### Post by fugly on Mar 10, 2010 14:03:42 GMT -6

As originally posted by Mopar Dave on the old site:

mopar dave

pinion angle

« on: April 07, 2009, 12:37:31 PM »

whats the correct way to measure pinion angle. one guy says measure relative to the drive shaft and another says measure relative to the trans angle? my trans is +4, driveshaft +5 and pinion is -8 nose down. running SS 002/003 springs and snubber on an A body.

also, i will be converting to ladder bar set up at end of this season. what should the pinion angle be with ladder bar? thanks

fugly

Re: pinion angle

« Reply #1 on: April 07, 2009, 01:45:30 PM

The best way to do this is with the car supported

on jackstands, with stands underthe rear axle

tubes, with the full weight of the car resting on the stands. Next,

it's best to remove the driveshaft. Using an angle finder,measure across the surface

of the rear transmission seal vertically. This

surface is perpendicular to the output shaft of the trans, so

subtract the measurement from 90 to get the drivetrain angle. Let's

say that the measurement is -2 degrees(pointed down). That is our

reference point. The pinion angle is the difference in the angle of the rearend to the angle of the drivetrain. So, in order to have zero pinion angle, the rearend

would have to be tipped upward (pinion yoke pointing upward) 2

degrees. If our drivetrain angle measured -5 degrees, we'd have to

tip the rearend upward 5 degrees to have zero pinion angle.

Now turn the pinion yoke so that the u-joint cups are sideways, and

measure across one side of the pinion yoke vertically where the u-joint strap connects. Again, this surface is perpendicular to the pinion, so subtract the measurement

from 90 to get the rearend angle. compare this number to the

drivetrain angle to get the pinion angle. If the drivetrain angle

was -2 degrees(pointed down), and the rearend angle measured +1

degrees(pointed up), then the pinion angle would be -1 degree. If

the drivetrain angle had measured -2 degrees (pointed down) and the

rearend angle had measured -4degrees (pointed down) then the pinion

angle would be -6 degrees. The idea is to have

the pinion angle at zero with the racecar under power and going down

the track. To allow for suspension movement and loading, the pinion

angle should be at around -2 to - 3 degrees .

mopar dave

Re: pinion angle

« Reply #2 on: April 07, 2009, 01:58:55 PM

ok, i did that with the car on the ground and trans angle was 4* down and the pinion was 8* down. so whats my pinion angle, 12*?

fugly

Re: pinion angle

« Reply #3 on: April 07, 2009, 05:20:14 PM

yep-

mopar dave

pinion angle

« on: April 07, 2009, 12:37:31 PM »

whats the correct way to measure pinion angle. one guy says measure relative to the drive shaft and another says measure relative to the trans angle? my trans is +4, driveshaft +5 and pinion is -8 nose down. running SS 002/003 springs and snubber on an A body.

also, i will be converting to ladder bar set up at end of this season. what should the pinion angle be with ladder bar? thanks

fugly

Re: pinion angle

« Reply #1 on: April 07, 2009, 01:45:30 PM

The best way to do this is with the car supported

on jackstands, with stands underthe rear axle

tubes, with the full weight of the car resting on the stands. Next,

it's best to remove the driveshaft. Using an angle finder,measure across the surface

of the rear transmission seal vertically. This

surface is perpendicular to the output shaft of the trans, so

subtract the measurement from 90 to get the drivetrain angle. Let's

say that the measurement is -2 degrees(pointed down). That is our

reference point. The pinion angle is the difference in the angle of the rearend to the angle of the drivetrain. So, in order to have zero pinion angle, the rearend

would have to be tipped upward (pinion yoke pointing upward) 2

degrees. If our drivetrain angle measured -5 degrees, we'd have to

tip the rearend upward 5 degrees to have zero pinion angle.

Now turn the pinion yoke so that the u-joint cups are sideways, and

measure across one side of the pinion yoke vertically where the u-joint strap connects. Again, this surface is perpendicular to the pinion, so subtract the measurement

from 90 to get the rearend angle. compare this number to the

drivetrain angle to get the pinion angle. If the drivetrain angle

was -2 degrees(pointed down), and the rearend angle measured +1

degrees(pointed up), then the pinion angle would be -1 degree. If

the drivetrain angle had measured -2 degrees (pointed down) and the

rearend angle had measured -4degrees (pointed down) then the pinion

angle would be -6 degrees. The idea is to have

the pinion angle at zero with the racecar under power and going down

the track. To allow for suspension movement and loading, the pinion

angle should be at around -2 to - 3 degrees .

mopar dave

Re: pinion angle

« Reply #2 on: April 07, 2009, 01:58:55 PM

ok, i did that with the car on the ground and trans angle was 4* down and the pinion was 8* down. so whats my pinion angle, 12*?

fugly

Re: pinion angle

« Reply #3 on: April 07, 2009, 05:20:14 PM

yep-