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Old 05-04-2010, 09:28 PM
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Fan distance for proper cooling

I have installed a 350 in my 83 C-10 Summit radiator, with long water pump, I have a 2" spacer on the flex fan but still I am about 5.5" from the front of the fan to the radiator. I am afraid this won't cool in the heat of the summer... Should I try to move the radiator closer or just add a shroud , maybe switch to electric. How do they get the fans closer on the stock set up?

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Old 05-04-2010, 10:09 PM
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shroud would be best i think, but electric frees up power
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Old 05-04-2010, 10:52 PM
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You will need a shroud, and the fan should be as close to it as possible. Without one, you'll not pull air through the radiator.

I know my SPAL fans came with a built in shroud arrangement, and force all the drawn air through the radiator.
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Old 05-04-2010, 11:25 PM
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Factory added a shroud, fan should be set so 1/2 the blade width is in the shroud and 1/2 is back behind the shroud lip. This is how the factory does it, with the fan in the correct position at the shroud lip the air can escape off the blade tips pulling more air through the core, if the fan is too far into the shroud it chokes off this tip flow.

Without a shroud a mechanical fan needs to be within 3/4" or so of the core to pull enough air, and going longer than 3" on the fan spacer will lead to problems.
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Old 05-05-2010, 01:55 AM
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If the factory was able to make millions of trucks Identical to yours without overheating, it seems like the writing is on the wall. Flex fans are garbage, they take power from the engine to drive, they make a heck of a lot of racket and they aren`t very safe. Clutch fans the factory installed worked as they were supposed to. Since I focus on street machines I stick to factory thermo clutch systems. They don`t use no where near the power of flex fans nor make the noise.
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Old 05-05-2010, 06:26 AM
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Originally Posted by DoubleVision
...Flex fans are garbage...
I can't go quite that far, but two years ago I decided to switch to a flex fan in my '32 pickup (460 Ford) because I wanted something chromed. Big mistake. The very first time I had to idle the truck for extended periods in traffic, it started to overhead. Next day I put the fixed blade fan back on and it hasn't gone over 195 since. So I would second the motion for either fixed blade or clutch fan AND a shroud.

If you've moved things around and can't find a stock shroud that will adapt to your situation (blade half in/half out), shrouds can be fabricated without all too much difficulty. Easiest way I've found is to mock things up with cardboard first then transfer everything to sheet metal.
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