Hi,
As I was going over my 100-4 BN2 frame one more time before sending it off to
paint, I noticed the left front suspension front A-arm bracket sitting higher
than the right one. Measurements confirmed that it is about 5/16" higher, the
rear A-arm bracket is about 3/16" higher than the left one.
This prompted me to re-attach the front suspension and re-evalute
camber/caster. I took multiple measurements with a digital level with a
magnetic mount that snaps to the hubs and I confirmed camber with a plumb line,
measurements and trig math (to be honest using a calculator on the web.)
Here's the results:
LH Camber 1.1 shop manual spec = 1.0
RH Camber 0.6
LH Caster 1.2 shop manual spec = 1.75
RH caster 1.7 (caster measured from -20 to +20 degree wheel rotation)
I could adjust the camber with the upper adjustable offset bushes and actually
bring this close to 0 degrees which seems to be the current preference with
modern tires.
Note that the car is on a rotisserie, connected by the bumper bracket mounts.
It is easy to level the car. The car is not loaded, no engine/trans just the
frame + body panels so no flexing.
The caster numbers confirm the measurement of the brackets height.
1/8" of height difference between front and back compared to left correspond
roughly to 0.5 degrees. So adjusting the caster will require cutting and
welding brackets and probably shock plate.
But before I do that I would like to ask if a 0.5 degree difference in caster
is noticeable. These numbers could also change again when the frame is fully
loaded. They probably will as the left rail was repaired with kilmartin
sections, so this one is probably a bit less prone to flexing. I remember
camber was measured at the reputable Healey shop where we did the body/frame
repair and was exactly 1 degree on both sides with the car pre-loaded with
700lbs of lead simulting engine/trans weight. I am unsure however if/how
caster was checked.
Upon removal I tagged the suspension according to the side of the car but the
previous owner could have things swapped around. So I might also test changing
the suspension from left to right and re-measure. Is this usefull at all?
Am I fretting to much over this? Is 0.5 degrees difference still within spec?
Should I just have the frame painted, the car assembled and see how the car
rides and bring it to an alignment shop and change things if required?
Sorry for the long winding email,
Looking forward for your advice and experiences
Bert
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