Roger Garnett writes (WRT downdraught SUs)
> The oil damper and return spring were introduced in the late 30's or 40's.
>> The instructions in the manual say the piston
>> rod in the bearing is the only part in contact, the suction piston is a
>> clearance fit
>This is the case for all SU carbs, and similar designs. (Well, mayby not
>the ones from the 1900's, with leather diaphrams. I haven't taken one of
>them apart.)
Nope. The SUs of the late 40's early 50's had heavy brass pistons
to provide inertia damping. Sometime around the time of the BMC merger
the pistons were changed to aluminum w/ viscous oil damping as a cost
cutting measure.
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Martin Frankford Teledyne Brown Engineering, Inc.
mfrankfo@nebula.tbe.com (205)726-2366 voice (205)726-3976 fax
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