I have a 74 SCS with a 390 and I am having overheat issues. I went through the engine and put a new water pump and thermostat on it. It has a 4 core stock radiator and I am thinking that it is not cooling properly. When I flushed the coolant it was really ugly rusty. I got it cleaned up and the coolant is nice and green. I deleted the flex fan and shroud and installed a 16" electric fan with thermostatic controller that turns on at 180. I was thinking about having the rad tanked and rodded out but it may just be cheaper to replace it with a better radiator? Maybe? Any suggestions? Seems to be okay on its own but when I tow with it, it doesn't take much at all to overheat it. I figure that with that 4 core radiator that it ought to take a lot to overheat it.

 

Lately your fellow FTE'ers have been raving about Champion radiators.. Ebay.... also sold by National Parts Depot.


Even an electric fan should have a shroud to maximize efficiency.


Go with the monster 19-inch Lincoln Mark VIII fan.. it'll suck a cat flat to the grill.

 

Overheating at idle sitting at stop lights or, cruising down the hiway?

With an older engine that hasn't been apart in a long while if ever you'd definitely want to make sure the block is flushed out as good as practical. There are a couple squarehead bolts on either side of the block to help with this.

 

check out this thread.

https://www.ford-trucks.com/forums/1...l#post15563516

 

Unfortunatly, last I checked, Champion does not make the Super Cooler sized radiator. I found an all aluminum 3 core Super Cooler sized one on ebay for 189 shipped. Aluminum radiators are more thermally efficient than copper/bronze due to the fact the lead solder doesn't transmit heat well at all. The tubes can also be larger and fins more closely packed adding to the efficiency. http://www.ebay.com/itm/271829267277?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

I'm not sure I agree 100% with your argument, but you make some valid points.

What I'm more interested in, as always, is the science behind radiators.

It seems that think article (looks like its old too!) has some interesting information on radiators.

Cap-A-Radiator

Here's a 4-core aluminium radiator. Looks like it's in stock!

 

Not overheating at an idle. Hooked up the fifth wheel and took it for a short tow and it overheated. The truck had not run since 2002 and I tore the engine apart after I had done an extensive flush with Cascade dishwasher soap... which we use to clean big rig cooling systems with great success. It came really clean then I tore the top end off and did the heads, water pump and put a new 180 thermostat in. Seems to have good flow looking at the top tank coolant but I don't trust that to be true. Ordering a new all aluminum 4 core and will mod the shroud to hold the 16" electric fan. That bad boy moves a crap load of air so that can't hurt. I know it is WAY better than what the OE flex fan could do. If that doesn't do 'er, I will go looking for other electric fan options at the wrecking yard. I can't see it overheating with new everything though. Will go back through my carb tuning as well to make sure I am not giving it too much juice, however I have it not lean but it is not rich either. I set it all up and had 20" of vacuum so I know I have it pretty dialed in carb wise... though I left the off the shelf power valve in there (and I don't know what effect that would have with overheating).

 

Aluminum heats up less as it absorbs heat allowing it to continue absorbing heat it seems the temperature gradient created would keep the outside cooler making it not lose heat to the air but it's just a guess unless someone want to stick a thermometer to their radiator until then I would stick with the common knowledge that aluminum is better

 

20" might be a little too far advanced and can be a source or cause for over heating. Dial down to 18", up the curb idle and check air/fuel with the vacuum gauge again.
Agreed with the radiator suggs above.

 

Actually, that's not entirely true. The aluminium radiator is better for cooling yes, but it depends also on your application.

The only reason aluminium is better than an old school copper radiator is because of the soldered joints required to attach the fins to the rows/core.

Lead solder has a thermal conductivity of 35 W/(m*K).
Copper has a thermal conductivity of 401 W/(m*K).

Aluminium has a thermal conductivity of 205 W/(m*K).

Thermal Conductivity of some common Materials and Gases

Technically speaking, copper has a much larger capacity to transfer heat than aluminium does... but due to the manufacturing of copper joints (lead solder), the heat transfer of the copper is HIGHLY restricted (by the lead solder) between the copper core and the copper fins....

Meanwhile, the aluminium radiator is 100% aluminium.... so it's thermal conductivity is consistent at 205 alllllllllll day long.

 

[QUOTE=Aaron-71;15565355]

The only reason aluminium is better than an old school copper radiator is because of the soldered joints required to attach the fins to the rows/core.

QUOTE]


Not completely true. Since the tensile strength of aluminum is higher than copper and brass, the tubes can be larger giving a larger surface area for heat transfer, and the fins can be packed closer together.

So, an aluminum radiator with the same physical dimensions as a copper brass will have a much larger cooling area.

And yes in theory a copper/brass should be a more efficent design because properties of heat transfer. Lead is the problem.

There is a reason that OEM applications almost all use aluminum for radiators, condensors, heater cores, evaporators, and charge air coolers(intercoolers). The few later model coppers I have seen have only been in Hondas, but even those were from the '90s.
Edit: added links.
http://www.hotrod.com/news/hot-rodradiator-selection/
http://www.hotrod.com/how-to/engine/...-for-your-car/

 

[QUOTE=54Hydro;15566672]This is very wrong actually. Copper has 4x the ultimate tensile strength that aluminium does.

Copper (210 MPa):
https://www.google.ca/webhp?sourceid...ngth+of+copper

Aluminium (50 MPa):
https://www.google.ca/webhp?sourceid...h+of+aluminium

Yes, this is true, but it's not due to its ultimate tensile strength. It's due to its ductility and malleability.

The reason aluminium can have more fins/inch is because aluminium has much higher manufacturing tolerances due to its very high ductility, making it very malleable. Copper is a ductile material when compared to say, cast iron, but in comparison to aluminium, there's not even a debate to be had.

 

But now you have agreed with both my points in my first post on this tread:
1. Aluminum radiators are more thermally efficient than copper/bronze due to the fact the lead solder doesn't transmit heat well at all.
2. The tubes can also be larger and fins more closely packed adding to the efficiency.
So in effect, you do 100% agree with those two statements, even if you didn't mean to.

 

Wait until...
Where are you located? I have a used HD radiator from an F-250 that I'm parting which cools really well. If you're far from California, it's probably not worth considering...

 

Shipping via Greyhound might be pretty cheap, or find an FTE member runnin' from the law headed that way to drop it off.