Subject: Time:4:16 PM
OFFICE MEMO Block paint & SU downdrafts Date:11/12/93
Sergio Montes wrote: Lastly it is intriguing to speculate what caused the
demise of the vertical
(downdraft) SU carb found in quite a few British cars of the late thirties,
including the Wolseley mentioned above, the Lagonda V-12 and
others.The standard argument, that the piston wore excessively on the lower
side seems not very convincing.
My tuppence: I'm looking at a cross-section picture of a downdraft SU for a
1936 1-1/2 liter SS Jaguar (they bought this engine from Standard in those
days). For those who have never seen one, its your basic SU turned on end,
vertical throat, horizontal piston, but the float bowl is still vertical so the
connection to the carb body is a 90 deg. arrangement. There is an oil cap but
no damper in the piston shaft. 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, and to put a few drops of light sewing machine oil on the rod.
Maybe they found they needed the damper but it wouldn't hold oil in the
horizontal position.
On paint inside the block: Every cast iron block and cast iron trans case I've
ever seen was painted on the inside.
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