At 04:40 PM 11/19/99 -0800, Max Heim wrote:
>What does an A have for a carb heat shield?
It has a piece of sheet metal between the carbs and the exhaust manifold.
At the ends of this piece there are two bits of asbestos on the side
towards the exhaust manifold runners for ports #1 and #4, roughly opposite
the float chambers on the carbs, presumable to protect the float chambers
from direct radiant energy from the exhaust manifold.
Unfortunately there is no asbestose in the middle of the sheet adjacent to
the combined exhaust runner for the #2 and #3 port (singular). With twice
the exhaust gas going though this center runner it must be getting even
hoter than the #1 and #4 runners, and there must be considerable radiant
heat energy getting through here. This would be heating the center of the
aluminum intake manifold as the part in closest proximity, and also the
carburetors to some extent. I suspect it might help some if there was
another piece of asbestos installed in the center of the heat shield.
>I wonder if you could back the thin metal shield with some of that
foil-faced underhood insulation or header wrap material, to try to keep the
exhaust heat off the carbs?
I suppose the B doesn't have any padding on the heat shield? It might be
worth an try.
>Or, I suppose you could route a cold air duct from under the bumper
somewhere .... that would blow on the outside of the carbs. ....
The MGC (at least some of them) had a blower with an air duct directed at
the carbs for just that reason. I believe it was on a thermostat that
would turn on the blower under high heat conditions. That may be good for
the C, but on the A there's not much room for the blower, even though there
is already a duct there in front of the carbs.
Barney Gaylord
1958 MGA with an attitude
http://www.ntsource.com/~barneymg
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