Brake rotor centering

[WSSix]

Watching the video Donny posted, they reiterate that the working angles need to be the same between the two u-joints while showing the working angles at each end being fairly extreme. Which is more important? I can rotate the nose of the pinion up more easily than bringing the tail shaft of the transmission up. That would get my angles the same between the two joints but the angles would be more extreme. I'd be simply doing this as a test to see if it effects the vibration at all.

I swear I've done this before and it had no effect on the vibration. Then again, I swore my angles were good, too.

Also, if I were to nose the pinion down 3.5 degrees to match the tail shaft, causing the drive line to look like this \ _ /, wouldn't that cause the drive shaft to become unstable or bind?

Thanks everyone.

[Vegas69]

Your current working angles per your measurements are within .5-1 of each other. 0-.5 is ideal so you are close.

What you are describing with the pinion pointed down 3.5 is exactly what I just talked about. You are getting your working angles on both ends of the shafts as small as possible. It takes some trial and error. The problem with this strategy is that you may get an oscillating vibration. When the working angles are equal and opposite, you get a consistent hum or vibration, when they are not you will get a stronger vibration followed by none.

Equal and opposite and small working angles gives you the smoothest operation.

[WSSix]

OK, I think I'm getting confused. I'm going to do some more reading and get back with you guys. I think I'm getting my terms mixed up or something.

Based on the measurements I have given, what is my pinion angle?

Thank you

[randy]

Do this All angles are measured on the drivers side of the car.

1. engine/trans is on ____ angle and it heads down in the back. Meaning the crankshaft is higher than the tail shaft

2. The Driveshaft (if not there use a string or a piece of wood to go from the center of the output shaft to the center of the pinion) is at a ___ angle and it heads down in the back. The connection at the transmission & driveshaft is higher or lower than the connection at the rear diff to driveshaft. Does water from from the front driveshaft down to the rear or would it run from the rear to the front towards the engine

3. the pinion is at a ______ angle heads up or down in the back. The driveshaft and pinion create a V or a /\ ?. Would water placed on top of the diff run behind it or onto the driveshaft.

Base on this we will figure out the rest.


To give you an idea my angles were close but still caused a vibration and the aluminum bigger driveshaft fixed this. Mainly because the driveshaft was very level and caused a jump rope effect not to mention the driveshaft shop high speed balanced my new one.

[Vegas69]

2.5 degrees UP from level.

Your tailshaft is DOWN 3-3.5 from level. If this is true it puts them close to the same plane.

This is exaggerated: Tailshaft: \ Driveshaft: / Rear: \

[randy]

i just dont see his driveshaft going up from the trans to the rear diff. My car is Low and i know its a 1st gen but i still have 1 degree down on my driveshaft angle. If his driveshaft is going up my guess is that he is measuring his engine angle wrong. The crank pulley and fuel rails were the easiest spot for me to measure.

[SSLance]

Trey, make sure whatever you are using for an angle finder is EXACTLY straight front to back for each measurement. It being just a bit off skew can really mess with the numbers.

And run to harbor freight and get a digital gauge if you don't have one already. The needle gauges are way inaccurate in my opinion.

[WSSix]

Originally Posted by Vegas69

2.5 degrees UP from level.

Your tailshaft is DOWN 3-3.5 from level. If this is true it puts them close to the same plane.

This is exaggerated: Tailshaft: \ Driveshaft: / Rear: \

Thank you. That's what I've been thinking and saying but the number of articles and information pages I'm reading that say the pinion angle is the difference between the drive shaft angle and the angle the pinion is placed at is staggering and it pisses me off, lol. It's just confusing me because in my mind the difference between the angles is the working angle not the pinion angle. Just wanting to make sure I'm communicating properly.

Originally Posted by randy

i just dont see his driveshaft going up from the trans to the rear diff. My car is Low and i know its a 1st gen but i still have 1 degree down on my driveshaft angle. If his driveshaft is going up my guess is that he is measuring his engine angle wrong. The crank pulley and fuel rails were the easiest spot for me to measure.

I measured at the balancer just a minute ago and it's showing 2.5 to 3 degrees up from level which causes the tail shaft to point down. I think I'm going to invest in a digital angle gauge so I can stop expecting this manual gravity one to be accurate. It's hard to read as well.

If you stand on the driver's side of the car moving from front to back, my drive line looks like what Todd posted \ / \ .

Thanks everyone

[Vegas69]

The face of the U Joint is the best place to measure all the angles. I used a socket and angle finder, but a magnetic finder would be much easier as you could stick it right on the u joint.

[randy]

Originally Posted by WSSix

Thank you. That's what I've been thinking and saying but the number of articles and information pages I'm reading that say the pinion angle is the difference between the drive shaft angle and the angle the pinion is placed at is staggering and it pisses me off, lol. It's just confusing me because in my mind the difference between the angles is the working angle not the pinion angle. Just wanting to make sure I'm communicating properly.



I measured at the balancer just a minute ago and it's showing 2.5 to 3 degrees up from level which causes the tail shaft to point down. I think I'm going to invest in a digital angle gauge so I can stop expecting this manual gravity one to be accurate. It's hard to read as well.

If you stand on the driver's side of the car moving from front to back, my drive line looks like what Todd posted \ / \ .

Thanks everyone

that makes no sense. the engine cant be angled up and the trans pointing down at the same time.

I have this one
https://www.amazon.com/Floureon-Incl...l+angle+finder