Pinion Angle Help

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Vcode

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64 Dart 273 with 4-speed setting on the ground. I measured the angles and this is what I came up with. The 4-speed transmission trunnion flange right at the end on trans is 2.75 down
The 8-3/4 rear at the yoke was 1.10 up
What does that come out to. Any adjustment needed for a stock driver.
Thanks Bob
 
You understand the angles are measured from the orientation of the
drive shaft NOT the angles from the ground (That is irrelevant).
 
I guess what I mean is the car is setting down on the ground with the body weight and the rear in the proper locations.
I used the angle gauge to get the angles of the car and not the ground.
Bob
 
I guess what I mean is the car is setting down on the ground with the body weight and the rear in the proper locations.
I used the angle gauge to get the angles of the car and not the ground.
Bob
The driveshaft angle I got was 1.50 down
 
The best way I know to explain it is with a picture. Your numbers don't have to be the same as this example. What you are after is to have the same working angle at the front that you do at the rear.
DRIVELINE ANGLE.png
 
If I understand you correctly it means there is a 1.65 degree difference
 
I put my numbers in on the picture graph. Trans down 2.75 Degrees
Driveshaft up at trans end and down at rear end 1.50 Degrees
Rear end up 1.10 Degrees
I am still lost on the calculations of up and down, where do I add and where do I subtract.
 
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You want your rear yolk to be DOWN about two degree from your driveshaft
on your 4 speed car NOT up!
When you drop the clutch the rear end will lift and the yoke will point more
upward than static.
 
I added the numbers to the Spicer calculator. Angle 1 =1.30 Angle 2 =2.55
Looks like I need to lower front of rear to equal 2.75 down and that will make it 1.30 like trans
 
I put my numbers in on the picture graph. Trans down 2.75 Degrees
Driveshaft up at trans end and down at rear end 1.50 Degrees
Rear end up 1.10 Degrees
I am still lost on the calculations of up and down, where do I add and where do I subtract.
Post #5 explains it 100%. I don't know how it can be any more clear.
 
They make different degree wedges that go between
the springs and rear end. i would put a one and a two degree together.
Any spring shop or Summit or Jegs should carry them
 
Correct, I need about 3.5 to 4.0 degree wedges to get the rear facing down 2.75 to match up with the trans angle.
 
Correct, I need about 3.5 to 4.0 degree wedges to get the rear facing down 2.75 to match up with the trans angle.

More likely to have vibration issues if you point the pinion down that far on a street driven deal. Those shim numbers give you a 5.1 to 5.6 down pinion, more than normal.

My deal and the way a lot of people do it. Under power you want the pinion, which rolls up under power, to be parallel with output shaft. In your case the trans is point down 2.75*. To get the pinion parallel, it needs to be pointing up 2.75* under power. So this is a guessing game of sorts. Measure with drivers weight in seat.

If you rolled the pinion down 2*, you'd be at .75* up. I usually run up to about 4* down on street cars. Race cars, especially leaf spring cars with no traction bars can go a lot more than 4* down.

JMO, for your car, if street driven, where it is would likely be OK at 1.10* up. A range of .75* up to 1.25* down would be my target if being nitpicky. If you don't have shims run it as is and see what you get. If it vibrates under acceleration, roll it down inside that range mentioned. See if the vibration goes away.

It's the relationship with your output shaft that tends to matter so the u joints phase properly. Rarely have we ever had to take the driveshaft angle into account. Exceptions, when the DS was pointing at an extreme angle.. like a lifted 4wd situation. And very rare occassion on cars.

Just my two cents.
 
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