Adjustable upper control arm opinions.

[tcanin00]

I've posted this other places but should have added it here too. These adjustable UCA's took the avatar from being able to make a full pass at the track maybe about 60% of the time to a car that goes dead straight eery time. They solved a serious lack of positive caster problem for me.

Little wheelies and almost 120 mph passes - I don't have to think or worry about these parts that have been on the car for over 2-1/2 years. They've seen more street driving too than you'd expect from a car like this (another 50 mile round trip to a cruise coming up this weekend!) I have not had any of the jam nuts come loose and the parts look like the day I put them on. Would I do them again from Peter? 100% ABSOLUTELY!!
View attachment 1716474722
Note that the avatar (72 Demon) has the 73+ front disc brake setup.

Thank you for letting me know how they're working for you. I think the lack of caster on wide tires is why my car feels as disconnected as it does.

 

[go-fish]

This, 1.03” bars, 225/60-15, Hellwig sway bar, Borgeson , and QA1 LCA’s. Daily driver and a pleasure to handle.
The next Duster will be the same recipe except bigger t-bars and double adjustable Fox’s.

 

[Kern Dog]

I've seen those lower control arms before. They don't seem nearly as robust as the factory arms.

 

[RedFish]

Inquiring minds, I have to ask,
What do yall do with the factories ecentric adjustments? I have a train of thought concerning the guy doing the alignment but 1 thing at a time.

 

[tcanin00]

This, 1.03” bars, 225/60-15, Hellwig sway bar, Borgeson , and QA1 LCA’s. Daily driver and a pleasure to handle.
The next Duster will be the same recipe except bigger t-bars and double adjustable Fox’s.
View attachment 1716474908

Good looking set up. And to be honest, the 1.08" torsion bars are on harsh side going from whatever the stock V8 bars were. I might go down a size or two in diameter and sell what I have.

 

[72bluNblu]

I've seen those lower control arms before. They don't seem nearly as robust as the factory arms.

Quite the opposite. I've had the QA1 LCA's on my Duster the same amount of time as the SPC uppers. Their tubular design makes them substantially stronger than the factory ones.

Mopar Action did a comparison on them, the factory LCA's and the Firm Feel modified 73/74 B-body LCA's in an article from April 2011. At the time the tubular LCA's were being made by CAP, and even those managed to be substantially stronger than a factory set of LCA's. Must have had a set from CAP with good welds. Anyway, QA1 bought out CAP and improved on the design further, as well as of course improving the manufacturing process that CAP clearly had issues with. Anyway, the relevant excerpt from the 4/11 Mopar Action article-

I did have a set of the CAP made LCA's on my Challenger, IIRC they made it about 50k miles before I had a weld fail. Much like the test they did the tubular part of the LCA pulled away from the box they use for the adjusting lever housing. So I noticed the car sitting lower on one side, nothing else. Having compared the CAP made tubular LCA's side by side with the QA1's, I'm not at all concerned about the QA1's. CAP had manufacturing issues with cold welds.

Inquiring minds, I have to ask,
What do yall do with the factories ecentric adjustments? I have a train of thought concerning the guy doing the alignment but 1 thing at a time.

I just set my factory eccentric bolts in the middle. I should probably do a suspension geometry work up comparing the furthest in and furthest out settings since that would change the length of the UCA, and the SPC's are more than adjustable enough to manage that change and still be capable of setting the static alignment numbers I'd want. I'm sure it wouldn't be a huge difference, but even a small change there can improve the dynamic geometry.

 

[tcanin00]

Quite the opposite. I've had the QA1 LCA's on my Duster the same amount of time as the SPC uppers. Their tubular design makes them substantially stronger than the factory ones.

Mopar Action did a comparison on them, the factory LCA's and the Firm Feel modified 73/74 B-body LCA's in an article from April 2011. At the time the tubular LCA's were being made by CAP, and even those managed to be substantially stronger than a factory set of LCA's. Must have had a set from CAP with good welds. Anyway, QA1 bought out CAP and improved on the design further, as well as of course improving the manufacturing process that CAP clearly had issues with. Anyway, the relevant excerpt from the 4/11 Mopar Action article-

View attachment 1716474979

I did have a set of the CAP made LCA's on my Challenger, IIRC they made it about 50k miles before I had a weld fail. Much like the test they did the tubular part of the LCA pulled away from the box they use for the adjusting lever housing. So I noticed the car sitting lower on one side, nothing else. Having compared the CAP made tubular LCA's side by side with the QA1's, I'm not at all concerned about the QA1's. CAP had manufacturing issues with cold welds.


I just set my factory eccentric bolts in the middle. I should probably do a suspension geometry work up comparing the furthest in and furthest out settings since that would change the length of the UCA, and the SPC's are more than adjustable enough to manage that change and still be capable of setting the static alignment numbers I'd want. I'm sure it wouldn't be a huge difference, but even a small change there can improve the dynamic geometry.

I would need to get the QA1 LCA's if I want to run a sway bar with their tubular K member. The mount locations and QA1 sway bar is completely different than stock A body bars. Their LCA's look to be a decent product and i have not heard anything negative about them. I know the tubular K member is well made and it makes working on the car a little easier.
That is an interesting point about where to set the bolts for an adjustable UCA. I know the length, if even +/- 1/2", will effect camber and caster. I would think they should be at one end or the other of travel so that they would be in line with each other, but that is just my opinion without reading the instructions.

 

[72bluNblu]

I would need to get the QA1 LCA's if I want to run a sway bar with their tubular K member. The mount locations and QA1 sway bar is completely different than stock A body bars. Their LCA's look to be a decent product and i have not heard anything negative about them. I know the tubular K member is well made and it makes working on the car a little easier.

So the sway bar tab on the QA1 LCA's is almost exactly in the same spot at the sway bar tab on the stock 73+ LCA's. I have a Hellwig 55905 (73+) sway bar on my Duster and was running it with factory LCA's with the 73+ sway bar tab locations when I switched to the QA1 LCA's. All I needed to do for the switch was shorten the end links. The horizontal location of the QA1 tabs is basically the same as the 73+ tabs, but because the height profile of the QA1's is shorter the tab is in a different vertical location, so the end link needed to be a little shorter.

So if you currently have a set of factory LCA's without sway bar tabs, you could just get the weld on kind and add them in what would amount to the 73+ sway bar tab location.

My car with the 73+ Hellwig bar and the 73+ factory LCA's with factory tabs

With the same sway bar and the QA1 LCA's

That is an interesting point about where to set the bolts for an adjustable UCA. I know the length, if even +/- 1/2", will effect camber and caster. I would think they should be at one end or the other of travel so that they would be in line with each other, but that is just my opinion without reading the instructions.

I have mine in line with each other, I just put them in the middle. I used the eccentric washer location to make sure they were in the same spot.

The UCA works fine even when they're set to opposite adjustments though, that's how you set a factory UCA for maximum caster- front adjuster all the way out, rear adjuster all the way in. For the static adjustment with the SPC's it wouldn't matter, there's enough adjustment there to get the static right regardless of how you set the eccentrics. But it would have an effect on the dynamic numbers because it would be changing the length of the UCA and the location of the UCA pivot points.

But you'd have to plot the geometry out yourself based on the measurements of the UCA pivot locations and upper ball joint location.

 

[tcanin00]

So the sway bar tab on the QA1 LCA's is almost exactly in the same spot at the sway bar tab on the stock 73+ LCA's. I have a Hellwig 55905 (73+) sway bar on my Duster and was running it with factory LCA's with the 73+ sway bar tab locations when I switched to the QA1 LCA's. All I needed to do for the switch was shorten the end links. The horizontal location of the QA1 tabs is basically the same as the 73+ tabs, but because the height profile of the QA1's is shorter the tab is in a different vertical location, so the end link needed to be a little shorter.

So if you currently have a set of factory LCA's without sway bar tabs, you could just get the weld on kind and add them in what would amount to the 73+ sway bar tab location.

My car with the 73+ Hellwig bar and the 73+ factory LCA's with factory tabs

With the same sway bar and the QA1 LCA's

I have mine in line with each other, I just put them in the middle. I used the eccentric washer location to make sure they were in the same spot.

The UCA works fine even when they're set to opposite adjustments though, that's how you set a factory UCA for maximum caster- front adjuster all the way out, rear adjuster all the way in. For the static adjustment with the SPC's it wouldn't matter, there's enough adjustment there to get the static right regardless of how you set the eccentrics. But it would have an effect on the dynamic numbers because it would be changing the length of the UCA and the location of the UCA pivot points.

But you'd have to plot the geometry out yourself based on the measurements of the UCA pivot locations and upper ball joint location.

Sorry for the delayed response, but the problem with a stock front sway bar and the tubular K member isn't the LCA's, it's because the tubular K member has different dimensions compartment to the stock K member. So I would have to use QA1's sway bar that is made for their K member.

 

[tcanin00]

The reason I don't have good alignment numbers yet is that I bought a Longacre alignment gauge cheap, and don't feel like paying $85 for the adapter that threads onto the end of the spindle. I'm in the process of making the part. Once I get it done, and some time to mess with it, I'll get actual numbers of where it's at now.

 

[72bluNblu]

Sorry for the delayed response, but the problem with a stock front sway bar and the tubular K member isn't the LCA's, it's because the tubular K member has different dimensions compartment to the stock K member. So I would have to use QA1's sway bar that is made for their K member.

Yeah I get it, I’m just saying that you don’t need QA1’s LCA’s to use the QA1 sway bar. You can weld tabs onto your current factory LCA’s in the factory 73+ location, or use 73+ factory LCA’s with stock sway bar tabs.

The reason I don't have good alignment numbers yet is that I bought a Longacre alignment gauge cheap, and don't feel like paying $85 for the adapter that threads onto the end of the spindle. I'm in the process of making the part. Once I get it done, and some time to mess with it, I'll get actual numbers of where it's at now.View attachment 1716475499

Nice! An adapter like that would definitely make using a magnetic gauge a bunch easier.

 

[tcanin00]

Yeah I get it, I’m just saying that you don’t need QA1’s LCA’s to use the QA1 sway bar. You can weld tabs onto your current factory LCA’s in the factory 73+ location, or use 73+ factory LCA’s with stock sway bar tabs.



Nice! An adapter like that would definitely make using a magnetic gauge a bunch easier.

I understood what you were saying about welding the sway bar tabs on the LCA's. That's something I'll worry about later.
I am thankful be to have worked at a machine shop and be taught be guys with a lot of knowledge, experience, and patience because I am unteachable. Now I work in shop that maintains the buildings of the State Capital, and I still get to make parts.

 

[tcanin00]

Well, it took longer than I thought to get accurate alignment numbers.
Left Right
Caster +6.5 +6.0
Camber -.75 +.50

This is how the car is now with the UCA eccentrics cranked all the way in on both sides. I did not check toe in. To be honest, I have an old Dunlop optical alignment set and didn't feel like messing with it.
I didn't expect the caster to be this close from side to side. I think as of now, it's more of a problem with the car itself and not the UCA's.

The adapter turned out pretty good, pun intended.

Now I can thread it onto the spindle.

 

[autoxcuda]

Well, it took longer than I thought to get accurate alignment numbers.
Left Right
Caster +6.5 +6.0
Camber -.75 +.50

This is how the car is now with the UCA eccentrics cranked all the way in on both sides. I did not check toe in. To be honest, I have an old Dunlop optical alignment set and didn't feel like messing with it.
I didn't expect the caster to be this close from side to side. I think as of now, it's more of a problem with the car itself and not the UCA's.
View attachment 1716478098 The adapter turned out pretty good, pun intended.

View attachment 1716478100
Now I can thread it onto the spindle.

That looks like a pretty decent starting point. You just need to finish the alignment.

Get the right side camber to -.5 deg for aggressive/autox driving. Then even out the caster.

Just a WAG, you’ll probably end up with 3-4 deg positive caster. Nothing wrong with that. UCA’s did thier job. You have regular UCA bushing right? Not offset?

Then finish the job with toe-in adjustments

And then double check everything and tighten everything and cotter pins when possible.

 

[tcanin00]

That looks like a pretty decent starting point. You just need to finish the alignment.

Get the right side camber to -.5 deg for aggressive/autox driving. Then even out the caster.

Just a WAG, you’ll probably end up with 3-4 deg positive caster. Nothing wrong with that. UCA’s did thier job. You have regular UCA bushing right? Not offset?

Then finish the job with toe-in adjustments

And then double check everything and tighten everything and cotter pins when possible.

Yeah, it's not as bad as I thought it would be. The problem is that the right side UCA is out of adjustment. I have heard of guys using shims on the bolts between the knuckle and lower ball joint to get the camber where they want it.
The UCA's have solid aluminum bushings and I don't think they're same diameter as stock upper arms, so they are not ofset.
I might make some new bushings out of acetal/delrin if needed.

 

[autoxcuda]

Yeah, it's not as bad as I thought it would be. The problem is that the right side UCA is out of adjustment. I have heard of guys using shims on the bolts between the knuckle and lower ball joint to get the camber where they want it.
The UCA's have solid aluminum bushings and I don't think they're same diameter as stock upper arms, so they are not ofset.
I might make some new bushings out of acetal/delrin if needed.

Ok. You need to work on it and put it in adjustment.

Both sides need to match. So if the right side only can get 4 degrees of caster with -0.5 deg camber… then left side will need adjustments to match.

It’s a lot of going back and forth

 

[72bluNblu]

Well, it took longer than I thought to get accurate alignment numbers.
Left Right
Caster +6.5 +6.0
Camber -.75 +.50

This is how the car is now with the UCA eccentrics cranked all the way in on both sides. I did not check toe in. To be honest, I have an old Dunlop optical alignment set and didn't feel like messing with it.
I didn't expect the caster to be this close from side to side. I think as of now, it's more of a problem with the car itself and not the UCA's.
View attachment 1716478098 The adapter turned out pretty good, pun intended.

View attachment 1716478100
Now I can thread it onto the spindle.

So the eccentrics are adjusted all the way in and you still have positive camber?

If that’s the case then shimming the lower ball joint to push the bottom of the spindle out would be your only option. But that would also suggest something is wrong with the chassis or the UCA.

Ok. You need to work on it and put it in adjustment.

Both sides need to match. So if the right side only can get 4 degrees of caster with -0.5 deg camber… then left side will need adjustments to match.

It’s a lot of going back and forth

Sounds like he’s all the way in on the eccentrics already, which would mean he’s got no way to add negative camber on the right side that’s +0.5.

 

[DionR]

Might be a moot point now, but BAC discontinued the SPC 1.0 and 1.5 arms a little while ago. Only the forged 2.0 arms now.

 

[autoxcuda]

So the eccentrics are adjusted all the way in and you still have positive camber?

If that’s the case then shimming the lower ball joint to push the bottom of the spindle out would be your only option. But that would also suggest something is wrong with the chassis or the UCA.



Sounds like he’s all the way in on the eccentrics already, which would mean he’s got no way to add negative camber on the right side that’s +0.5.

Ok missed that BOTH front and rear were all the way in. Yep, LBJ spacer could work.

Bummer.

IF it was just the rear that was in, you could pull the front in, get less caster, then reduce the caster in other side to match.

 

[tcanin00]

So the eccentrics are adjusted all the way in and you still have positive camber?

If that’s the case then shimming the lower ball joint to push the bottom of the spindle out would be your only option. But that would also suggest something is wrong with the chassis or the UCA.



Sounds like he’s all the way in on the eccentrics already, which would mean he’s got no way to add negative camber on the right side that’s +0.5.

Yes, the eccentrics are all the way in and it has positive camber. I would believe it's an issue with the car itself. I know these were high production/low quality cars with tolerances of Monday through Friday.
I'll have to do the math to figure out how thick of a spacer I need to correct the camber.

 

[tcanin00]

Might be a moot point now, but BAC discontinued the SPC 1.0 and 1.5 arms a little while ago. Only the forged 2.0 arms now.

Of course they are. It never fails that when I take so long to decide what parts I want to get, they become extinct and the new version is what's available.

 

[tcanin00]

Ok missed that BOTH front and rear were all the way in. Yep, LBJ spacer could work.

Bummer.

IF it was just the rear that was in, you could pull the front in, get less caster, then reduce the caster in other side to match.

Yes, front and rear eccentrics are all the way in. I started with the front eccentric out, but had about 3* positive camber.

 

[Demonx2]

Of course they are. It never fails that when I take so long to decide what parts I want to get, they become extinct and the new version is what's available.

I believe the 1.0's are still available elsewhere, just not from Peter. The bad would be that the ones Peter sold came with the Delrin and zerk fittings. I don't think ones purchased elsewhere have that.

 

[72bluNblu]

Yes, the eccentrics are all the way in and it has positive camber. I would believe it's an issue with the car itself. I know these were high production/low quality cars with tolerances of Monday through Friday.
I'll have to do the math to figure out how thick of a spacer I need to correct the camber.

I’d figure out why that right side is so far out. +3° to +.5° is more than just bad production tolerances.

@Kern Dog made a point about a right side PST UCA that was jigged incorrectly, might not be coincidence that your right side is also the one that’s off

I believe the 1.0's are still available elsewhere, just not from Peter. The bad would be that the ones Peter sold came with the Delrin and zerk fittings. I don't think ones purchased elsewhere have that.

Yeah there are SPC genI’s around still, I think SPC has discontinued them so you’re looking at who still has stock on the shelf.

Believe you’re correct about the bushings and zerks too.

The Gen II’s are very nice, but they are pricey.

 

[Kern Dog]

The 68 Dart that belonged to a friend was here for an engine build and suspension refresh. The owner bought PST tubular UCAs. The driver side aligned fine, the right side did not. We put the stock UCA back in and it aligned fine. I can't see how to blame anything except the PST part.