Trying to figure out vibration problem. How exactly do you measure pinion angle, etc. New to this so appreciate everyones help.

Kevin

I went to harbor freight and bought an angle finding tool. It was like $10 and it had a 90 degree angle with magnets on it and a full circle dial that when you stuck it to your drive shaft it told you the angle, i took my angle @ a few spots to be sure.

I think you should do a search for pinion angle in this Brakes and Suspension section. I would have to go research again as it has been about a year and a half since I set mine but If I remember right I measured the angle on the engine at the flat verticle surface where the starter is. I then measured the angle on the flat surface of the pinion yoke that is attached to the rear axle housing. If I remeber right the engine read 91 degrees and the pinion surface read 88 degrees giving me three degrees down angle.

DO NOT TAKE THIS AS CORRECT AS I JUST SHARED MY MEMORY OF WHAT I DID. Memory has a way of getting a bit wrong with time!

If you do not get an answer email me and I will go through my shop for my adjustment notes. I had it in a word document that I lost when my hard drive died! I clearly remember that measuring the angle was easy - changing it was not.

first the car has to be on a level surface and set at regular ride height. you need an angle finder or bubble protractor, with magnetic sides. (these are at sears hardware)then you take a reading at the rear of the driveshaft, let it hang from the bottom just in front of the rear u-joint and for example your angle would read 3 degrees down(or 93 or 87 degrees depending on which way the tool is facing)then you take a reading from the pinion yoke or the housing center section if you can find a suitable surface, and you find that angle to be 2 or 3 down this means you have a total of 6 degrees neg pinion angle, to much s/b 0 to 3,4 neg. you could find that the driveshaft is neg and the pinion is pos. thats ok as long as it equals 0 or less, we do not want to have a positive angle.

The pinion angle is supposed to be measured relative to the trans output shaft. Not the driveshaft. And the car does not need to be level.

Search in the transmission forum. A couple threads have been posted about pinion angle over the summer.

Tim.

Tim, no offence meant, but I think you are wrong. The trans. output shaft is in line with the engine. Please look at http://www.si.hhs.nl/~rob/images/other/angle.jpg

Both setups are used to avoid vibrations. The upper is used in our Chevelles. Angles F and R should be as equal as possible under normal driving conditions and load, but not greater than 5 (depending on RPM). Both angles are relative to the prop. shaft.

Rob

Any text go along with those images? I am under the impression you want to create what is shown in the bottom picture.

TC Tread (http://www.chevelles.com/cgi-bin/forum/ultimatebb.cgi?ubb=get_topic;f=28;t=003424#000000)

Link 1 (http://www.iedls.com/ptsetup.html)

Link 2 (http://www.buickperformance.com/Pinion.htm)

And on and on. But I do see some other references to measuring against the driveshaft and to setting it up like the top picture in your post.

:confused:

Biggearhead, who built my rear end always references the site in Link 1 so that's what I follow.

Tim.

if any one is interested you can email me your fax #s and i will fax the text and diagram supporting what i described in previous post, this information was taken from the chassisworks seminar.it clearly states that the point of this is to check and or set the working angle of the ujoint, which would be the driveshaft and the pinion flange not the engine block or trans, look if someone decided to pump their air shocks or bags from 20psi to 150psi and the whole car raises up but the rear axle stays in the same place, don't you think the working angle is going to change? the engine and the trans have not tilted but they are probably sitting higher and therefore your shaft angle has changed thats why you measure off the shaft. :rolleyes:
john