Washer thickness calculation for increased camber

[moonshine_mike]

Just Completed a wheel alignment on my 70 Cuda. I wanted to share my calculations and math behind the the setup.
Desired target was Camber -1.5deg, Caster +2.5deg.
No way to reach this with stock architecture.
Step one:
Add Moog K7103 Offset bushings which increased the caster to about +2.5 when the adjustments were set to maximum. This left no way to adjust the Camber which was 0.0deg. I needed to add washers to the lower ball joint which I have never done before. How much washer? Using a little bit of trig and some assumptions.... See the pictures also.
1) Vertical distance between top ball joint pivot and lower ball joint nut is about 7" Therefore VERTICAL is = 7
2) Desired to add 1.5deg  more to the Camber Therefore ANGLE INCREASE is 1.5 (I mirrored the equation so angle is pos)
Equation: WASHER THICKNESS = Tangent (ANGLE INCREASE) X VERTICAL
          WASHER THICKNESS = Tangent (1.5) X 7
          WASHER THICKNESS = .183"

I ran to ACE to get the grade 8 hardware and installed a washer  with thickness equal to .181 and new bolt since stock was to short.
Re checked alignment resulting in no change to Caster, but got a -1.5 deg Camber on passenger side as planned. The math seems to work.

Turns out for every degree more negative Camber I want, I need to add about .122" thick washer. This will help for my future alignments.

[Brads70]

Just for future reference for someone down the road, what size and length of bolt did you use? 

[moonshine_mike]

New bolt was 5/8-18 X 3"
Hardest part of the entire project was drilling the cotter pin holes. Had to construct jig, had no drill press, had no cobalt drill bits, blazing 110 degree sun outdoors. Broke a titanium bit and dulled two others but finally got it accomplished using a custom jig, vise, and hand drill.
I would do it again if needed for my other E bodies. Next time I'll buy a suitable drill bit.

[MoparLeo]

Obviously your alignment specs are not for normal driving.
Should mention the reason for the negative camber.
 Normally hard turns.. Not for tire wear.

[moonshine_mike]

Fair point. The increased CAMBER will likely wear inside edge of tires faster than a lower CAMBER.
I was mostly just trying to show a mathematical relationship between degree of CAMBER vs WASHER THICKNESS and then using an example experiment to illustrate. 
The actual settings target I was using for this car comes from the SKOSH CHART guidelines set to MAX PERFORNACE STREET with a CASTER of 2.5 to 3.5 and CAMBER of -.75 to -1.0.  (I tweaked CAMBER on passenger side to -1.5 in my example, added some for road crowning, Driver side set to -1.25deg)
I will test it out over the next few weeks, compare to another E body, and adjust as needed. May go back down, which I now feel easy to do.

   

[7E-Bodies]

M @moonshine_mike  So if Oscar had a hairy old arse, could he still align a front end? 
(Guessing only the trig guys will get it). Anyway, impressive to see someone using trig. I'm a few years retired (early retirement), but used it in my job bending the numbers on power line protection schemes to determine fault distances, phase angles, and magnitudes on substation relay equipment. Your post will come in handy for anyone fighting alignment issues in the future. Nice work.

[MoparLeo]

Usually caster is adjusted to compensate for a lot of road crown. Not much crown on modern roads as the drainage is much better than old roads.
Hi-way and freeway crown is almost non existent.
And adjusting caster to compensate for road crown will allow the car to drift to the left which is not ideal for safety.