Hot Rods Allowing for 9" Ford chuck offset?

1941 Willys (Small-block Chevy with 700R4 Transmission) :
I have a Ford 9" (75' Granada) housing with no offset, after installing the third member into the housing (On the floor), it looks like the rear yoke is off center about 1".
Should I center the complete rear-end equal in the wheel-wells or should I center the rear yoke to the transmission tail shaft?
>>>I read way back that centering the yoke is more important than centering the complete rear-end assembly in the wheel-wells... Because the drive shaft is short (34" U-Joint to U-joint) & it may vibrate, even with the correct Pinion angle.

 

center the rear end on the frame , the driveshaft running at a slight angle won't hurt

FWIW....i don't consider 34" center to center on the u-joints short

 

I would not recommend offsetting the axle assembly to one side in order to center the pinion.
Many vehicles, including the one your axle came from, ran an offset pinion. Others opinions differ, but the joints only 'see' one angle, just "clocked" at a different point when the pinion is offset in addition to driveline angle.

That said, I can understand your concern the angle may be a bit much with the short driveshaft. If you can measure the angle, and it is in the lower single digits (i.e. up to maybe 5 degrees), I would think that would be acceptable.

If not, your best alternative maybe to start with a wider rear axle assembly and have it narrowed on one side to center the pinion. You may have a 9", a few Granadas did, but most were 8", which at a glance looks much the same. A quick way to tell is if the lower passenger side nut that holds the center section into the housing can take a socket.....or requires a wrench because it is shrouded by the pinion case. If it is the latter, it is a 9".

Ray

 

Yes, I am sure it's a 9" rear (I have a few of them)...

I'm still concerned about the Non-centered Yoke because...
I'm running the S-10 Blazer frame with it's stock S-10 rear-end which is not centered in the wheel-wells and it "Doesn't" vibrate now... I'd be an unhappy guy if it vibrated because I decided to center the 9" in the wheel wells!
I'm thinking that the rear can take only 1 offset, (Either at the Yoke, or the Pinion angle)
but not both!
(Presently running the stock S-10 rear end and a 2 degree (Downward) pinion offset... No vibration)

 

Offset is not the same thing as pinion angle. A great many factory differentials are offset with no ill effects. As long as they're running in the same plane, you can offset quite a bit with no problems, just look at any 4x4 front or rear differential. The only way to upset the plane would be to put one wheel more forward than the other, or to rotate the engine (looking from the top) so that the output shaft was not pointing inline with the rest of the car. I wish I could draw you a picture here.

If you center the yoke like you described, you're running the chance that the car is going to "crab" or "skateboard" down the road, meaning that the body will "yaw" as the car travels in a straight line because your front and rear wheels will be tracking in different lines.

 

An old millwright taught me that a driveshaft should be offset by one eight inch per foot minimum. Keep the yokes parallel and offset the shaft. It doesn't matter up and down, side to side or both. All those little needle bearings are there for a purpose. They should be spinning around the cup. If the shaft is straight they will not spin and you'll get brinelling in the cups and on the pins.

 

Never figured out why guys start peeing in their shoes when they see a bit of offset to the pinion when many factory rigs runs such an offset. At the same time offsetting the rear axle so one wheel almost sticks out of the wheel well and the other is tucked way in and neither is centered on the front wheels is silly as all hell.
As 36 Window said center the axle (wheel mounting flange to wheel mounting flange) on the frame and be done with it.

 

If you are really worried about it, center the rear wheels, then offset the engine a bit. Many engines are offset in production cars. Wife's Dart is about two inches over to pass side, my Chevy II is about 11/16". this is measured at the trans mount.

 

If you are a circle track racer than the 1"offset may help you. If you are driving it then center the rear end. a 1"offest on the hurt you much. unless the rear has been narrowed it was offset from the factory wasn't it.

I got a 9" in the shop now that the yolk is 2" off center. It came from the factory that way. Lots of them don't have the yolk centered,

 

Hey Beaner,
I hate it when my yolks are off center. Almost ruins my breakfast.

 

Built many 100's of chassis with a 9" housing centered rear which put the pinion 2 inches to the right. No problems.

 

Well then the yolks on you.

Uh its yoke for the uninformed.

 

I scramble them, it don't matter if they're off center.

 

You mean the yokes on me? What am I, an ox?

 

Hey ,my chickens are not laughing ,cut it out.

 

Fact #1-the 9" pinion is offset 15/16". Fact #2-many factory engines, as stated above, are offset to the passenger side, the same or close to that model's pinion offset, negating any offset angle. Fact #3-any horizontal pinion/u-joint angle in a chassis with a centered engine/trans has to be added to any vertical u-joint angle, as the two angles result in a compound angle. The shorter the driveshaft, the greater and more critical the angles become. To ensure long u-joint life, design the chassis for u-joint working angles of 3 degrees max.
Spend some time with the link below, and all your u-joint/driveline questions should be answered.

http://www.waterousco.com/media/wysiwyg/pdfs/content/J3311-1-DSSP.pdf

 

That was a fowl statement.

 

they aren't really added, are they? because the diagonal measurement of a rectangle, is less than the length of one side, plus the length of the other side.

Example, if there is two inches vertical offset, and one inch horizontal offset, then the resulting offset, at an angle, is only 2.24", not 3".

 

I was told there would be no math today.

 

I had this 9" housing made with the pinion centered. You can visibly see the difference now that the pumpkin is not centered as it normally would be in the car.

 

Your right Jim, I didn't state that correctly. It's not a whole number addition. The squares of the two angles are added, but the resulting number's square root is the compound, or true operating angle, like your example above.

 

Question:
"How did the pumpkin get to the middle of the road?"
Answer:
"Two short axles."

 

OK, I'll consider it (Leaving the the Axles centered in the wheel wells)...
If you consider pulling over when you see my driveshaft on the ground
& my car on the side of the road, LOL!!
THANKS FOR YOUR REPLIES!

 

THE END.....

 

Just check them out closely a bit more often then you might do on a stock rig and life is good. That little bit of offset isn't going to cause problems near as much as the jacked up 4x4 setups do and you don't see those guys getting too worried about it.

I've dropped the driveshaft out of my 48 with a Camaro rear end with the pinon centered just because I didn't pay attention to the U joints close enough so it's as much maintenance as it is the way it's set up. In my case it was like the shoemaker's kids running barefoot because I spent all my time working on other peoples rigs.

 

I used to see a lot of Chevy Novas do that.

 

I saw a 1968 Nova race around the corner and lose the axle C-clip (Stock rear-end),
it made a mess of his wheel opening!

 

Either ox or religious I suppose. I personally would prefer Ox but I am a little off center.

 

So, if you were a piston in an engine you wouldn't quite reach TDC!