Copper brass is a better heat conductor than aluminum, but the amount of
lead solder in the copper/brass radiator construction lessons the advantage.
Aluminum is a stronger materiel than copper/brass, and the tubes can be much
larger. Larger tubes equal more surface area than additional tubes of
smaller diameter. Standard aluminum radiators have 1" tubes. Mine has 1 1/4"
tubes. Copper/brass radiators have 1/8" tubes. Additional rows of tubes
bring diminished returns, so a 4 row copper/brass radiator looses much of
its efficiency on the third row, and almost all of the advantage is lost at
the 4th row. The most efficient radiator seems to be a 2 row aluminum
radiator with 1 or 1 1/4" tubes in a cross flow design, unless, like Barry,
you have unlimited funds, then you would have a radiator made of silver.
Silver has a very high heat transfer rate & is strong enough to be made into
large tubes.
(Electric) fans are more efficient as pullers than as pushers, with some
manufacturers claiming a 20% advantage for the same motor & blade design as
a puller.
Ducting the intake grill to the radiator and ducting the radiator to the
fan(s) will increase cooling to a noticeable degree. Roof flashing is cheap
& easy to work with & can be used with duct tape to make a simple, if less
than elegant, duct to seal the front grill area to the radiator. Fan ducting
is a bit more complicated because of the radical transition of shape in a
very short distance, but you may be able to find a shroud in the salvage
yard that can be modified to fit.
Spoilers combined with ducting can lower running temps. Both the "ST" and
"LE" spoilers work well, with the "LE" spoiler having an advantage.
Jim Stuart
Reply to <jimbb88@comcast.net>
-----Original Message-----
From: owner-mgb-v8@autox.team.net [mailto:owner-mgb-v8@autox.team.net]On
Behalf Of James Nazarian
Sent: Wednesday, September 21, 2005 6:36 PM
To: 'Barrie Robinson'; mgb-v8@autox.team.net
Subject: RE: Aluminum radiators
FWIW I use an aluminum rad with electric fans only. The fans are sealed to
the rad in a puller configuration. They come on every now and then in
traffic run for a bit then go off. I don't use an engine driven fan at all.
It frees up horsepower, lessens noise, etc.
James Nazarian
71 MGBGT V8
71 MGB Tourer
87 BMW 325es
-----Original Message-----
From: owner-mgb-v8@autox.team.net [mailto:owner-mgb-v8@autox.team.net] On
Behalf Of Barrie Robinson
Sent: Tuesday, September 20, 2005 3:57 PM
To: mgb-v8@autox.team.net; mgs@autox.team.net
Subject: Aluminium radiators
While reeling in ecstasy because my MGB GT V8 just flew down to the BIG car
show I still have this nagging ":the engine bay could be cooler when going
slow" thought. While at the show I spoke to Keith Childs he of mechanical
fan (electric back-up which he says never comes on) and aluminium radiator
fame. He reckons that the ally rad is the reason for his machine running
so cool. So can anyone tell me just exactly how much better an
aluminum rad is. I see that the coefficient of thermal conductivity for
aluminium is half that of brass. My rad is the D&D one which I believe is
brass. Are the pipes bigger, thinner, more or what?
Regards
Barrie Robinson
barrie@look.ca
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