Daze

I decided that a coil over front end would be a nice complement to my IRS project and tubular UCA are needed to make the swap. I found a really inexpensive aftermarket tubular UCA that were designed for an “other” brand car and was able to reengineer it to fit 64.5-66 Mustang. The original unite was designed so that you could thread a heim joint in to the ends, and then mount it to the chassis. I wanted the unit to be adjustable so I fabricated tubes with LH thread on one end and RH thread on the other end, by welding two jam nuts LH and RH to the end of a piece of mechanical tubing and then threaded the tubing, then I shortened the UCA, threaded in some grade 8 all-thread and welded the all-thread in place. To make alignment adjustments, rather than using shims, all the alignment shop has to do is loosen the jam nuts lengthen the arms by turning the sleeve, and then tighten the jam nuts. I cut the shaft that connects the UCA to the shock tower 1/8” short that way 4 individual 1/32” shims can be used on either side to center the shaft or offset it by 1/32” 1/16” or 1/8” to increase caster. I also welded the original ball joint holes closed and drilled new ones for the 4-bolt ball joint. I know it looks a little rough, but I am almost out of welding gas didn’t have time to clean up the welds, and like I said it is a prototype. Please let me know what you think, and or any changes I should make.

JMD

I will have to admit to not reading everything you wrote above because all of the text would not fit on my window at the same time, I did skim over it.... (is this guy lazy or what?? )
But they look absolutly bitchin..... Damn good job Daze..... They are awsome.

Starfury

Kinda remind me of the TCP UCA's.

First note, the points where the outer part of the arm meets the nut look weak (granted, I can't see them that well). I'd be kinda afraid of these points stress-cracking, especially since you've done some welding on them. Did you heat treat them? Also, if that plate you've got the ball joint mounted on isn't welded through completely, I'd be afraid ofit shearing off.

Second note, I'd want to compare the length on of the arm from the fender to the ball joint with a stock arm (and ideally Global West and TCP arms) and see what you come up with. The Global West arms are shorter for a steeper camber curve, and the TCP arms are nice in that they're adjustable like yours, so in addition to changing caster you can also change the camber curve.

Third, how's the ball joint angle compared to stock? A little bit of an angle there would help prevent binding with a control arm drop (which I'd consider mandatory with this kind of upgrade).

Fourth...where's the coil spring saddle mount? You'd need a coilover system to use this control arm as-is.

Please don't take any of this personally. I love the stuff you're doing and hope you keep at it, I'm just providing some constructive criticism.

Mr. Classic EFI

Daze how hard to "adjust" the angle of the ball joint mount, so's to do a deeper UCA drop?
May as well go whole hog!

Daze

Not taken personally at all, in fact the reason I post projects like this is to get "constructive criticism". Now it is my turn for the "qualifying statement" Please don't take what I am about to say as argument, I will simply address your concerns and I would still appreciate your comments on these points after I have explained further.

Before starting this project I took a good look at what the aftermarket was selling so yes it is similar to TCP's products as well as many others.

The first point, are you talking about where the 5/8" grade 8 all thread is welded to the end of the tubular control arms?? If so I too was concerned about that joint being strong enough so the inside of the tubes were threaded with 5/8" fine thread about 3/4" deep. the studs were then threaded in and welded to hold them in place. Nothing has been heat-treated, I am not set up for that. As far as you talking about the ball joint plate, the UCAs were aftermarket tubular units that I modified so the welds holding the tubes to the plate were done at the factory. Here is an exploded view of the unit so you can see exactly what I did.



The length of the arms fully shortened is 9.5" from the center of the pivot shaft to the center of the ball joint. A stock UCA also measures 9.5" I figured sense the alignment normally "lengthens" the UCA with shims that starting at a stock length would be good. I will not be running more than -.05 camber so stock length will be IMHO sufficient.

The ball joint angle is parallel to the top of the UCA which is typical of a ball joint /UCA with the negative wedge kit installed or an Opentracker modified UCA. Once the unit is in the car I will take it through full range of motion to insure the ball joint does not bind in extreme situations.

Yep no spring saddle mounts because this arm is being designed so that I can build a coil over-set up. I look forward to hearing your further thoughts on this UCA


Already been incorporated in to the design

Norm Peterson

The worst loading these arms see is from braking, and that's a forward force in the plane of the arm. It puts the rod ends in bending, which is not ideal but may be OK if the rod ends are large enough. That fore/aft load also means that there can be no fore/aft motion of the rod ends, so you are probably in for shimming the ends of the cross shaft to less than 1/32". Any threaded lengths along the tube axes are also in bending, and the threads represent a stress intensification (about 2.3 times is what I would use for threaded connections for that kind of load in my job). Translation: if there's a choice of two sizes, go with the larger bolt size (and a fine thread is probably better than a coarse thread in the same nominal size since it leaves more metal cross section remaining).

Hard cornering loads the upper arm in tension on the more heavily loaded outside front corner, but the loads are probably still lower than those due to braking, and they do not introducebending in the arms themselves other than what the bends in the tubes cause.

Can I assume that the adjustment tubes are threaded to be ~75% full form threads, or are the welded-on jam nuts responsible for most of the thread strength development? Given the bending that exists, I don't think you want any loads trying to flex the nut. Not that the nut will actually bend measurably, but the shear force and its bending moment will try to wallow out the hole. Continuous, sound thread support inside the tubes would alleviate this.

Weld between the all-thread and the remainder of the original tubing -is the tubing Cr-Mo?Before welding, is the all-thread firmly positioned in the arm by the threading. I really don't like the idea of bending a small-diameter circumferential fillet weld when only the weld dimensions are resisting the flex, especially if it's Cr-Mo (postweld heat treatment of some sort is normally required, especially for something as mission-critical as suspension linkage).

Consider how much asymmetry due to build sloppiness or damage to existing chassis that you're willing to cover for by altering the lengths of the UCAs. As the arms become different in length, the geometry change over suspension travel is no longer the same, left vs right. IOW, the side with the shorter UCA will have 'faster' camber gain. And although it may not matter much, the geometric roll center will no longer remain on the vehicle centerline in pure two wheel 'bump' (it'll wander laterally a little). My suggestion here is to use UCA length adjustment in combination with normal shimming. Ideally, that lets you set the UCA lengths to both be equal to the shorter for whatever alignment spec you're trying to set, and the shimming under the cross shaft on the side that needs a longer UCA lets that side hit the same alignment setting without losing the UCA symmetry. A small amount I wouldn't worry about, but from working with a car that has something like 3/16" thicker shim packs on one side than on the other and has never been in an accident I don't think I'd be comfortable working with UCA length adjustment only given the amount of asymmetry that might be possible on a 40 year old unibody chassis.

You can also change caster by unequal adjustment of the tubes. But there may be a limit to how much caster adjustment you can get with the adjusters, as that changes the length between the rod end ball centers slightly. Most probably, this distance increases, so at least it will still fit. That may be something that can be worked out with shimming, though. Otherwise, simply tightening down the cross shaft end bolts will apply side loads and bending to the rod ends due to the bending stiffness of the UCA tubes.

All constructively intended.

On edit, looks like some of the above have already been addressed.


Norm

Starfury

Ah, I didn't realize the all-thread was threaded into the tubes. That helps, although I'd think maybe cutting a small rectangular section out of the tube along the internal thread length and filling that in over the all-thread might be more stable. And, as Norm mentioned,I'd try to figure out what kind of metal it is so you can properly heat treat it. It shouldn't take anything more than a decent oxy-acetylene torch.

Since you're planning on designing a coil-over setup, why not design a LCA with camber adjustments (like 67+)? That way you can actually shorten the minimum length of the UCA for a steeper camber curve and not worry about shimming anything to account for static camber. Then you can adjust the UCA out if you want to return it to a more factory camber curve.

valley firearms

This is all very interesting to me. Although when this subject comes up it's like listenening to people speak in different languages. I am trying to learn about this as I'm sure many of the others are. I do however have a mechanical background. I have looked at the arm and feel it may have a weak link also. The outside dia of the rod is smaller than the inside dia of the tube(unless the wall of the tube is thicker than it appears). Therefore the rod is not threaded into the tube. What if you were to run the rod the full length of the tub and reinforce it at both ends? If it were weakened by heat(weld) then it could be heat treated as mentioned earlier. Thanks and good luck.
[align=left] [/align]

[IMG]local://upfiles/21693/D08325767E5E4FB5826D8610806322A0.jpg[/IMG]

andrewmp6

clean the welds up a tiny bit some paint or powder coat they will look great

Daze

I really appreciate the input. tubing on the UCA is threaded and came from the factory that way, so the 5/8" grade 8 all thread actually threads in to the tubing by about 3/4" and is then welded in to place. I though about drilling a plug weld hole in the tubing near the inside end of the all-thred however I was worried that such a hole would actually weaken the UCA, and was not really nessisary sense the stud is screwed in prior to bing weleded in to place, I guess we will see when I make the next one. All input is appreciated and welcomed