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Definitive results of tests on factors influencing cooling

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blueskies said:
Somewhere in this thread, someone mentioned adding an aluminum radiator to a Healey. Possibly other design elements of the Healey defeat the possible advantage of an aluminum radiator, but in other vintage cars, an aluminum radiator can make a huge difference. In a big block Chevelle, for example, an aluminum rad provides a simple, although pricey, solution to overheating.
Click to expand...

I think aluminum would be a good upgrade to the stock radiator. It would almost provide superior cooling provided you have good airflow, but it's the airflow that seems to be major problem for me. I re-cored my radiator and my car essentially never overheats as long as I'm moving -- even pulling steep mountain passes in summer heat. Once I stop, it's a different story. I doubt aluminum would really help then.
 
The relative thermal conductivity values of various radiator metals are roughly as follows:

Copper 400
Aluminium 200
Brass 100
Steel 50

These numbers have been rounded slightly but give an accurate heat transfer value relative to each other.
 
Since copper itself is a good conductor of heat, quite possibly the superior cooling of some aluminum radiators has to do with other design elements. Bigger cores, more efficient design, etc. may make a big difference. A company by the name of Alumitech specialized in making exact fit reproduction radiators for Chevelles. With black paint added, they looked correct in size and shape. The one in my 396 SS cured all the overheating issues - both at speed on the highway and at idle. We don't get Arizona or Texas type heat here, but we commonly have '80s and '90s during the summer. Not sure what is available in aluminum radiators for Healey's.

Another car, with a 283, has a double electric booster fan installed on the inside face of the stock radiator. The car still has the original mechanical fan, but the electric fan does help in a low speed idle situation. The booster fans are hidden away in the radiator shroud and not visible. A manual switch under the dash turns themn on and off when needed.
 
Aluminum radiators don't provide better cooling because of aluminum's thermal conductivity (it's not at good as copper's), they can be designed to cool better because aluminum is mechanically stronger than copper.

This allows them to design aluminum radiators with different geometry. They can be built with higher surface to volume ratio and still maintain structural integrity.


pc
 
Are our (stock) radiators made with copper or brass (I'm pretty sure the top and bottom tanks are brass, dunno about the tubes and vanes)?
 
Bob_Spidell said:
Are our (stock) radiators made with copper or brass (I'm pretty sure the top and bottom tanks are brass, dunno about the tubes and vanes)?
Click to expand...
copper tubes.

The reason aluminum radiators are an improvement is that the cores have more tubes and the fins are a modern design. I recored my original radiator in copper and it works just fine. Unlike some places, we get over 100F days. I overheat before the Healey does!
 
Installing an aluminum radiator would also be an improvement over an old crudded-up stacked-fin stock radiator. I recored with a 4-row folded-fin design which may work as well or better than an aluminum radiator of the exact-same size. However, it will be weaker and heavier.

The article I linked to above explains the soldering of the tubes to the tanks in copper/brass rads inhibits the heat transfer and that the aluminum ones use a type of welding which allows better heat transfer.
 
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