Well, I experimented a little with the oils. This unfortunately was a
bench top test, as my car is not running yet.
I can not tell how fast the SU piston rises when the accelerator
is presses, but when I use my thumb and 10w40 oil, I can
only get it to rise to the max in about 4 seconds even with
pretty strong pressure.
5w30 takes half that long, as the viscosity index might suggest.
ATF oil is about comparable to 5w30 or slightly thinner.
One interesting thing I found is that when I tested the other
carb with the same oil, it SEEMED like it always rose slightly slower
with the same pressure (as far as I can tell with my thumb).
I have to check this out further.
I am trying to tell if my thumb is a good benchmark. I figure I can
develop 40 lb easily and maybe up around 60 lb (prob no more
than that due to awkward positioning).
With engine vacuum pulling the piston (area around 7 sq.in.) pulling
at what less than 15 psi (not a perfect vacuum), maybe 10psi, then the
total pull on the piston should be around 70 lb. (someone please
check my math).
Therefore, I think my thumb is a fairly good benchmark. How fast do
we want the piston to rise when you floor the accelerator? I'd say a
couple
of seconds, no more. Maybe 10w40 oil is too thick??? Maybe 5wt is
better????
-Tony
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