Phasing drive line?

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Crazy4408pac

Crazy4408pac

N. Michigan
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I don't know if that is the correct wording. Trying to set pinion angle on my 72 Swinger. Has 440, setting on an Altercation, 727, new balanced Al driveshaft, 8 3/4". I noticed, while I had the car in the air, that the tranny, looked like it was pointing a bit to the drivers side, in comparison to rear yoke. So I dropped the drive shaft and attached a laser to the output shaft. I was correct. It was a degree or two off.
Suggestions on correcting this? I know I should address this, before setting pinion angle.
Thanks for any help.
 
There's a huge difference between the pinion and the crank centerline having a one degree "cockeyed" and I'm assuming you mean looking down on it, IE the angle is azimuth, and the other possibility which is the centerlines are PARALLEL but offset horizontally. I cannot imaging having a one degree angle......that's a fair amount, unless your car is visually "bent" or the engine is as far angled as you could ever get in the bay

Hope I have not confused you. An example of shafts parallel but offset either/ and horizontally as well as vertically is something like an older jeep with the offset transfer case. They all worked "just fine."
 
I guess I should have said that the laser point was about 1/4" to 3/8" off from the center of the pinion bolt.(to drivers side) The laser was set at center of transmission yoke. Laser was parallel . I was just eye balling the 1-2 degrees, at the laser.
I'm asking the best solution for moving the engine/transmission enough to have the laser hit center and be in align. Keeping in mind that I'm dealing with an AlterK .
 
If the engine and transmission are parallel with the axis of the car I wouldn't worry about it. It is part of the reason for u joints. If you must address it (depending on tire location in the wheel wells) moving the rear one way or the other may be easier than modding engine and transmission mounts.

Is this slight misalignment causing a problem? Vibration, etc?
 
Crazy4408pac said:
I guess I should have said that the laser point was about 1/4" to 3/8" off from the center of the pinion bolt.(to drivers side) The laser was set at center of transmission yoke. Laser was parallel . I was just eye balling the 1-2 degrees, at the laser.
I'm asking the best solution for moving the engine/transmission enough to have the laser hit center and be in align. Keeping in mind that I'm dealing with an AlterK .
Click to expand...
if ur engine is in the stock location, it`s probably ok. there is "built in the factory" offset , bigblocks usually are 1 1/4' to 1 3/8"offset to the pass side on the front of the engine , which would naturally point the laser to the drivers side of the pinion yoke. the downward angle should be roughly 3* down in the static position-weight on the car. I wouldn`t think the offset on the rear would be that noticeable tho . ?????????? Can u post pics of the laser set up ? never seen one myself, interesting.
 
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Not causing a problem. Just thought I'd address it while I was setting the pinion angle. As noted. Shouldn't cause any problem
As for the laser set-up. All I did was adapt a small round magnet, to the end of a laser pointer. Works great. Cost me 3.07+tax. I set it up on the pinion bolt and it was off the same amount. So, I'm good to go

"If the engine and transmission are parallel with the axis of the car I wouldn't worry about it. It is part of the reason for u joints. If you must address it (depending on tire location in the wheel wells) moving the rear one way or the other may be easier than modding engine and transmission mounts."

Just how would I move the rear one way or the other?
Thanks for the replies.
 
The driveshaft is not to be installed dead on. U joints work to cancel out vibration and do not do their job if they are lined up dead on. A simple "net" search about driveshaft alignment can explain it better the I can
 
I doubt VERY much that you could get the rear axle/ engine centerlines angled "looking down" on them off enough to affect anything so far as U joint angle. With the transmission mounted on the factory crossmember location, there simply is not enough room in the engine bay to angle the engine centerline that far.

If the rear axle is angled far enough to affect the shaft in azimuth, the car would handle so poorly because of wheel misalignment, you would not be able to drive it.

In other words the vertical alignment is what you need to worry about
 
Crazy4408pac said:
I don't know if that is the correct wording....
Thanks for any help.
Click to expand...

The term "phasing" in terms of driveshaft nomenclature is not the correct word for the alignment issue you are asking about. Phasing refers to the orientation or clocking of u-joints in relation to each other on a given driveline.

Combining several simple mechanical properties/functions together into one system with multiple affective parameters seems to be the root of the great amount of confusion and misunderstanding surrounding pinion angles and ideal driveline construction and set-up.

Dr Diff, helped me get a basic understanding of what's going on with this topic, but I still lose my perspective sometimes. These attachments help me keep it simple.

Here's a good read on the topic.

Drive Shaft Harmonics

There is a great video showing the affects of u-joint positioning and the slight increase and decrease of driveshaft speed that result as the u-joints are brought into and out of the elliptical movement patterns by changing their working angles.



Ideally, u-joints work best when installed between two parallel lines that are offset from each. They require a certain amount of offset from parallel to work properly. That amount is described on one of the manufacturers websites tech pages.

Because our drivelines are not fixed in position due to engine torque, suspension movement and other factors, initial settings such as pinion angle are a compromise to get the components aligned within an acceptable range or sweet spot.
 
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