Rear Sway Bar -n- Stuff

All,
I haven't gotten to posting pictures yet, but the Spence car had a bit of a setback last weekend. Our intent was to install the full rear end and get to a rolling chassis. Unfortunately, our rear end is a little out of 'alignment' and we have about 5/16" too much camber. Positive camber at that. While we wait for the revised half shafts, I am trying to solve another dilemma.

In narrowing the rear end, the sway bar does not fit between the outer carriers/hubs. I'm not talking a tight fit, the sway bar is literally wider than the space between the carriers.

Here's the question...Does anybody know if the FIA rear sway bar is different on a narrowed rear end? Can anybody post pics of their sway bar mounting linkage on a narrowed FIA suspension?

Help!

Unique 9122 - 289 FIA Cobra - The Legendary "Spence" Car

I think that the majority of Unique's out there do not actually have a rear sway bar mounted, only a front sway bar. Something to consider...

There is only one sway bar available from Unique.

Brian, you could contact Helwig and see if they will build you a one-off. You will have to provide engineering (no problem for you) and it will be costly as I went through the process for my modified front sway bar with them. I would not wait too long as they are usually in their slow time in Feb as I recall. It took a long time once they had the drawings and the original bar 'cause I was at the end of the line and all the normal production and tooling went first. It is a filler job for them. If I can be of any help let me know.

Ralph

I figured that Unique only has one available...So the question is, do they not spec them to FIA cars with Trigo wheels?

Unique 9122 - 289 FIA Cobra - The Legendary "Spence" Car

I think with any of the Unique cars with Trigo wheels they are not exactly the correct length. I know mine could be shorter so the adjustment rod to the rear end from the sway bar
would line up vertically. With the 289 FIA and 427 S/C with the various wheel configurations there would probably have to be 6 different sway bars for the rear.

Rick
#4279405

You can use 1/2" electrical conduit and pipe bender to produce a mock up of what you need then have it fabricated. Much better than drawings and way cheaper.

Randy

Unique 289 FIA #2899420
Southern Automotive 396
Team III 16's
Brilliant Silver

Brian,
I have been through the sway bar shuffle several times. When I first built mine in '93 I used the MGB 9/16" diameter bar in the front and no bar in the rear. Needless to say I was unhappy with the amount of body roll in the corners. I found a MGB 5/8" diameter bar in a scrap yard and installed that in the front and put the 9/16" in the rear.
I drilled the frame and welded in nuts for the mount to the body in the rear and made "links" with 1/2" male and 1/2" female heim joints threaded together with a jam nut.
After a few more years of being unhappy with the way it handled, I ordered three more sway bars to fit an MGB from WWW.MGOGaccessories.co.uk (1", 7/8" and a 3/4"). That summer I tried several combinations of bars and ended up with the 1" in the front and the 3/4" in the rear.
I am very happy with the way it handles now, there is almost no body roll or perceived weight shift even in the most severe corner.
Is your rear bar from an MGB? If I remember correctly the rear bar on mine does not even come close to the rear carriers and I believe I have a 56 inch flange to flange measurement.
If you want a photo of the rear links I made I can pull a wheel and get one this weekend, however, they are just two heim joints screwed together with a jam nut to lock them.
Keith

I put a sway bar off a dirt track car on mine. Put it inside the rear crossmember, bronze bushings with grease fittings. Then if I wanted to change to a different size it only took about 30 minutes.
Keith,
Your track width is the stardard length. The 2 heim joints put togeather is the way Unique does it.

Keith,
Poorboy is correct, the heim joint installation is how we connect to our sway bar. However, our flange to flange measurement on our rear end is just under 51", so we are significantly narrower than your car. The Trigo wheels necessitate the narrower setup. I think I will just need to contact a sway bar manufacturer and see if there is something that will fit off the shelf. We also may try to bend ours, but 3/4" steel is not going to give up all too easily.

Unique 9122 - 289 FIA Cobra - The Legendary "Spence" Car

Brian,
If you want to use the same sway bar you may be better off cutting out a section in the center then machining a sleeve about 8 to 10 inches long and doing four plug welds 90 degrees apart on each side.
The sway bar is spring steel so a continuous weld would put too much heat in it and loose the temper. The plug welds properly done, should not have a major effect on the heat treat condition of the steel. The sleeve will also make it "stiffer" as the sleeved section won't have the same twist ratio as the rest of the bar. But, it could be a low cost alternative.
I am not too sure if you will be able to "bend" the sway bar cold. I believe the grain structure of the steel would modify (break apart) if it was cold formed. It will bend with heat but then you would have to go back through a heat treat cycle again to bring back the "spring" properties.
Keith

Keith,
That's a great thought. I was thinking of bending the bar hot, but didn't consider the heat treatment needed. We'll definitely cut and sleeve it. Since we have the bar and the mounts already, this will be an easy fix. Thanks for the tip!

Unique 9122 - 289 FIA Cobra - The Legendary "Spence" Car

Keith, I did not know you could do that with spring steel and have it hold. I know if you tried to bend it it would mess the grain up or snap if not hot formed and heat treated in a soak furnace. Four evenly (at each 90 degree axis) spaced plug welds. Certainly a neat idea.

Ralph