[DeTomaso] radiator

[JDeRyke at aol.com]

In a message dated 7/25/07 4:30:45 PM, garth_rodericks at yahoo.com writes:

<< To be honest, I imagine the thermal efficiency differences are so 
negligible considering the increased size of most aluminum radiators that it probably 
doesn't warrant our attention..... thermal efficiency is the least of my 
concerns in the brass vs aluminum radiator debate for reasons cited above. I'm more 
concerned with reliability and serviceability. >>

Correct- theory doesn't always mean anything. FWIW- radiator shops fix 
core-leakers in one of two ways: either they flush the rad with some sort of 
stop-leak compound, or they pinch the leaking tube(s) closed with pliers. You thus 
lose function in that tube or tubes, but such a small change is not normally 
noticable in a street car. No shop desolders a tube to replace it- thats 
impossible at today's wages per hour. And no shop tries to resolder a tube thats 
broken loose at either end. Either the leaky tube is squeezed shut or the core is 
replaced. Thie stop-leak or the pinch method works for aluminum as well as 
copper, by the way. 
Leaking tanks CAN be repaired but this is kind of a rare failure except in 
GM's plastic tank rads; those abortions are failure-prone in any car and cannot 
even be replaced unless the shop has the giant machine that crimps a new 
plastic tank onto an existing core. 
Finally, racers use aluminum rads simply because they're less half the weight 
of a copper rad, and they keep an engine cool. Varying the tube count in a 
core will radically change the function of any radiator, and more tubes does not 
automatically mean better cooling- it depends on a host of other things 
including air speed thru the core, the horsepower of the engine & its efficiency. 
Core tube counts past a certain number will restrict airflow and the engine can 
actually run hotter with a bigger core. Hall used to sell a 7-tube core for 
Panteras but most people found that this 65-lb monster didn't work as well as 
one half its size and 1/4 the weight. Gary no longer sells it and will be the 
first to tell you it just didn't work. He also tried one in which the whole 
core was slanted so airflow thru the grille had a straight shot thru the core; 
that didn't work worth the fabrication expense, either. Air removes more heat if 
its tubulent so there's more air-to-fin contact. A smooth air flow didn't 
pick up all the heat possible. But at least Hall was innovative and not afraid to 
try things on running engines. FWIW- J DeRyke
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