CV Driveshaft

[old66tiger]

At what point does a CV type driveshaft for the older cars make sense? I have had a minor vibration that has driven me nuts and I am contemplating looking at this solution. I have the situation where the TKO has forced a bit of a pitch in the engine/transmission and adjustable rear arms just can't pull this out of the car. Thanks.

[lees02ws6]

What have you tried so far? What are your angles? Double cardan, and rzeppa joints are possible on one or both ends, but will weigh a bit more. Rzeppa joints heat up when they are at an angle. If either type joint are put at the pinion, you'll need a flange that can accommodate them.

[andrewb70]

....I have the situation where the TKO has forced a bit of a pitch in the engine/transmission and adjustable rear arms just can't pull this out of the car.

^That's when a CV shaft will solve your vibration problems.

Honestly, I think I am the only one around that has done this.



Andrew

[lees02ws6]

^That's when a CV shaft will solve your vibration problems.

Honestly, I think I am the only one around that has done this.

Andrew

I spoke to the Drive Shaft shop a year ago. Eventually I got my angles to a point where the vibration was resolved. however here are their responses:

Q: I understand that The Driveshaft Shop has, on occasion, made cv driveshafts (using rzeppa joints) for older muscle cars. I have a few questions
>
> Are the cv joints used on both ends of the shaft?
> If used on only one side, what angle does the pinion need to be at? Is it similar to a double cardan where you point the pinion at the transmission?
> How much heavier is the cv joint relative to a u-joint? Can common tailshafts like used on the tremec t56 handle the additional mass?
> Are knew slip yokes, with the appropriate flange provided? If on both ends of the shaft, is there a new pinion flange provided as well?
>

A: the angle issue wouldhave to be discussed in detail to give exact infor but for most
we would set the diff at 1 to 1.5 Degrees, the CV is a little heavier maybe 1 to 2 lbs
so its not going to be an issue and the fact that most we have done with a Aluminum shaft
takes it back out of the equasion (also the actual speed balancing takes it out) i have not
had to make then wioth CV's on both ends (for early cars) but can if the angles make it needed
as for the CV it not like a double cardan. its a true CV


to be honest this type of set up is more for a car that can not have the angles put in the proper set up for the
joints, i agree the double carded is poor choice. all it really does it kinda make it 2 small shafts splitting the
angle in half. you will still have a varying velocity joint (not constant like a true CV)

[andrewb70]

I spoke to the Drive Shaft shop a year ago. Eventually I got my angles to a point where the vibration was resolved. however here are there responses:

Q: I understand that The Driveshaft Shop has, on occasion, made cv driveshafts (using rzeppa joints) for older muscle cars. I have a few questions
>
> Are the cv joints used on both ends of the shaft?
> If used on only one side, what angle does the pinion need to be at? Is it similar to a double cardan where you point the pinion at the transmission?
> How much heavier is the cv joint relative to a u-joint? Can common tailshafts like used on the tremec t56 handle the additional mass?
> Are knew slip yokes, with the appropriate flange provided? If on both ends of the shaft, is there a new pinion flange provided as well?
>

A: the angle issue wouldhave to be discussed in detail to give exact infor but for most
we would set the diff at 1 to 1.5 Degrees, the CV is a little heavier maybe 1 to 2 lbs
so its not going to be an issue and the fact that most we have done with a Aluminum shaft
takes it back out of the equasion (also the actual speed balancing takes it out) i have not
had to make then wioth CV's on both ends (for early cars) but can if the angles make it needed
as for the CV it not like a double cardan. its a true CV


to be honest this type of set up is more for a car that can not have the angles put in the proper set up for the
joints, i agree the double carded is poor choice. all it really does it kinda make it 2 small shafts splitting the
angle in half. you will still have a varying velocity joint (not constant like a true CV)

For what it's worth, I run my rear operating angle at -1 degree, so that under power, the pinion swings from the static -1 to about +1. I have fairly solid suspension bushings in the rear and I don't suspect that there is much pinion climb under power.

On my next build, I will definitely do the CV joint at both ends. That's really the optimal solution and it is what is done on all manner of modern cars.

Andrew

[Z06vet]

Andrew- what does a setup like you are running cost? I'll be doing a motor swap later this year. I'd rather use this CV shaft then cut/raise the tunnel since the car is finished. My engine/trans is at 3* down. My pinion is near zero- (after much trial & error this produced the best results)
Scott

[andrewb70]

Andrew- what does a setup like you are running cost? I'll be doing a motor swap later this year. I'd rather use this CV shaft then cut/raise the tunnel since the car is finished. My engine/trans is at 3* down. My pinion is near zero- (after much trial & error this produced the best results)
Scott

Scott,

The question is what is the angle of your driveshaft? Without knowing that, there is no way to determine the front and rear operating angles.

You've looking at about $1500 for a DS like mine. Keep in mind that the slip yoke has to be custom made.

Also, if anyone wants to do a CV at the rear and is running a Ford 9", you can get a CV pinion flange from Holinger Engineering.

Andrew

[Nothingface5384]

Still not the exact thread I'm trying to find but...
What about cv for s60 rear*

[andrewb70]

Still not the exact thread I'm trying to find but...
What about cv for s60 rear*

The particular set-up that is shown, uses a regular 1350 u-joint in the rear and a CV joint at the transmission. If you want a driveshaft with CVs at both the front and rear, then The DriveShaft shop has a solution. They have custom CV pinion yokes for 12 bolts, 9" and I do believe S60 rears.

Andrew

[TheJDMan]

Andrew,
I was wondering how your car drives after installing this DS. Did it resolve your vibration issues?

Steve

[andrewb70]

Andrew,
I was wondering how your car drives after installing this DS. Did it resolve your vibration issues?

Steve

Steve,

The CV driveshaft definitely solved my problems. However, before you spend the money make sure that you have eliminated every other possible source of high speed vibration. I have found that pinion yokes and gears tend to be a source of run-out, but as long as those are good, and you are finding that your front and rear working angles are more than 3 degrees, than you should consider a CV driveshaft.

Andrew

[Auto Rod Technologies]

I spent part of my day at a shaft shop today, but I didn't see anything like this,, interesting.

[andrewb70]

I spent part of my day at a shaft shop today, but I didn't see anything like this,, interesting.

You won't see this at your typical drive shaft shop...only at The Drive Shaft Shop!

Andrew

[gmorris]

I'm running one similar to Andrew's now as well, AL shaft with cv in the front. It helped my vibe but didn't eliminate it. I'm now going through pinion yoke and rear (which I should have done before but the shaft got rid of about half so it had to be done anyway).

[TheJDMan]

My 9" center section was a surplus NASCAR unit purchased from Roush Racing. It is equipped with a billet steel pinion yoke so I'm reasonably certain it is running true. I have tried reindexing my DS 180 deg in the pinion yoke but that had no effect on the vibration. The main issue I have is that my front u-joint has a working angle of 4 deg and I have no further adjustment available to decrease that angle.

I called the Drive Shaft Shop this afternoon to visit with them about ordering a CV shaft. The guy I spoke with was apparently not their drive shaft expert and he simply took my contact info and said he would have someone call me back. I hope to hear from them soon.

[andrewb70]

My 9" center section was a surplus NASCAR unit purchased from Roush Racing. It is equipped with a billet steel pinion yoke so I'm reasonably certain it is running true. I have tried reindexing my DS 180 deg in the pinion yoke but that had no effect on the vibration. The main issue I have is that my front u-joint has a working angle of 4 deg and I have no further adjustment available to decrease that angle.

I called the Drive Shaft Shop this afternoon to visit with them about ordering a CV shaft. The guy I spoke with was apparently not their drive shaft expert and he simply took my contact info and said he would have someone call me back. I hope to hear from them soon.

Steve,

4 degrees is right at the edge of being OK. There is a great chart posted on the Mark Williams website that plots working angle against driveshaft speed. Basically you want working angles of less than 3 degrees...the smaller the better.

When you call the DSS talk to Frank. He is the owner and he knows his stuff. Tell him Andrew sent you. They also have CV pinion yokes now so you can get a true dual CV shaft made, which is what I would do if I had to do mine again.

Andrew

[TheJDMan]

Update.
Well I spent some time yesterday just measuring and looking things over. I checked the runout of the DS and found the front had .004 and the rear had .035. I could not imagine what would cause .035 so I started measuring other components. Removed the DS and could not find any measurable runout on the pinion yoke which would have surprised me since it is a billet yoke. I reinstalled the DS 180deg and still got .035 runout on the DS. As I'm standing there looking at the rear u-joint assy I tripped on something on the floor and grabbed the DS to keep from falling(the car is on my four post lift). Anyway, I felt movement in the ujoint and started looking closer. Turns out that I could feel and see play in the actual ujoint. After a quick trip to the local NAPA to pickup a heavyduty 1350 joint I removed the old joint from the DS. What I found surprised me. The Spicer joints have a thrust washer inside the bearing caps and one of those thrust washers was missing from one of the bearing caps. Since the DS was ordered new a year ago from a well known vendor with the joints already installed the thrust washer must have been left out during the DS assembly. Anyway the new u-joint cleared up 90% of my vibration. So after nearly a year chasing this vibration it comes down to an incorrectly installed u-joint. I have adjusted the rear end so far trying to chase this that I have it all out of whack. I think now I just need to rotate my pinon back down where it was to start with and I should be able to clear up the last 10%. I guess the moral of this is to check everything and don't assume anything.

[andrewb70]

Update.
Well I spent some time yesterday just measuring and looking things over. I checked the runout of the DS and found the front had .004 and the rear had .035. I could not imagine what would cause .035 so I started measuring other components. Removed the DS and could not find any measurable runout on the pinion yoke which would have surprised me since it is a billet yoke. I reinstalled the DS 180deg and still got .035 runout on the DS. As I'm standing there looking at the rear u-joint assy I tripped on something on the floor and grabbed the DS to keep from falling(the car is on my four post lift). Anyway, I felt movement in the ujoint and started looking closer. Turns out that I could feel and see play in the actual ujoint. After a quick trip to the local NAPA to pickup a heavyduty 1350 joint I removed the old joint from the DS. What I found surprised me. The Spicer joints have a thrust washer inside the bearing caps and one of those thrust washers was missing from one of the bearing caps. Since the DS was ordered new a year ago from a well known vendor with the joints already installed the thrust washer must have been left out during the DS assembly. Anyway the new u-joint cleared up 90% of my vibration. So after nearly a year chasing this vibration it comes down to an incorrectly installed u-joint. I have adjusted the rear end so far trying to chase this that I have it all out of whack. I think now I just need to rotate my pinon back down where it was to start with and I should be able to clear up the last 10%. I guess the moral of this is to check everything and don't assume anything.

Steve,

Thanks for the update. It is amazing how little things can cause such big headaches. This is why it is so important to check all the little things first, before jumping into a big investment like the CV driveshaft. This sort of driveshaft is not a "cure all" for vibration issues. It is a devices that solves a very particular situation, that being a front working angle that is more than 3-4 degrees. However, it will only help once all other components are verified to be in perfect working order.

Everyone has to start with the trans. T56s especially are known for some issues related to 5th and 6th gears. Then you have to check the tails haft bushing, the slip yoke, the front u-joint, the tube, the rear u-joint, the pinion yoke, pinion gear and pinion bearings. All of these components can introduce run-out and a combination of components can amplify the run-out. Only after everything is verified several times, should you start considering working angles and possibly a CV driveshaft should you find that the front working angle is too big.

Andrew

[TheJDMan]

I spent several days adjusting the rear end pinion angle throughout my available adjustment range and I cannot clear up the remaining vibration at the current ride height. Adjusting the pinion angle had no effect on the front u-joint working angle so in theory if I raise the rear ride height an inch or two it should bring my front u-joint working angle into range. Rather than adjust the springs I decided to block the body up in the air a bit and remove the wheels then let the rear end drop about 2". I put it in 6th and ran it up to speed at the vibration point and even with the drop in the rear suspension I still have the vibration so now I'm out of ideas. At this point I'm searching for a competent performance drive train shop that can help me trouble shoot this.

[Nicks67GTO]

Iv'e got the damnedest vibration. If I'm casual in 3rd gear I can barely feel it but it comes in fast if I hammer on it @ 3K RPM and higher in 3rd gear. Its lesser in 4th gear when getting on it and its gone in 5th at cruise or hard acceleration.....really weird stuff.