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Stock Pinion Angle

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I made the dumb move of not measuring the stock pinion angle of the driveshaft before changing the springs. Now I want to put a 1 piece d/s in the car and need to know what the angle should be to avoid vibration. Anyone have any idea?
 

Senderofan

Having more fun than should be allowed..in my Boss
Sarosh:

I'm sure someone here can provide you specs from Ford. I can offer what I did and the measurement I had. I used a digital level...this one: http://www.summitracing.com/parts/lng-78311

My measurements were done with the rear suspension loaded and the vehicle raised and pretty much level...as level as the floor is. The very bottom of the differential has a long flat surface that runs parallel to the length of the car. I used this surface for my measurements. My measurement my not be terribly helpful since you are on a different surface etc. But I measured 86.5 degrees before lowering and 86.4 after. I believe my digital level has an accuracy of +/- 0.1 degrees so I felt I was within the margin of error.

Through my studies on the subject before the installation..... I surmised having the angle too far up is worse than down....since the differential ( pinion angle) wants to twist upward under heavy load which would exaccerbate an already too high angle. Like you, I could not find specs from Ford.

Hope I haven't wasted bandwith or your time with this post. Hopefully someone can provide concrete numbers to assist in your project.

Have a great weekend!

Wayne
 

Justin

Save the dawn for your dishes!!!
This is what you would ideally set it to

~If all the control arms have Factory bushings: Set Pinion Angle 3 degrees to 4 degrees downward.
~If all the control arms have Poly bushings: Set Pinion Angle 2 1/2 degrees to 3 degrees downward.
~If all the control arms have Solid bushings: Set Pinion Angle 1 degrees to 1 ½ degrees downward.

http://www.baselinesuspensions.com/info/pinionangle.htm
 
Installed a Dynotech one piece alum DS, along with Steeda Boss lowering springs. Per Steeda, these springs lower the rear of the car about .8", but on my Boss it's closer to 1". I did not change the pinion angle, and the car runs perfectly smooth and vibe free all the way to redline in 5th gear.
 
dabossinne said:
Installed a Dynotech one piece alum DS, along with Steeda Boss lowering springs. Per Steeda, these springs lower the rear of the car about .8", but on my Boss it's closer to 1". I did not change the pinion angle, and the car runs perfectly smooth and vibe free all the way to redline in 5th gear.

I had my dynotech ds w/ hotchkis springs for about a month, vibe-free upto about 140. I already had a DSS, so I installed that and its been vibe free as well. I just feel better knowing I have the cv joint back there. -1 is a good angle for a true one-piece. If your car is a drag-car only then the -2 to -4 applies.
 
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I already bought the dynotech shaft months back so the DSS is not an option. Everything I have read about pinion angles calls for the transmission and diff to be parallel. Do you guys concur? Of course this is only applicable to non CV shafts to ensure alignment. Therefore I think it is more important to align those two systems rather than aim for a specific angle. My uca is stock and my lcas are cortex, so poly bushings.

I'll report back when I get underneath the car. Thanks for the [email protected]
 
sadil said:
I already bought the dynotech shaft months back so the DSS is not an option. Everything I have read about pinion angles calls for the transmission and diff to be parallel. Do you guys concur? Of course this is only applicable to non CV shafts to ensure alignment. Therefore I think it is more important to align those two systems rather than aim for a specific angle. My uca is stock and my lcas are cortex, so poly bushings.

I'll report back when I get underneath the car. Thanks for the [email protected]

You'll need a UCA and mount. Make sure to have the car on ramps/drive-on lift when measuring. Its a bit confusing the first time you do, then it clicks. The trans shaft will point down(lets say 3*) and the pinion needs to point up about 2* for a car that doesnt drag-race(for a total of -1*). So your measuring one and subtracting the other to get your actual pinion angle. The tricky part w/ this platform is that the trans shaft is not level than the pinion, so it will never be perfect w/o shimming/shaving trans mounts and such. Thats why I pressed the easy button and got the DSS. Thats my understanding at least. YMMV
 
1,022
97
Exp. Type
HPDE
Exp. Level
10-20 Years
Texas
Justin said:
This is what you would ideally set it to

~If all the control arms have Factory bushings: Set Pinion Angle 3 degrees to 4 degrees downward.
~If all the control arms have Poly bushings: Set Pinion Angle 2 1/2 degrees to 3 degrees downward.
~If all the control arms have Solid bushings: Set Pinion Angle 1 degrees to 1 ½ degrees downward.

http://www.baselinesuspensions.com/info/pinionangle.htm

My question is where did you measure the angle from? Did you use the flat surface in front of the diff?
 

Justin

Save the dawn for your dishes!!!
Flyboygsxr said:
My question is where did you measure the angle from? Did you use the flat surface in front of the diff?
I did mine from the flange. I think if you youtube search setting pinion angle you will see a video posted by cjpony parts they show you exactly where.
 
Make sure the car is on 4 ramps or a drive-on lift. Measure the trans output shaft angle, and take a carpenters square and measure the pinion flange. The flange isnt easy to put a angle-finder on w/o using a carpenters square. Measuring from the same side of the car, you want to subtract the pinion angle from the trans angle. i.e -3 trans and -2 pinion would equal -1 total pinion angle. Its not easy to figure it out the first time, but once you do it will make sense.
 

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