UCA/camber question

[gmjj13]

ok, here's the dilema...

i know everyone is going to say loose the spindles...but i'm having no issues with the tie rods or anything else for that matter.
here's my current setup. heidts 2" drop tall spindle, hotchkis 2" drop BBC springs, stock upper and lower control arms with del-a-lum bushings. after the spindle install, the camber is way out.

my question is can i run a 1" narrowed UCA and the stock lowers and not have any issues? it would seem that the narrowed upper would bring everything back in spec.
i don't like the idea of having an inch or more of shims between the frame and control arm, not to mention moving the UCA closer to the headers. i did a search, but couldn't really find an answer to my specific setup.

here's a pick with about 1/2" of shims to try and bring it back in.

[gmjj13]

anybody?

[Tyler Beauregard]

Looks like you have positve camber gain. What uppers are you running right now, and what did you try and align it to?

Most guys won't reccomend a shorter upper control arm, you aren't exactly fixing the real issues, just masking it.

Tyler

[Norm Peterson]

The OP did say 'stock' control arms.

Anyway, the ability to get to a specific camber setting with a tall knuckle depends a lot on what the OE inclination of the uppers was with the OE knuckle. If they ran 'uphill' from balljoint to chassis-side pivot, then a taller knuckle will cause the UBJ attachment point on the UCA to initially move outward as it moves upward to accommodate the now-higher upper balljoint location. It may or may not reverse this outward lateral direction of movement at some further amount of upward travel. Even if it does, the camber gain may still not go back to negative with suspension bump travel, depending on what the lower arm and its ball joint is doing (laterally).

It also depends on the spindle geometry - what the included angle is as well as the height between ball joint centers. If the spindles/knuckles were built for this chassis, this should at least be in the ballpark. Were any specific notes regarding alignment supplied with them?

Shorter UCAs can solve the camber problem, but can be expected to introduce bumpsteer errors. No freebies here. Fixed-length uppers are available from the circle track supply houses in (IIRC) 1/2" length increments. But again, be careful because the roundy-round guys frequently use a left side UCA that is not the same length as the right (and I never seem to remember which side you want two of). Or for a little more $ (and available from Marcus at www.scandc.com) an adjustable length upper may work.

I'm not real crazy about the idea of cutting and rewelding the stockers, and would hesitate a LONG time about doing that as a DIY task. Too many ways to screw something up. At a minimum, I'd talk to a certified welder with automotive chassis experience regarding the fabrication issues (and keep in mind that the above-mentioned bumpsteer issues would be present) and plan on adding some reinforcement.

Alternatively, just replacing a fat stack of shims with a larger size thick block plus one or two thin shims for fine adjustment would make for a more stable condition. This doesn't solve the header clearance issue or the bumpsteer, though.


FWIW, I ran with at least half an inch of shims on the thumbnail car all the time, and with something like 3/16 to 1/4 inch more for autocross just to get reasonable negative camber numbers for those activities (considering my own driving) instead of the zero-to-plus numbers specified by Chevrolet for its lowest common denominator customer. Yes, I did end up with a couple of dented header tubes (but no cracks or leaks). Everything moves around a little when you're running it hard.


Norm

[darren@ridetech]

The Moog shafts are offset. One side of the shaft is labled "Wheel Side". If you install it as instructed it will push the top of the spindle out and you will have to run a lot of shims to get camber set. I haven't tried it yet but I think that you should be able to flip the cross shaft over and run less shims with the same amount of camber. That may be too much on some cars tho.
Has anyone ever tried this?

[ProdigyCustoms]

I answered over at Camaros. Darren is dead on about the offset shafts. Unless those Heidts spindles "require" their shorter arms. If so, your screwed.

[gmjj13]

thanks for the info. it seems like the SC&C arms would be a improvement over stock. i'll check my shafts and see if that will help first, thats one thing i didn't know about. i appreciate all the responses. thats what i like about this site/community.

FWIW, if i could afford to do it, i'd be giving Darren a call today and ordering everything i need. unfortunately, i'll have to wait a while before i can afford it. thanks again for the responses...

[gmjj13]

just placed my order with Marcus at SC&C.
ordered the pro-lite upper arms and the FASTRAX gauge. awesome to deal with, answered all my questions on suspension/alignment, and then some i can't wait to get my new arms and get everything put together and aligned.