From:
doctorduke_REMOVE_666949_THIS_@yahoo.com
--- In <a href="/group/cosworthvegas/post?protectID=219233066105193209050199029077192253163098100009128121188190230091025019053061151110147">cosworthvegas@yahoogroups.com</a>, longg01 <<a href="/group/cosworthvegas/post?protectID=091233212180056219138097203245129208071">no_reply@y...</a>> wrote:
> Does anyone have any suggestions for alignment specs? I was
> thinking -1 degree of camber, 0 degree of caster, and 1/16 toe in.
>
> Thank you everyone who gave me help in the past with suspension or
> brake questions. I now have my car running, turning, and braking.
> ~CHRIS
> #0754'
Sounds like you must be reading your TCT Portfolio. These are the
specs I recommend for best street performance.
The geometry of the lower control arm results in a loss of caster as
you increase camber in the negative direction. My suggestion is to
set the rear cam bolts, which control caster, to the full positive
position, which pushes the pivot point as far outboard as possible,
then set the camber at -1 degree and go back and tweak the caster cams
until you have achieved as much in the positive direction as possible,
EQUAL ON BOTH SIDES. Since the front cam bolts have a slight effect
on caster and the rear cam bolts have a slight impact on camber this
is somewhat of an iterative process, but the above approach should get
you to the best position in a minimum number of iterations.
You want some positive caster, if possible, but with -1 degree caster
you will be doing okay if you can get both sides to zero caster.
I am currently running -2 degrees camber and the most caster I could
get at the limit of adjustement, equal on both sides was -0.75
degrees. With 1/16" toe-in the steering had very poor on center feel,
so I changed the toe setting to 1/16" out and it's a little better,
but still not as firm as I would like. I'm looking into moving the
ball joints rearward on the upper arm to try to get more positive
caster. More caster in the positive direction will increase on-center
feel.
It's interesting that Chevrolet's toe recommendation changed from
toe-in to slight toe-out as a running change in '76. You can see this
in the change record of the AIM sheet. I've never figured out why
they changed the toe spec so many times, but it might have had
something to do with the adoption of radial tires. Radials prefer
smaller toe settings than bias or bias belted tires. I believe that
in 1975 the Cosworth was the only model offered with radial tires, but
more radial options were offered in '76. I'm suprised that they
didn't have different toe specs for bias and radial tires, but
apparently they compromised on one toe spec, regardless of the type of
installed tire.
I do all my own alignment using an inclinometer and carpenter's tape.
It's time consuming, but I end up with what I want, and I don't have
to deal with the dimbulbs at alignment shops who have little, if any,
understanding of suspension geometry.
Duke
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