Hello All,

I noticed that my '68 coupe drive shaft (350 engine/M20 tranny) has the yokes attached 45 degrees out of phase with each other. In other words, the yoke on one end is aligned at a 45 degree angle to the yoke on the other end. My mechanic friends say they've not seen this before - they've been taught that yokes should align with each other.

Is this unusual? The drive shaft is not twisted and the welds look to be stock.

Thanks -

Melsman

Normal, GM did this trick to keep the driveshaft under tension while torque is going through the shaft to cut down on harmonics and vibration.

OK - thanks for the response!

Is that how a shaft is supposed to be assembled? The shaft that I got when I did the TKO conversion has the yokes welded the same way. In fact, my original GM shaft has them welded the same direction also.

First gen. Camaros are the only shafts that I ever saw with the yokes out of phase like that when I was rebuilding drivelines. Even Nova shafts of the same years are in phase.

If you were to get an aftermarket shaft or had your original re-tubed, the end yokes would be lined up in phase with each other.

Mark

If it's really 45 degree's,then that's to much, and NOT a original Camaro shaft. A Camaro shaft should be about 33ish Degree's out of phase.

Well - I didn't measure it... it could be 33 degrees vs. 45. I ASSUMED 45 only because it was definitely not aligned and it appeared to be split evenly.

So, what was the logic behind 33 degrees vs. 45? (Or for that matter, aligned like every other driveshaft?)

Always learning something new...

Melsman

Search for the thread "Cyclic Vibration", read Post #13. Use 33° rather than my posted 15°.

Regardless of degrees or the reason for such angles, it didn't work on my car when new or after. Even when I had the joints in phase the car vibrated. Solution? Shim the rear end UP 6°. Like butter now.
I've heard that GM built the first gens (at least 69's) out of phase because the rear end was lowered at the pinion so as to allow the car to be fully loaded with five people and not have the shaft rub or the diff riding on the tunnel stop. Don't know if it's true but it if it is, it sounds like the marketing department had more power than the engineers.

For what it's worth mine was about 15deg.

Regardless of degrees or the reason for such angles, it didn't work on my car when new or after. Even when I had the joints in phase the car vibrated. Solution? Shim the rear end UP 6°. Like butter now.
I've heard that GM built the first gens (at least 69's) out of phase because the rear end was lowered at the pinion so as to allow the car to be fully loaded with five people and not have the shaft rub or the diff riding on the tunnel stop. Don't know if it's true but it if it is, it sounds like the marketing department had more power than the engineers.

Very true! If your angles are bad,it's gonna shake no matter what. I'm not sure why Chev did that and have heard many different stories.So far not many of them make much sense. Every now and then,we have someone who wants a Driveline as close to original as possible and want it out of phase like the original. If the shaft is straight & balanced, and the angle's are good,I've had pretty good luck with vibrations with those shaft's.

I still prefer to build them in phase. Both of my Camaro shaft's are built in phase.