hemi4t wrote:I've got a 392 in my 40 ford and it is newly rebuilt top to bottom running 10:1 compression, 292 duration cam, BBC water pump, and a griffen aluminum rad with a 16 inch 2700 cfm electric fan, and a 160 degree thermostat. The temp seems to hit 180 degrees within minutes and then hover between 190 and 210+ based on stop and go traffic with temps in the 70 and 80's. The timing is at 6 degrees before and total of 30 degrees by 2500 rpm. The fan is set to come on at 185 degrees. Is 210+ too hot for these engines?
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210 is technically *not too hot*, but if that's were your running normally, it's
a bit scary, because there's not much of safety margin. Under a load it will
probably quickly go hotter and get into the danger zone. Ideally you should
be running at about 180 to 195 degrees under all conditions. Below 180
degrees, you'll lose a bit of power and hurt fuel mileage too. Much above 200
degrees and besides not having have much of a safety margin. you increase
the octane requirements of the fuel and can run into pre-ignition or
detonation problems, forcing you to back off on the timing and thus lose
some power and mileage. The fact that you have a 160 degree thermostat
and you're still running at 210 degrees indicates either the rad is not big
enough and/or you're not getting enough air flowing through it. A few things
to check before you go changing the rad. For incoming air to flow in
through the rad properly, it has to also be able to escape the engine
compartment too. I imagine an early hemi in a '40 Ford engine compartment
is a pretty tight fit. Can the air escape adequately? You might need to
add some additional vents to the hood, or through the inner fender panels
into the wheel openings, to let the hot air out. Also, are you running a
hood scoop of some sort, particularly, one that is not sealed to the carburetor?
Sometimes a hood scoop that's not sealed to the carb can pressurize the
engine compartment enough that it restricts air flowing in through the rad.
Hope some of this helps.
mart
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