I was wondering what driveshafts most of you are running on your stock spring SOA, reverse shackle scouts. I am thinking of running a cv shaft out of a F*rd truck, but I am not sure if I have the room with the 727. Does the flange from the f*rd transfercase bolt to the front of the Dana 20 in the scout, or is there another part number for that? Will it have enough travel for the reverse shackle?

Thanks,

Maybe I'm wrong, and I've never done this. But I've seen CV joints on caddys a lot.

Can't you just delete the "Flange" and run the FIRST (closest to the transfer case) CV U-joint directly to the Fixed yolk on the D20?? Even if you had to get a DUAL SIZED joint.

Caddys have the CV's first joint going directly to the "Slip shaft" there's no flange on those.



BTW.......WELCOME NEWBIE!!!! :flipoff2: :flipoff2: :flipoff2: :flipoff2: :flipoff2: :flipoff2: :usa:

CV on 727 (http://www.gryphinracing.com/myths.html)

You'll have to cut the 727 pan some.. follow the link..

Thanks for the pics TSM1MT, that's what I was talking about.

BUT.....why not just put the CV on the axle end??? same effect isn't it??:confused:

Originally posted by Cliffhanger
Thanks for the pics TSM1MT, that's what I was talking about.

BUT.....why not just put the CV on the axle end??? same effect isn't it??:confused:


NO!!!!!!

It's not at all the same effect. Having a standard u-joint at top operating at an angle will introduce a harmonic oscillation to the angular velocity of the driveshaft, which the double cardan at the pinion end would be unable to remove. The reason the double cardan end goes at the t-case is because that is where the angle between yoke and driveshaft is. The double cardan maintains uniform angular velocity through the angle.

IT needs to go up top. Just trim the flange like Tom's pics probably show....

Originally posted by Bindernut



NO!!!!!!
The reason the double cardan end goes at the t-case is because that is where the angle between yoke and driveshaft is. The double cardan maintains uniform angular velocity through the angle.

IT needs to go up top. Just trim the flange like Tom's pics probably show....

Oh, I see. Thanks for clearing that up for me.

I'm running a CV in the rear of my scout. just had it added to the stock driveshaft. You will have to change the yokes on the D20 in order for the CV to work. I think they are around $35 or so. You can see a pic of it at the link below.Scout II pics (http://chevysetc.com/corn.html )

Originally posted by Bindernut



NO!!!!!!

It's not at all the same effect. Having a standard u-joint at top operating at an angle will introduce a harmonic oscillation to the angular velocity of the driveshaft, which the double cardan at the pinion end would be unable to remove. The reason the double cardan end goes at the t-case is because that is where the angle between yoke and driveshaft is. The double cardan maintains uniform angular velocity through the angle.

IT needs to go up top. Just trim the flange like Tom's pics probably show....


You know what, I keep letting it slide, but I can't take it anymore. I even gloss over it so that I don't have to explain myself, but it's driving me nuts. Double cardan joints don't actually maintain uniform angular velocity through them, they just get a hell of a lot closer to it than normal u-joints. Without any further explanation, this is because the following is true:

cos(theta) > [cos(theta/2)*cos(theta/2)]

That's also why in a pure math sense, you need to point the pinion slightly lower than straight with the driveshaft, not exactly in line with it. In the real world, it doesn't really matter that much, but that's the way it *ought* to be, anyway.

I'm sure this will bother some people and confuse still others. Flame away, I can defend myself if anybody is familiar with multi-variable vector calculus as applied to mechanical dynamics.

Sean