change.

[MaSnaka]

Don,
There was a pretty extensive discussion on this very matter at the Classic Roadsters forum recently. I believe it's titled body vibration by Scott. I know it's a different model but the theory would be the same. There were some detailed references discussed and debated with some outside resources as well. I think you need to read into the 2nd page. Good luck.

John

[Ant]

I have mounted my 8.8 on the same angle as the engine/trans, so if the engine is pointing down slightly the diff should point up the same angle, so in effect both centrelines are parrallel. Also driveshafts should never be straight as the needle roller bearings will wear in one place and brinelling or excessive wear in one spot will occur.

The operating angles on each end of the driveshaft should be equal to or within 1 degree of each other, have a 3 degree maximum operating angle and have at least 1/2 of a degree continuous operating angle.

When the transmission output shaft centerline and axle input shaft centerline are parallel, the u-joint operating angle permissible is length of driveshaft divided by five. Example: A short coupled driveshaft with a 15" length would be limited to 3 degrees maximum operating angle. A 30" shaft would be limited to 6 degrees.