Pinion angle woes

[Oldboy]

Hello,
I may have posted this before, but i have not resolved this and could use some help.
46 Plymouth, V8, auto trans. Ford posi.
Cannot seem to get my pinion angles right. I am using an angle finder on the trans yoke. Think i may pull the driveshaft and take my angle from the flat of the trans where the yoke would be. I seem to have 5 1/2 degrees down from the trans. Now the diff pinion needs to be 5 1/2 up? But this cannot be because then the pinion is pointed up and I thought that was wrong .
Please weigh in this is driving me nuts. Thanks

 

[Dr Crankenstein]

You're not wrong. The old rule of thumb is crankshaft/output shaft 3° down, pinion shaft 3° up. (Your 5.5° seems excessive.)

You want equal and opposite angles without exceeding the u-joint's working angle. (Crankshaft and pinion shaft must be parallel to each other.)

Flip through this document, ignore the multi-shaft arrangements and note the offset chart which may apply to your Ford diff...

http://media.spicerparts.com/cfs/fi...token=eyJhdXRoVG9rZW4iOiIifQ==&store=original

.

 

[Tripper]

First... you didn't say what type of rear suspension you're using. Rear ends using parallel leaf springs are usually set up at 3-5 degrees because they flex more. 4-link's are a lil more stable & are typically set at 2-3 degrees.

I like to set mine up at 6 degrees total. Engine down 3 degrees with rear end up 3 degrees. Also... I measure the engine's 3 degrees off the intake manifold where the carb sets.

Hope this helps!

BoB

 

[Blue Eyed Devil]

5 1/2 degrees is way too much - 3 down 3 up.

Like Billy Dee says - Works every time...

 

[Old Iron]

Doc, the Spicer page is great for someone trying to wrap their head around this process.

 

[MercuryMac]

I've read the Spicer pages too, and formed an opinion. It seems to me that the working angles of each U-joint is more important than the slant of your transmission and rear-end, [as long as they are parallel]. Hopefully, some of the off-road guys will chime in here, with their really slanty driveshafts.
My opinion is not to be trusted completely because I'm in the middle of healing up a driveline vibration on my '36. I have just lined up my motor and transmission to be parallel to the pinion, on a horizontal basis. We all worry about the vertical driveline angles but I'm telling you to remember the horizontal ones too. I have not test driven my latest driveline change, so have no answers, only opinions.

 

[Oldboy]

Hello,
Yes the rear is leaf spring.
I am thinking i will raise the trans crossmember, or at least bring the angle closer to 3 degrees with spacers. I may have to trim the trans tunnel a bit but am ok with this. Then at least i will have some flexibility with pulling the pinion down a bit. Will strive for 3 degrees each.
Not sure about looking down from the top view, but think they are pretty much in line that way.

 

[Oldboy]

Ok,
Well i clearanced the trans tunnel slightly, raised the tail up about 1”.
Readings with the spicer app resulted in all “green” after entering the 3 measurments. So i locked it down and will hopefully drive the car later.
Post w result.

 

[Oldboy]

After using the Spicer app I got all “green “in the results,
locked everything down putting it back together hopefully take for a ride later and post with results

 

[donsrods]

5 1/2 degrees is way too much - 3 down 3 up.

Like Billy Dee says - Works every time...

Yep, been doing that for years, never a problem with vibration or anything.

 

[Old Iron]

After using the Spicer app I got all “green “in the results,
locked everything down putting it back together hopefully take for a ride later and post with results

Good deal [cl
Be waiting to see the results [P[P[P

 

[Oldboy]

Hello,
Ok , trimmed the trans tunnel, reinstalled the floor, and took it out for a drive. At first impression it seems as though the Vibration is gone.
Need some highway shake down, but think this repair Has worked!

 

[smallfoot]

We knew you could do it![cl

 

[Old Iron]

We knew you could do it![cl

Right On [cl[cl[cl

 

[rustybeercan]

That's what I love about car forums, especially this one! When you have a problem, people are so willing to help. Glad you got it fixed, happy motoring! [cl

Beercan

 

[bob w]

Contrary to popular hot rod building construction, I set the engine level (no tilt) and the pinion shaft level and let the elevation difference between the tailshaft and the pinion shaft determine the angles.

I'm glad you solved the vibration problem.

 

[Oldboy]

Good vibrations

Well
It’s been about two years now since I sorted this problem I have driven the wheels off of this car at this point .
take it out as often as possible.