Join Date: May 2009
Location: Shalersville, Ohio
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Pinion angle is relative to output shaft angle, you need both. Each should be equal opposites and the working angle no greater than 7 degrees for 1310 style u-joints. That means if you have a transmission output or axle pinion measuring + or - 9 degrees you're gonna need a CV style 3-joint drive shaft. Even raising the ass end of the car 2" shouldn't even be close to this. Those extreme angles are usually only found on big lift straight axle trucks and Jeeps. Anyway..
An example would be your magnetic angle finder reads -4 on the output shaft and +4 on the pinion, thats perfect cause they are equal opposites.
Say we got -5 on the trans output shaft and +3 on the pinion then id raise the pinion 2 degrees to make both ends -/+ 5. Just remember equal opposites. I have a TKO600 in my '66 with a longer tail shaft than the TH350 that was in it so my drive shaft needed cut down 1.75" to make it work. With my UMI adjustable uppers I dialed in equal opposites at -/+4 and the car drives great. No low speed or high speed drive line vibrations whatsoever and i make 112 mph passes in it.
Now when its track day the recommendation Spohn made to have some negative pinion angle is advantageous. When you slam the gas and hold it open the pinion wants to lift nose up and stay there till you let off. The idea is by setting up the pinion to be down say 1.5-2 degrees at rest for drag racing you now have equal and opposite angles going down the track at WOT by compensating for that pinion lift under that type of extreme load and abuse. For daily driving though make them equal opposites on flat ground and your vibes will be gone assuming you have good joints in the shaft and no other issues like unbalanced tires.
Your lift springs, are they wagon cargo coils or what kind? Might be too dang stiff..
You outta see her on a road course, or a quarter mile
Last edited by Bensjammin66; 07-13-2015 at 12:24 PM.