Need help with Chenowth rear IRS

[regnad]

Hello all, looking for help identifying, and correction as needed. I have a Cenowth rail with bus tranny, IRS with Zcar half shafts and I'm told bus wheel hubs. I have determined that the z car has shafts are not long enough to satisfy the trailing arm length/width. Since I've had it I have had negative camber and killed my tires. Toed out as well.
I dove into it last weekend and disconnected the torsion bars influence on my spring plate allowing me to articulate the wheel travel. I just barely get close to zero camber by raising the rear end but I reach the extension limits of the z car shafts. As you can see from the pics, there is a plate welded to the stubs to shorten the distance and provide 4 hole bolt pattern.

My questions are:
1 how do you determine the needed cv axle length?
2 do cv axles compress and extend like the z car half shafts?
3 am I off track with my diagnosis?

[Casting Timmy]

You have something there, I would try and get measurements of the short and long of it (hahaha), but you'll have to figure out dimensions and see what it is. I saw a lot of units come in for rebuild where you could see the axles had hit the flange seal on the transaxle.

You can probably search how wide and long your arms are and find someone else and see how close you are to it. In the end little adjustments can make minor differences.

[Ol'fogasaurus]

Maybe this will help... or maybe not: https://www.pacificcustoms.com/ac525201.html

Not sure what you have in the pix.

I've done the VW bug IRS to Bus IRS a couple of times but I don't remember the dimensions. The Bus CVs are larger in Dia. so the drive flanges off a bus and the stub axle off a bus are also required besides the longer drive axles.

Lee

[jsturtlebuggy]

What you have there from what I can see is, are trailing arms made to use the cast steel bearing housings from a 1968 and later VW Bus. The stub axles are Bus that have been modified for the Datsun axles and the inner flanges also have been modified for the Datsun axles.
To go back to CV axles and CV joints your are going to need both the inner flanges and outer stub axles.
Since you going to have to have start out with new or used parts, you might think about going to Porsche 930 size CV joints and axles as price is not much different the using VW Bus parts. The 930 CVs allow for more angle and wheel travel then Bus.
The inner CV flanges to fit the Larger 930 CVs are available in the aftermarket. You have to get the Bus stub axles modified for the 930 CVs,
Don at DK Maching@Fabrication (562)864-9618 in Norwalk, CA modified stock stub axles to fit larger CV joints.

CV joins plunge and move back and forth on axle splines to take up differences in suspension travel.

To find out what axle length you need, line up both inner and out flanges so they are straight across. Then take measurement from cup part of flanges. Take reading and subtract a 1/4 to 1/2in and that will be axle length you need. With a Bus transaxle you may find different readings from side to side as centerline of transaxle is offset because of hypoid design. It will depend on how transaxle is mounted in chassis.
Aftermarket axles can be cut shorter and new groove cut for spiral lock to work if needing two different length axles are needed.
I am using Empi axles and CV joints on my own buggies with good results

[regnad]

Excellent thank you Joseph for the detail. If I have to spend money I'm going 930's.
What's the stock trailing arm length? Trying to determine length of mine...

[jsturtlebuggy]

The stock length of a trailing arm is 16-1/2in.
That measurement is taken from center of torsion bar to center of stub axle.
I don’t having any stock IRS suspension to give a measurement for track width.
Stock length CV axle is 16-1/4in.

[regnad]

Thanks again Joseph! Not sure if I can post a link, but is this kit what I am looking for with all needed parts? Once I determin length that is.

https://www.pacificcustoms.com/ac598232.html

[regnad]

Next question. Is there a typical downward angle of the axles for IRS buggies?

[jsturtlebuggy]

That 930 CV axle setup will not work for you with the rear trailing arms you have. Your setup is using Bus (Type 2) stub axles which are larger diameter then the type 1 stub axles that are in the kit.
From the pictures you have posted the disc brake setup is using the 1971 Bus hubs and Mercedes Benz brake rotors which both have a 112mm wheel stud spacing.
Todd Francis (Precision Alloy) the inventor of the TF1 aluminum VW engine case used to make a disc brake kit using the Mercedes Benz and VW parts. You could contact Todd and see if still making the kits.
With 930 CVs joints you get 24 degrees with them using a angle finder on the axle.
The blindchickenracing.com site may help with questions you have.

[regnad]

Does this resolve my issue?
https://www.pacificcustoms.com/ac525111-bus-s.html

[jsturtlebuggy]

Those stub axle look like the one that Todd Francis does at Precision alloy Ltd. At precision alloy.com
I would contact Todd for more information on them. He might even have a better price since he makes them.
Precision Alloy Ltd
25805 N. E. 46th Ave
Ridge field, WA 98642
Ph (360) 887-2000
Email: [email protected]
Precision alloy.com

[regnad]

Diving in to see what I need.

[regnad]

New concern. Will 930 cv joints clear frame?

[jsturtlebuggy]

I have a Chenowth like yours buggy that I bought a few weeks back that has 930s CV on it and they clear the frame tubing like yours in the pictures.
That is a very thick piece of steel on the inner flange. Does it unbolt from the CV flange? Or is it part of it?
To remove the inner flanges there is a snap ring under the rubber cap in the center of flange.

[regnad]

It looks like its part of it. So do I need to pop rubber cap off inside flange and needle in there to remove snap ring?
Lol that's gonna be difficult. I also need affirmation on measuring shaft length. I've seen the pics and directions bit need someone to point at the measuring planes.