Double Cardon rear shaft

[brad 93hilux]

Well one of the next projects I've got goin into my lux is a 80 series rear diff with all custom mounts and its going to get shaved.

What I want to do is to help with hitting my driveshaft on everything (I know it's not going to fix it) I want to cut down a 80 shaft and weld in on the transfer end a hilux flange and double Cardon joint.

From the reading I can find, a standard uni shaft the diff sits nearly parallel with the output shaft on the transfer but with a d/c rear shaft you can angle the pinion up at the transfer.

And if that's so how much higher can you go -ie point it above transfer flange?

What affect does it have?

I've read through http://www.pirate4x4.com/tech/billavist ... index.html" onclick="window.open(this.href);return false; and there is alot of great info but I just want someone with the experience..

Thanks brad

[-Scott-]

From the reading I can find, a standard uni shaft the diff sits nearly parallel with the output shaft on the transfer but with a d/c rear shaft you can angle the pinion up at the transfer flange.

Can someone tell me why a d/c joint allows you to do this.

I can't, but he probably could: http://en.wikipedia.org/wiki/Gerolamo_Cardano" onclick="window.open(this.href);return false;

OK - I'll have a crack, because I'm bored.

A single universal joint isn't a constant velocity joint. When the two shafts are not completely aligned the driven shaft's rotation speed varies slightly with respect to the driving shaft - it acceleraes and decelerates during each revolution. The amount of acceleration / deceleration varies according to the angular displacement.

Two universal joints in series, when the two angular displacements are equal, effectively compensate for this velocity cycling - the intermediate shaft still cycles velocity each rotation but the diff input keeps the same speed as the gearbox (transfer) output shaft.

A double cardan joint is effectively two uni joints in series, with an extraordinarily short intermediate shaft. It effectively splits the angle in two, so input and output keep a constant velocity. I'm guessing that, when a third uni joint is added to the system, the double cardan joint "self adjusts" so that any variance in the single uni joint is taken out by the double cardan.

At a guess.

[the gun]

Is it still a daily driver? If u rotate the pinion up to far, both the fr and rear uni angles will be opposite plane as each other and therefore will cause a vibration. They need to be in the same plane to function correctly, regardless if a cardonal is used the angles dont nessarily have to be equal, but must be in approximitly the same plane. Sort of touched on in the prevous post. Dont confuse all this with phasing the uni s as that is a related but different.

[brad 93hilux]

Yes it is driven on road, not daily but to/from tracks

Out of the pirate info I have read it said on a standard 2 uni shaft the joints must be in phase and equal angles top/bottom
On a DC shaft it does not say if its the same (in/out phase) so not sure on that.

Now apparently on a standard shaft the two uni's at the same angle means the vibrations each uni causes are cancelled out by each other.

In a dc shaft the dc joint/cv takes the main angle and cancels out the vibration itself, then you have the uni at the diff which needs to be set at O degrees or it causes vibration itself.

Pirate suggests setting pinion around -1 to -2 degrees between shaft and pinion (through lower uni) that way with axle wrap it comes back closer to 0.

I understand this but in reality how much misalignment would be acceptable for a road driven truck being it already has a heap of noises and vibrations (trep's or simex's)

I figured there will be a few with the knowledge as I would like to set it at a acceptable + degrees if possible, but feel fee to fill me in with if it 'HAS' to be 0.

Cheers
Brad

[the gun]

O degree is fine. And really if its only a weekend warrior doing minimal road miles the vibration from either an out of phase tail shaft or poor angles won't be to much of a problem. Yep centrepeds would hide the vibration very well. But a shaft with excessive runout etc will flog out the uni joints and transfer output bearing/pinion bearings sooner than later.

[brad 93hilux]

Has anyone had much to do with setting up a dc shaft that knows what degrees it was set up as?

Cheers brad

[80's_delirious]

Scott is on the money, (EDIT- so is your 2nd last post) DC cancels out its own vibes, but if the singl uni is not at zero, you reintroduce a source of vibration. The greater the angle of the single uni, the greater the vibration. With normal uni joints a couple of degrees variation is acceptable.

One thing to consider is the offset of the rear diff, hilux diff is centred isn't it?
If so, using an offset 80series diff and centred transfer output, it will mean your rear uni will always have some angle at the diff pinion. It may be zero degrees at the diff when viewed from the side, but it will be angled when viewed from the top. In this case, you will get vibration if you use a DC joint at the transfer.

[brad 93hilux]

Scott is on the money, (EDIT- so is your 2nd last post) DC cancels out its own vibes, but if the singl uni is not at zero, you reintroduce a source of vibration. The greater the angle of the single uni, the greater the vibration. With normal uni joints a couple of degrees variation is acceptable.

One thing to consider is the offset of the rear diff, hilux diff is centred isn't it?
If so, using an offset 80series diff and centred transfer output, it will mean your rear uni will always have some angle at the diff pinion. It may be zero degrees at the diff when viewed from the side, but it will be angled when viewed from the top. In this case, you will get vibration if you use a DC joint at the transfer.

Mmm.. Yeh I missed that, was only thinking in relation of the shaft and uni and not offset of diff and transfer.

Would be much better if I could angle it up at transfer.
Is there a reason you can't use a DC at either end? Or is putting it up the top more for keeping it out of harms way?

Any ideas how to best set this up? Or would it be more beneficial to just run longer stronger control arms and they can be used to slide over logs/Tyres and hopefully helping to protect tailshaft.

Brad

[80's_delirious]

Custom housing and axles maybe? That way you can centre the pumpkin, use a DC joint and angle the diff pinion up to the transfer.
Are you using 80series for the larger centre? Are 60-70 series diffs offset?

Or pootrol diff?

[brad 93hilux]

Don't want to go patrol, ill keep it all Toyota.

I already have the 80 diff, but reason is I run 37" sticky treps, i have a ifs rear diff and run 2" wheel spacers on the rear to clear them. A 80 series diff is approx the width of my rear with the spacers.

Although I got away with Toperi with lux gear I doubt it will last, so for the same width I get disk rear, floating axles and a much larger centre.

I was trying to have as much factory spares as possible to bring cost down/ ease of parts.

[brad 93hilux]

I climbed under the lux to have a look and think, and looking at the current setup I think I'm not going to achieve much from a DC shaft anyway. My rear is 1390 long and the uni's are not on much of an angle.

But such a long shaft it hangs down a fair bit.

I'm thinking a better setup will possibly be a 2 piece rear shaft with a centre bearing to make the angle steeper and holing it up as much as possible.

Is there much in the way of a aftermarket stronger centre bearings?

[80's_delirious]

Google pillow block bearings. No idea what one you'd need.