Positive Camber Impossible?
Great info guys. Still unsure if i am able to get my steering to return. I believe this means positive Caster (not camber as I mistakenly posted originally). So how can I get positive Caster? Is it possible? I have now replaced everything, and still the steering is loose. and no return after a turn. I want it to force its way back to the center, and keep that line until I steer. Possible? I am running 14in tires.
You really haven't posted enough information for a proper diagnosis. We don't know what your current alignment specs are, what size tires you're running other than that they're on 14" rims and based on your comments they're probably radials, what your ride height is, torsion bars, shocks, what's new, etc. Even with stock design bushings the car should be able to achieve positive caster. Not a lot, but +1.5* caster with the stock bushings shouldn't be impossible. More is better, but that usually takes Moog 7103 offset UCA bushings.
But, I don't think that's the problem you're having. If the steering will not return to center after a turn that's much more likely to be a problem with the steering box. Even with slightly negative caster the steering should return to center after a turn. Do you have manual or power steering? Has the steering box been rebuilt? Anything in the steering linkage changed with the rebuild?
RRR, perhaps you can give me the scientific explanation for this then: I'm running eccentric UCA's on my Valiant (installed correctly, NOT per the Moog instructions). It has P185/70/R13s on it, and with the LCA's jacked up too high by the alignment shop, they were able to get about 1.5 degrees of caster dialed into it, with about .5 negative camber. Like this, the car acted squirrlier than a Chip and Dale cartoon. Also pulls a bit to the right.
With P215/75/R14's on the front - without adjusting a single thing from the above - you could practically drive hands off. It would track dead center and turning left or right would result in the steering wheel coming back to center perfectly. Granted, the back of the car was now about 2" lower than previously, as the 13's were still in the back.
Since the 14's were only a test (those P215's were running on dangerously narrow 4.5" SBP rims), I put the original 13" wheels back on with the P185's, then dropped the LCA's down 2" since. It's still uncomfortable and pulls to the right a bit, but it's more controllable and predictable. I also get a bit more self-centering through tight turns, but not enough.
Perhaps a trail issue rather than than caster? Either way, I'm rather convinced the tire diameter is amplifying (or decreasing) some element of the suspension geometry, but I'm not going to rest until I know the exact science behind what's going on.
My bet is that more than a few of us may have a base-model A-body on factory 13's that would make for nice daily drivers/beaters as-is, but do not necessarily justify SBP 14" wheel swaps.
-Kurt
Every time you change the ride height of the front of the car with respect to the rear of the car the caster changes. In your case, if you lower the back of the car with respect to the front, you've added positive caster. Caster is just the tilt on the spindle. Positive caster means the top of the spindle is leaned toward the back of the car. So lowering the back of the car adds positive caster (assuming nothing else changed).
A 215/75/14 is 26.7" tall. A 185/70/13 is 23.2" tall. If your +1.5* of caster was with 185/70/13's all the way around, and you then added the 215/75/14's to the front only, you added a VERY significant amount of positive caster. It's not 1.5* anymore with that set up, regardless of you not changing your alignment. That's a 1.75" rubber rake to the back. Instant positive caster. Nothing in the front suspension changed, so, the camber, toe, everything else is the same. But the caster changed because the angle of the spindle changed with the rear drop.
When you lowered the front you changed all of your alignment specs. Everything. Caster, camber, toe, all of it. If you just consider the drop in ride height in the front compared to the rear you should have lost caster, but, because the suspension geometry itself changed the caster change isn't just based on the change in rake. You probably made some of the numbers better, which is why the handling feels better. But any significant change in ride height with the front adjusters requires a new alignment.
And then there's the pulling to the right. This could be a ton of things too, most of them mean your alignment shop isn't great. It could mean that they actually set the alignment specs exactly the same on both sides, which would cause the car to track slightly to the right since most roads have some crown to them. Typically, cars are actually set up so they're specs aren't the same left and right, they dial in a little pull to the left to counter the effect of road crowning. Racers of all kinds don't like this and set their alignments up the same side to side, but out on the public streets that means they tend to pull a little to the right because of road crown. Or it could just mean your alignment was never right to begin with.