I know this has probally been discussed before. I am trying to eliminate a vibration problem. I lowered the front suspension around 2 inches but left the rear at stock height. The pinion angle of the engine block and or tranny tailshaft is -2 degrees pointing downward toward the rear of car. The rear end yoke is at +2 degrees pointing up towards the front of the car. The driveshaft is at -4 degrees pointing downwards toward the rear of car. I know that the pinion angles are supposed to be in a parellel line with each other. I also know about rear end wind up at speed. Since you can not change the angle of the engine block. Should it be some negative offset in the rear end yoke or am I OK with this setup?
1969 Pinion Angles
ontheball2
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I know this has probally been discussed before. I am trying to eliminate a vibration problem. I lowered the front suspension around 2 inches but left the rear at stock height. The pinion angle of the engine block and or tranny tailshaft is -2 degrees pointing downward toward the rear of car. The rear end yoke is at +2 degrees pointing up towards the front of the car. The driveshaft is at -4 degrees pointing downwards toward the rear of car. I know that the pinion angles are supposed to be in a parellel line with each other. I also know about rear end wind up at speed. Since you can not change the angle of the engine block. Should it be some negative offset in the rear end yoke or am I OK with this setup?
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Pinion angle is compared to the drive line angle, not the horizon. This is the key point that a lot of folks don't get.
If your drive line angle is 2* down, and your differantial angle is 2* up, then your pinion angle is 0* at rest.
Optimal theoretical pinion angle is -2*. As you apply power, the pinion will rotate and point upwards by about 2*. That makes your pinion angle 0* under power. Which is perfect. In theory.
But in your case, I wouldn't think that 0* of pinion angle at rest would cause a vibration.
If your drive line angle is 2* down, and your differantial angle is 2* up, then your pinion angle is 0* at rest.
Optimal theoretical pinion angle is -2*. As you apply power, the pinion will rotate and point upwards by about 2*. That makes your pinion angle 0* under power. Which is perfect. In theory.
But in your case, I wouldn't think that 0* of pinion angle at rest would cause a vibration.
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I had a vibration issue with the angles correct. I found that the tailshaft bushing on the trans. was worn. The slip yoke could be moved around when inserted into the tailshaft. I replaced the bushing which eliminated the slop and vibration.
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The vibration started right after I lowered the front. It vibrates real bad at exactly 70-75mph. Maybe it is just a coincidence. But I had all 4 tires rebalanced and there was no change. It does not vibrate thru the steering wheel but you can feel it all in the front section of the car. Like the dash,front floorboards. You can almost see the hood shaking. Right after it first started to vibrate I got a manifold leak. I did find a distorted out of place manifold gasket and chewed up exhaust donut on the passenger side making me think that it is a possible torn motor mount.I did check the mounts while in gear with my better half giving it some gas and the motor seemed to me to move too much and raise up. I have new mounts on order and maybe this could be the problem.
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