>Also, what is the function of the oil in the dashpot in the top of the
>Carbs? A dashpot dampens something, but what?
Jack:
The oil in the carbs dampens the movement of the piston, or slide as it is
sometimes called. The piston rises and falls as a result of vaccuum
created above the piston in the dashpot. When the throttle butterflies
open, manifold vaccuum is increased, and this vaccuum lifts the piston.
Fixed in the bottom of the piston is a metering needle, which hangs
concentrically into an opening through which fuel flows. Since the needle
is tapered, the more the piston lifts, the more fuel is allowed to flow
around the needle, thus maintaining the proper amount of fuel to accompany
the higher volume of air that is now rushing through the carburettor. The
movement of the piston must be controlled so that it does not rise or fall
too abruptly, so they've built in a little shock absorber, of sorts, into
the carburettor. Different weights of oil here control this action to
different degrees. Most folks I've talked to use ATF here. That's what I
use.
Pete Chadwell
1973 TR6
1970 TR6
1973 240z
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