Open driveline phasing ?

R

russcc

Well-known member
As I understand it, an open driveline has to be in phase at the transmission and rear axle pinion. I believe I saw a recent article in Hot Rod or HRD on that by Freiburger. Any help would be appreciated. Merry Christmas to all the Fordbarners. Thank you.
 
Phasing simply means the yokes are indexed at exactly the same location. In most situations this is "built-in" to the driveshaft.
 
You will get varying opinions on this subject, but here is my take. The driveshaft should NOT be in in a perfectly straight line from trans to rear end, even if it were possible. The joints at each end have to move a little to keep the bearings from sitting in one spot and wearing little grooves in the cross of the u-j0int. Generally accepted desired angles are 3 degrees or less. Sometimes it is necessary to exceed the 3 degrees and I have done it with no adverse consequences YET after 70,000 miles. The typical transmission points downward at the u-joint connection. The rear pinion flange should point upward an equal amount. Another way of stating it is that a line drawn from the ends of each shaft should be perpendicular to each other.
 
Here u go
 

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40cpe said:
You will get varying opinions on this subject, but here is my take. The driveshaft should NOT be in in a perfectly straight line from trans to rear end, even if it were possible. The joints at each end have to move a little to keep the bearings from sitting in one spot and wearing little grooves in the cross of the u-j0int. Generally accepted desired angles are 3 degrees or less. Sometimes it is necessary to exceed the 3 degrees and I have done it with no adverse consequences YET after 70,000 miles. The typical transmission points downward at the u-joint connection. The rear pinion flange should point upward an equal amount. Another way of stating it is that a line drawn from the ends of each shaft should be PARALLEL to each other.
Click to expand...

I think.
 
The previous posts will be correct with regards to set up when building a car, however that is not quite what the question means.
Consider a basic propshaft with 2 universal joints and finished at each end with a flange.
As the power/ drive, rotation is applied to the input flange it turns at a constant speed, HOWEVER that drive as it is transmitted through the first U.J. goes through four phases (90degrees of each) as it does a revolution. Faster slower faster slower. These speed changes are the speeds the main body of the propshaft does, until reversed at the rear (second) universal joint. Ultimately the result is a smooth even rotation speed at the back flange. This only happens if the center lines through the two universal crosses are in line (phased) otherwise a permanent vibration will be built into the car.
This is always the case with a Universal joint, and why they are found usually in pairs. (not always the case) (one compensates for the other)
This is why the other types of joints are called CONSTANT VELOCITY JOINTS
 
Essentially, yes, But I dont recall it being there when I posted.
How does that work?
With regards the movement to lube the U.Js. Ford has (in some models, at least )moved the engine in some cars over to one side, and additionally moved the front of the engine to 1 side.
 
But there are exceptions...never did understand why some cars like 1967-1969 camaro have the u joints at wierd angles..if the front driveshaft yoke is horizontal then the rear yoke is like 20 degs off vertical....
 
GM was experimenting with improving "u" joint life and stopping ANY vibration. Didn't work. Better mousetrap, so to speak.
 
There are some vehicles that have independent rear suspension that use 2 u joints for each axle plus u joints on the drive shaft.(Total of 6) Each u joint can be installed 180 degrees off. when installed out of phaze operation is greatly affected more so at slower speeds I think most drive shafts have the yokes on the drive shaft where they are correctly indexed lee34
 
Anyone care to explain how CV joints in front wheel drive cars work??

Also, I think that our beloved torque tube drive cars have the engine and everything lined up to be close to in line with the driveshaft so that the U joint sees very little flexing and the "velocity change" is minimized, having only the one joint without a second one to cancel out the change. (IMHO)
 
The Early ford U-Joint has bushes rather than needle rollers, so the opposite rule applies.. Keep the deflection down to a low angle. The Early Ford also has the ability to take up any slight misalignment between the centres of the trans and drive shafts. That's why you can feel end play(slop) in them.
As stated above, more modern UJ's have needle rollers and need a certain amount of movement to keep the rollers circulating and to not "brinell" the surfaces. As the joint is normally used in a driveshaft, the UJ has no end slop so it can effectively keep the shaft centred.

Mart.
 
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