I am responding to the cooling thread, but am blind-copying the racing and
Twincam groups as this may have some interest for them.
50% of the problem with cooling in an MG (I direct my comments specifically
to the MGA, but they apply equally to the lesser breeds ;-), is invariably
cooling system condition.
Clean the darn thing out - get the rad tanked and if necessary recored (some
of the modern optimal cores are a definite improvement over the original, and
check the water pump to see how much vane is left, and whether you have the
right one for your block in the first place. All that should help
considerably.
If you live in the infernal regions (anything South of the latitude of
Seattle), have your radiator modified when you have it in for service, so
that it takes a modern high pressure cap (the older models with deep throats <
no snickering in the back, there!>, will only take a 7 pound cap. With the
new neck you can fit a 14 pound cap.
As long as the coolant isn't boiling, it is just fine. The first time I took
my MGA coupe to a meet in Tahoe and had to crawl through rush hour in Reno, I
discovered the limits of the stock system, but it didn't quite boil. The
local guys told me they were never UNDER 200 deg. As long as it isn't
boiling, it isn't hurting anything (though you better make sure your hoses
are in good shape).
The other 50% of the problem is that much of the air that hits the front of
the car goes around rather than through the rad core. Some ducting work can
significantly improve matters - foam around the sides, renewing the rubber
excluder at the top of some models, or the felt strip almost always missing
from the MGA bonnet helps.
Last, for the racers (these mods require departures from stock appearance -
on my Twincam race car, I had a good look at things and decided what to do,
and it WORKS. I looked at the thickness of the rad tank and concluded that
there was no reason that the core had to be half thickness (the top tank is
wider than the bottom). Either use two top tanks or make up a custom bottom
tank, and you get twice as thick a core. Move the rad into the nose a bit
and use foam to duct all the air you can through it.
With the rest of the system in good shape, the result of those mods is that
my car runs too cold! I don't use a thermostat bypass, although I do have a
restriction in the piping, but at Seattle I have to tape half the rad over on
a cool day to get it above 160 deg., and on a blistering hot day, it runs at
around 180-190 all day, using 7000 rpm.
Oh yeah - on an A remove the centre grill bars, or half of them, or if rules
don't allow, bend them a bit to improve flow. Damned things are calculated to
let as little air through as they could. Probably designed by the same guys
that did the MGA/MGB head to allow as little flow as possible ;-)
Bill
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