1966 Rad options with electric fan - Impala Tech
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post #1 of 10 (permalink) Old 03-06-2020, 08:52 AM Thread Starter
 
 
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1966 Rad options with electric fan

Any help would be great. looking to put a new rad in with electric fans. BB 496
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post #2 of 10 (permalink) Old 03-06-2020, 10:43 AM
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You can add electric fans to any radiator as they are sold separately. If you are going to go that route which I advise against it. Use new SPAL brand fans as they are the manufacturer that FOMOCO uses as an OME, so they will be reliable in operation. if not in cooling. Electric fans don't move as much air as the stock mechanical fan does (seven blades, eighteen inches in diameter). They are limited by the fan's electric motor.

I prefer an aluminum Griffin twin row if you want it to look stock when painted black.

1966 - 1967 Chevelle Aluminum Radiator

Be-Cool offers a direct fit for double the price of Griffin, but their fabricated tanks won't look stock.

https://www.google.com/shopping/prod...LFAWQQ8wIIoAM#

Then there is Cold Case a new company I have never heard of that offers a Chevelle radiator saying it will fit a full size:

https://www.google.com/shopping/prod...LFAWQQ8wIIoAM#

It will fit in the car but it is smaller than the factory copper brass radiator, and because it is made of aluminum it won't cool as well.

Though looking at the direct replacement radiator from Rook Auto (sized for a 327, not a 427 so it is already missing a row of tubes) it is the same size as the Cold Case above.

https://www.rockauto.com/en/moreinfo...bUg3zCqusUF3GF

You can not have a radiator that is too big (the thermostat will prevent it falling below operating temperature). I size my radiators out of light trucks as that is the largest radiator based upon core size made that I can stuff under a hood (it requires fabricating a different mount). I often call up Griffin for a custom fabricated radiator with three cores instead of two as I build my motors as large in displacement as I can (582-632 cubes) which produces a lot more heat than a stock engine.

Remember your radiator must shed one third of the heat in BTU,s that your engine makes in horsepower.

Convert horsepower to btu per hour | power conversion

Big Dave

Last edited by Big Dave; 03-07-2020 at 09:24 AM. Reason: in need of an edit
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post #3 of 10 (permalink) Old 03-07-2020, 08:34 AM Thread Starter
 
 
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Thanks Dave
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post #4 of 10 (permalink) Old 03-13-2020, 09:49 AM
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A modern aluminum radiator does not actually have to be as thick or have as many rows as the old copper brass ones did to do the job. Aluminum dissipates heat faster, Dave is right about not really being able to go too big with a radiator. But at some point you’re just throwing money at it. Serape also makes good electric fans, as do a few others. You hint have to go buy the most expensive fans just because a manufacturer has that company in their pocket.
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post #5 of 10 (permalink) Old 03-13-2020, 09:52 AM
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Derale is what I meant , not serape not sure why my phone changed it to that at all
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post #6 of 10 (permalink) Old 09-03-2020, 08:03 AM
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Damn autocorrect, am I right? Also been sending wrong messages due to that bugger.
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post #7 of 10 (permalink) Old 09-03-2020, 10:43 AM
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Quote:
Originally Posted by snoopy1 View Post
A modern aluminum radiator does not actually have to be as thick or have as many rows as the old copper brass ones did to do the job. Aluminum dissipates heat faster, Dave is right about not really being able to go too big with a radiator. But at some point you’re just throwing money at it. Serape also makes good electric fans, as do a few others. You hint have to go buy the most expensive fans just because a manufacturer has that company in their pocket.
This is incorrect.

Copper is the best (in terms of conducting heat or electricity). The absolute best metal at conducting heat or electricity is gold; but it costs a lot more and is even weaker than copper is, so you would have to further reduce the pressure caps rating. Gold conducts heat so fast that a pure gold ring doesn't feel cold when you put it on (an old medieval test)

The factory went to aluminum radiators not long after the US Mint gave up on solid copper pennies. And for the same reason: raw copper costs far too much now that the worlds reserves of ore have been depleted. Since WWII the price of copper ore has increased seven fold.

Another advantage of aluminum is you can TIG weld it together (copper radiators are a brazed and soldered together assembly of copper and yellow brass). Welding makes for a stronger joint than a soldered joint. Because of this you can increase the pressure in the cap to raise the boiling point (but not if you still have a soldered together copper water heater core).

People obsess about the coolant temperature but the truth is the only limit on heat in the engine is keeping the oil temp below 240 degrees. Above that it oxidizes and creates ash that wears out the bearings rather than lubricate them. I might add from studying the Otto engine cycle (how a gas engine runs) you can easily see that the colder you make the bottom curved line the more horsepower you can extract from the engine. It is why racers prefer a 160 degree thermostat. The factory uses a 190 to 210 degree thermostat in modern cars to reduce emissions; factory spec for 1966 was 180 degrees.

Big Dave
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post #8 of 10 (permalink) Old 09-03-2020, 03:50 PM
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dave, do you have some reading material in respect to cooling and the items you mentioned in your post (aluminum vs copper, soldered vs welding, high pressure vs low pressure, boiling points, etc)?
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post #9 of 10 (permalink) Old 09-03-2020, 04:21 PM
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There is no one article that covers this. as to strength of materials they are covered in engineering books. There are also books on welding inspection to meet American Welding Society specifications (pressure vessels and pipe certification). But these are all technical and are not for an end user generally. You can Google Brazing, and Soldering but in general
Quote:
Properly brazed joints can be stronger than the pieces being joined, but are not as strong as welded joints. Brazing also has minimal effects on the two metal parts. Soldering is a low-temperature analog to brazing. ... The bond is not as strong as brazed joint or welded one.
Just like with a pressure cooker, the higher the pressure the hotter the temp inside the pot will be to cook food faster. The standard soldered radiator will be rated at only 10 to 12 pounds. But you can buy a 16 to 24 pound pressure cap (often smaller in size to prevent use on a soldered radiator) for your aluminum radiator to raise the operating temp before your coolant boils.

All fans (even electric fans) require a shroud to duct the air through the fan off of the radiator. Radiators cool best with a fan behind the radiator pulling air through at idle while allowing air to flow through when the car is moving down the road.

Most people don't even think about it, but an electric DC motor becomes a generator if it is driven (by wind through a fan for example). As the RPM increases with the cars forward speed it results in a higher than nominal voltage in the fan power circuit, Without diodes and resistors in your fan control circuit, you can fry any sensitive digital equipment installed such as a HEI distributor, or a CD ignition box, or an engine control unit (computer) for EFI, or even your prized stereo boom box and amp.

Engineers trained in the sciences think of these things, but not all back yard mechanics have the level of training than an engineer has, so they don't. They just go on line and complain about what a rotten product "X" is because it died on their first test drive after installing some big electric fans.

Big Dave.
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post #10 of 10 (permalink) Old 09-04-2020, 08:21 AM
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Copper conducts heat better, yes but that is not the entire story. Radiators are made of brass...
Comparisons have to be made using the alloyed material over the range of operating temperatures because conductivity changes with temperature. In several instances, brass does not compete with an aluminum alloy:


I will add in that I don't know which brass and which aluminum alloys are used for radiators.
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1969 Impala convertible build thread here:
https://www.pro-touring.com/threads/...ghlight=impala
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