Pinion angle?

[71scamp78]

74 Challenger I swapped in a Gen 3 hemi and 8 speed now have a pretty bad drivetrain vibration. The engine/trans in angled down 2.5 front to back. The drive shaft is 1.9 down front to back. The pinion is .5 up . Any suggestions how much to shim and up or down . Or do u think its not the problem . It's a leaf spring car

 

[Jim Ward]

74 Challenger I swapped in a Gen 3 hemi and 8 speed now have a pretty bad drivetrain vibration. The engine/trans in angled down 2.4 front to back. The drive shaft is 1.9 down front to back. The pinion is .5 up . Any suggestions how much to shim and up or down . Or do u think its not the problem . It's a leaf spring car

I set me Duster up equal but opposite as directed by my driveline shop. Check the angle that your trans tail shaft is down and set your pinion up the same angle. I bought a digital angle gauge that is magnetic on the bottom and it worked real slick. I have no vibrations but I’m no expert. Just what I did on my 72 duster.

Jim

 

[71scamp78]

I set me Duster up equal but opposite as directed by my driveline shop. Check the angle that your trans tail shaft is down and set your pinion up the same angle. I bought a digital angle gauge that is magnetic on the bottom and it worked real slick. I have no vibrations but I’m no expert. Just what I did on my 72 duster.

Jim

Trans tail is down 2.4 degrees and pinion is up .5

 

[Jim Ward]

Sound like the pinion needs to come up 1.9 then, based on how I was told to set mine up. I didn’t know if you meant inches or degrees.

 

[66fyssh]

 

[71scamp78]

Sound like the pinion needs to come up 1.9 then, based on how I was told to set mine up. I didn’t know if you meant inches or degrees.

Degrees

 

[AJ/FormS]

All angles are relative to the ground-plane right?
the pinion must ALWAYS be nose-down relative to BOTH the ground-plane and to the driveshaft.
because, as you apply power, the pinion will climb upwards and may end up nose up which is bad.
How much nose down, depends on the springs ability to resist the upwards rotation. Seven degrees is common for a stout V8, in a factory chassis, even with SuperStock springs.. ... depending on the input power.
You may have to juggle the ride-height and the front to rear rake, to get into the ballpark.
You can put a jack under the pinion and lift it to see how soft your springs are, which may lead to different springs.
Remember, these angles have to play nice at speed and under power. At rest or just cruising may have to be sacrificed.

A minimum of 1* is recommended between any two axis, to keep the needle rollers from imprinting on the cross-pins. From 2.5 to 1.9 is a difference of only .6, so you got room for a lil more driveshaft down at the rear.

Is your engine on the same centerline as was the factory engine, or did you center it in the engine bay. This could complicate things.