Too much Pinion Angle

[slmcrewchief99]

I have a friend thats running an 07 shaw mod thats having pinion angle problems. When this happens it get so much angle the drive shaft yoke is binding in the rearend yoke and breaking it. To get that much angle it has to get to probably 12degs positive or negative. The car is set at shaws specs on pinion angle. The car is on a pullbar setup. The biscuits are fresh. Only a couple of nights on them. He had this happen a few years ago and the pinion was bent. Put in a new center section and all was good. Thought this was the problem this time but its happened with 2 different center chunks. And 1 of those came out of a shaw mod that was running fine with it. So can anyone give me a guess as to what he is missing. I told him to put a torque arm under it and he would be good to go. But they are illegal so thats out. Any imput will be greatly appreciated.


thanks,
Alan

[calif54]

Brooks/Shaw chassis school recommends setting the pinion angle at 7-8 degrees. They also recommend measuring the pinion angle by adding the angle of the third member/rearend to the angle of the driveshaft to determine the final pinion angle. Not just the angle of the third member. I bet if you check, you probably have way too much static pinion angle.

[dirttrackrocker]

This is all too common.. Most people don't realize that to measure pinion angle correctly, you have to account for the angle in the driveshaft as well. If you have 7 degrees at the pinion and your driveshaft is going up towards trans at 5 degrees, then you have 12 degrees.. I would bet money this is the case..

[big88fan]

yep they are right I did the exact same thing and with the really short pullbar on my shaw car it made the angle under load even worse but hey it only took 3 new drive shafts before we figured it out:(

[frontrunner]

ok guys how bout if u want 6 degees pinion does that mean u got 2 have 3 degrees on pinion & 3 degrees on driveshaft becouse I always went just off of the pinion and how would u do this with the pinion and driveshaft 2 get it right??? Thanks

[Flyin Iowan]

i would ask the chassis builder....mine just goes off the pinion plate

[dirttrackrocker]

First measure what your drive shaft is at ride height. If it is at 2 degrees and you want 6 then go 4 on your pinion. Where you run into problems is when you have the engine and tranny raised and your driveshaft angle gets to 4 or 5 degrees, then you put 7 on your pinion and now you have 12 degrees.. That won't work...

[frontrunner]

Ok thanks but if If change my pinion my driveshaft angle moves with it also. Like u said if I want 6 degrees pinion, ok if my drive shaft is 2 degrees and I need 2 get my pinion at 4 degrees hows that work becouse when I move my pinion angle to get 4 degrees my driveshaft angle moves with it also so how do u do it??? Thanks again

[frontrunner]

Oh yea mine is a leafspring car should it matter???

[dirttrackrocker]

Just measure both each time you make an adjustment till you get the 2 to add up to your desired angle.

[frontrunner]

ok I got 3 on drive shaft but when I try to get the rgt degree on pinion now the driveshaft is differnt & still not rgt.... When I have the drive shat rgt & then I get the pinion rgt then the driveshaft is back off im not understanding what am I doin wrong????? Thanks again

[dirty white boy]

ok I got 3 on drive shaft but when I try to get the rgt degree on pinion now the driveshaft is differnt & still not rgt.... When I have the drive shat rgt & then I get the pinion rgt then the driveshaft is back off im not understanding what am I doin wrong????? Thanks again
put shaft on yoak,...rotate rearend till shaft an yoak avrage out to 7 degrees or what ever number you feel you need,...cant set one then other,..gotta set both at same time....

[frontrunner]

ok thanks ? im running stacked leafs & always ran 6 degrees off of 3rd member i never did do the driveshaft & pinion together that way ? but what will happen if I did the shaft & pinion together 2 get the 6 defrees and its not sopose 2 b dne that way on my car??? And does anyy body that runs stacked leafs do it this way or how not???? Thanks again 4 the info......

[dirttrackrocker]

Angle is angle, doesn't matter if you have leafs or not. You can be a little more forgiving with leafs because the rear doesn't rotate as much.

[frontrunner]

What should I set my pinion at? & should I do the driveshaft & pinion & how do I know if I should do the driveshaft & pinion or just set the pinion by itself???? What pinion angla 4 stacked leafs????

[HEAVY DUTY]

You should be ok on a leaf car with 6 0r 7 degrees at the yoke. Basicly with any rear suspension if you feel a vibration coasting off the throttle you need to take some pinion angle out, and if you feel a vibration on the throttle you should add some or stiffen what ever controls your pinion wrap up (pullbar, front half of leafs etc.)The heighth of the tranny tail shaft and the height of the pinion, change the u joint angle some as does the misalignment side to side at rideheight and during chassis movement.

[frontrunner]

ok thank u for the info......

[dirty white boy]

lotta good tech if you google drive line angles...
http://www.drivetrain.com/parts_catalog/drivetrain/driveline_angles_and_phasing_problems.html

http://www.carcraft.com/howto/91758/index.html