Adjusting control arm heim joints

[Alex]

I don't understand how you're supposed to adjust the heim joints on the control arms. Obviously the rod end spins in/out, but how are you supposed to do it once the control arms are on the frame?

For example, you install your front UCAs. Torque everything up. Now down the road you're ready to set caster/camber. It can't be (a)unbolt UCA (b) spin heim end in/out (c) bolt back (d) check caster/camber (e) repeat a<->d until you get the correct number?


On FFR cars, the UCAs have tubes that can be spun while on the car to lengthen/shorten the arms. Makes sense.....can't figure out though with billet control arms how you're supposed to do it with them on the car. I've got billet LCAs on my cobra, and all I did was turn the heim joints on each arm out 3/4 turn before installing them and hope I got it right the first time (I guess I did).

I'm probably overlooking something (e.g., there are some set standards, like turn each one out 1 full turn and forget about it), but I don't know what........

 

[Chuck]

You wrote:

"For example, you install your front UCAs. Torque everything up. Now down the road you're ready to set caster/camber. It can't be (a)unbolt UCA (b) spin heim end in/out (c) bolt back (d) check caster/camber (e) repeat a<->d until you get the correct number?"

That is exacty how I did mine. By 'presetting' the heim's you can get it pretty close initially. If you need info on a GT I can oblige, although I suspect Fran and others may have already posted some guidelines.

Chuck

 

[Alex]

What do you mean by pre-setting the heim?

 

[Chuck]

I drafted a post, but never posted it. For what it is worth here is where my GT 40 front adjustments ended up:

Lower control arms: heims turned out 6 - 8 threads past the lock nut.

Upper control arms: discard the lock nut. Three threads exposed. When fine tuning the camber, make the adjustments on the top. It is a lot easier than on the bottom.

Hope this helps. I will post more info on my build blog shortly

 

[Phil]

Efinfast:
I think what Chuck means by pre-setting the rod ends is basically taking an educated guess based on measurements. I have found that billet wishbones look great, but are a pain in the ass to setup, the only good consideration is that you hopefully won't be doing it a lot.
I prefer an alloy wishbone (Chromoly) with threaded sleeves because of the ease of adjustment, and the resolution available. You can adjust in munute amounts, whereas on a threaded in rod end you need to go a 1/2 turn at a time. On large rod ends like a 3/4 thread this would mean 1/32", less on smaller units, but you are left with a compromise.
Probably on a street driven chassis this would not be an issue with slower speeds and more forgiving tires.
Just my 2c
Cheers
Phil

 

[Mike]

For example, you install your front UCAs. Torque everything up. Now down the road you're ready to set caster/camber. It can't be (a)unbolt UCA (b) spin heim end in/out (c) bolt back (d) check caster/camber (e) repeat a<->d until you get the correct number?

Well, you might think it's lame, but that is how it is done. Pretty much that way for any race car that doesn't use left/right threaded links. It may be a PITA to get adjusted right, but it is solid once it is done. As oposed to the FFR GTM that uses the stock Vette eccentric bolts and......well you can read all about the fun those are over on the FFCOBRA site. You must be talking about an FFR Cobra build?

 

[Mike]

I

Upper control arms: discard the lock nut. Three threads exposed. When fine tuning the camber, make the adjustments on the top. It is a lot easier than on the bottom.

IMHO, that is NOT a good idea. The motion from the suspension will work on those threads and could lead to eventual failure. At the least it will lead to inconsistent settings. Shift things around a little if you have to, but don't leave a rod end without a jam nut installed.

 

[Chuck]

IMHO, that is NOT a good idea. The motion from the suspension will work on those threads and could lead to eventual failure. At the least it will lead to inconsistent settings. Shift things around a little if you have to, but don't leave a rod end without a jam nut installed.

Thanks for the tip. Randy (Big Foot) also raised that issue. Last night took it apart and re did it, with the lock nuts on the heims back in place.

 

[Jac Mac]

The RCR UCA could possibly be altered to use a 'sleeve' nut as per the dwg below for those of you who spend a lot of time at different tracks & wish to make rapid adjustments. If the OD of the sleeve nut was kept to a sensible minimum there shouldnt be any major reduction in UCA strength, might pay to consult the cars designer on this mod first though.