Suspension geometry question

[RICKDIZZLE]

Ok so I am turning to you guys as I need some help figuring this out for my buddies 1963 Impala. The car is on air bags and at driving height the car is sitting at negative 2.5° of camber. There are no shims in the a-arm at all right now...so no way to pull shims out to get it even. The car had hydraulics years back so we are sure the the front end of the frame is sagging..thus giving us the negative camber. We can get and install upper a-arms extended 1, 1.5 or 2 inches. This would obviously push the ball joint out adding positive camber and we could shim back as needed. Is there a formula or way to determine about what extension we should go to get it close?
He is not intrested in adjustable tubular a arms as his car is full show and he would like to keep to a extended and molded chrome upper to match the rest of the suspension. Any help on the math would be killer!

 

[oldsmobile joe]

I thought 63 chevy full size cars had a cam bolt on the bottom control arm to set camber. I might be wrong

 

[RICKDIZZLE]

Pretty sure that was the Chevrolet Nova II. The Impala doesn't have that unfortunately..at least 1963.

 

[pagrunt]

Have you looked into to see if the frame is still in or close to spec?

 

[RICKDIZZLE]

Have you looked into to see if the frame is still in or close to spec?

We know its probably not due to it previously having hydraulics and being hopped on and 3 wheeled on. However...the frame is fully custom painted and the car is fully back together. So the owner isnt looking to get frame work done...fully hear what your getting at Pagrunt. So I just want to get him close with running extended uppers and then shimming as needed to get that negative 2.5 camber out at ride height. He is kicking himself for not checking the frame before everything got painted and back together. Hope that makes sense.

 

[pagrunt]

We know its probably not due to it previously having hydraulics and being hopped on and 3 wheeled on. However...the frame is fully custom painted and the car is fully back together. So the owner isnt looking to get frame work done...fully hear what your getting at Pagrunt. So I just want to get him close with running extended uppers and then shimming as needed to get that negative 2.5 camber out at ride height. He is kicking himself for not checking the frame before everything got painted and back together. Hope that makes sense.

It does.

 

[RICKDIZZLE]

This was it before he married the body back to the frame couple years ago..He touched EVERY nut and bolt on that beast!

Just trying to figure out if there is a calculation we can do to determine if he should go 1, 1.5, or 2 inches on the uppers to allow the tech to shim it and set to ride height.

 

[Supercharged111]

I'll wager a WAG and say you'll be closer to an inch than 2. It'll be the arcsin of the distance that needs to be added to the upper arm divided by the distance between the upper and lower balljoints to get you to 0.

 

[RICKDIZZLE]

I'll wager a WAG and say you'll be closer to an inch than 2. It'll be the arcsin of the distance that needs to be added to the upper arm divided by the distance between the upper and lower balljoints to get you to 0.

My thought is about the same..thinking about having him go with the 1.5" thus allowing some wiggle/adjustment room. I found this info on the interwebs. Of course this is all relative to the tire and vehicle...but figured gets us close.

 

[xcookpac]

My thought is about the same..thinking about having him go with the 1.5" thus allowing some wiggle/adjustment room. I found this info on the interwebs. Of course this is all relative to the tire and vehicle...but figured gets us close.
View attachment 216597

I like your concept but I find your formula* which includes computing tire diameter causes the process to be less than straightforward. IOW, I physically measure my tire diameter while tire is properly inflated with car level, and on level ground. My current tire is 26" in diameter. If I am trying to get one degree of negative camber then I multiply 26" by 0.01745 (sin of one degree) which equals 0.45 inches**. Then I use a builders square on a level floor to measure difference from vertical (the builders square represents vertical) at the top and bottom of tire sidewall. With negative camber, the top of the tire should be 0.45" closer to the centerline than the bottom of the tire.

*- Tire Diameter ("TD")= Tire Width (mm) * Aspect Ratio/100 *2/25.4 + Wheel Dia.

**- 26inches x sin(1 degree)=26" x 0.01745=0.45"