Offset pinion and pinion angle

Just a quick thought here and I would love to hear some opinions. The 9" in my model a has an offset pinion so the drive shaft angles toward the passenger rear of the car. Can I run less of an up/down pinion angle because the sideways angle will already help to lube the u joints. I have the engine mocked up at 3 down at the tail shaft and 3 up at the pinion, but Id really like to lower the engine a little in the front for firwall clearance and visual appeal. Thanks in advance for your thoughts guys!

 

You bet you can.

 

No.

The up/down angles should still match. If you are at 3º, stay there. If you need to move the engine and trans, move the pinion too.

It is not just about circulating the lube in the u-joints, it is about cancelling out the non-uniform velocity of the u-joint at the operating angle. They do not move at a constant speed.

When viewed from the side, you can see that u-joints, at any other angle but 0º, operate in an ellipse. That results in a speeding up and slowing down of the joint. This must be offset by an opposite movement at the other end of the driveshaft.



From Tom Woods: "If you were to watch a "U" joint move through an angle (the operating angle) from an end view . You would see that the joint in the driven shaft has to move through an ellipse. Because the joint has to move through each of the quadrants of this elliptical path in a fixed amount of time, the velocity or surface speed of the driven shaft increases & decreases 2 times per. revolution.

With a conventional two joint drive shaft, if your second "U" joint has an equal or intersecting angle , The second "U" joint will be decelerating at the same time and at very near the same rate that the first "U" joint is accelerating, resulting in a smooth power flow through to your pinion.'

 

How many degrees of articulation does the u joint need to lube properly? Can I add the two offsets together? ie 1 dgree down, 2 degrees offset=3 degrees articulation?

 

All you need is adequate, opposing angles at either end of the drive line. It doesn't matter if it's up and down, side to side, or a combination of the two. It'll work just fine.

 

Gimpys: Ya I would absolutely change pinion angle to cancel the tailshaft, thats a given no worries there

 

Ditto!

 

An angle as little as 1º, as measured between the trans output shaft center line (or pinion), and the driveshaft center line, is sufficient to circulate the grease and move the bearings.

THAT angle can be on ANY plane.

 

Gimpys: were talking about the same thing here, just in different words, its all good. My hypothetical setup would be 1 down at the tailshaft, 1 up at the pinion and 1-2 offset both front and rear caused by the offset pinion.

Thanks for all of the input guys! I love the HAMB

 

Ah ha! Makes sense now. Coffee still has not kicked in yet. Off to get another cup.