Thread: Advice on fan

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I've got a 39 Chevy, what do you think on the fan. I've got a 350 an I have been told that on Chevy you have more room an mechanical would be better than electric.

What do you think.

Depends on how well your 350 fits in there....Usually, the fan ends up being too low in the frame, so an electric is the easier way to go.

Hartside I had the same problem with my 37 chevy. The engine sat to low and I only had about 3" from water pump to radiator, so I mounted two electric fans on the front of the radiator and set them to push the air. The only time they come on is if I have to sit in traffic for awhile then when they do come on they run for about 20 seconds and bring the temperature back to 170 degrees

Hartside.--Due to space allocation if forced to use an electric, opt for a puller fan if at all possible. Efficiency.
SPAL makes a puller fan with a face (radiator side) to rear of electric motor, 2 5/8 inches, 2350 cfm.
As Richard has stated, shroud as best you can.
Good luck.

Hartside,
I also have a 39 Chevy 2-door sedan. I am riight in the middle of this same dilema. After mounting a Vintage Air frontrunner bracket set-up, I have exactly 3" between the water pump pulley and the radiator face. I have looked at lots of possibilities to solve this and would be happy to forward directly all the correspondance between myself and some people with lots of experience in cooling.
The bottom line right now for me is Flex-a-lite has a dual low profile 12" fan & shroud that is 2 5/8" thick. They say it pulls 2500 CFM but is only rated at 19.5 amps. I think it would take 20 amps to do this so it might be over-rated in CFM's. The other possibility is as suggested above and use a pusher fan setup. Spal makes a 12" setup that uses 2 fans and should push something like 3500 CFM's. The mechanical fan is too high but I am going to be about 450 HP and am concerned about heat. I might use a mechanical fan plus the dual 12" pushers.
I will let you know in the next few days. Still researching.
MikeC

An average mech fan will pull 5,000 cfm,you need 3,500 cfm for a v8 w/o air if you drive in traffic.
A 39 chev is hard to cool because of the space restraints. Because of this I would go w/the most efficient radiator available which, will be made of alum.
Do not put fans on both sides of the radiator & keep in mind that a puller is more efficient than a pusher.
Don

Don You stated that a puller fan is more eficient than a pusher and my thinking is it because your pulling the hot air from your engineinstead of pushing the hot air back over the hot engine? That makes alot of sense but when I instlled my dual electric fans in my 37 chevy truck I origionally had them set to pull but for some reason wwhen sitting in traffic and they came on they would run about 40 seconds to cool the engine down. When I reversed the fan direction and had them push the hot air over the engine, thay would only run 20 seconds before they cooled the engine down. Now the 37 chevy has side vents which I still have and was wondering if that made a difference.

I havent had too much experiance with cooling, but what if you placed two fans at an angle outward and slotted the fenders? or is it firewalls? Either way, if you put two pullers outward and away from the engine, it seems to me that it would be a cross draft system along with the radiator cooling. Just speculation.

I hate to cross forums but there is a great tech article on another forum written by Steve Jacks. I am not trying to create any ill will. This is a great article and will answer many of the questions here and I don't want to plagerize someones work.
http://www.streetrodstuff.com/Articl...g_Suggestions/
In order of the article, the top cooling suggestions are;
1. Aluminum radiator
2. Lowest % of antifreeze that you can get away with
3. Highest tested pressure cap
4. High flow water pump
5. Don't use under-drive pulleys
6. Run manifold vacuum advance
7. For carbed engines; tune the carb
8. Always run a fix blade mechanical fan w/ clutch and shroud
9. Don't use metal coatings on radiator hoses
10. Proper ventilation of engine compartment a must.

Steve writes for Southern Rodder and has done a lot of research on cooling.

Has anyone used or seen the Mattison offset fan motor.

http://www.streetrodderweb.com/hotne...sr_technlolgy/

Allright, thats a cool looking design, but how well does it work?

Originally posted by mikec
Hartside,
I also have a 39 Chevy 2-door sedan. I am riight in the middle of this same dilema. After mounting a Vintage Air frontrunner bracket set-up, I have exactly 3" between the water pump pulley and the radiator face. I have looked at lots of possibilities to solve this and would be happy to forward directly all the correspondance between myself and some people with lots of experience in cooling.
The bottom line right now for me is Flex-a-lite has a dual low profile 12" fan & shroud that is 2 5/8" thick. They say it pulls 2500 CFM but is only rated at 19.5 amps. I think it would take 20 amps to do this so it might be over-rated in CFM's. The other possibility is as suggested above and use a pusher fan setup. Spal makes a 12" setup that uses 2 fans and should push something like 3500 CFM's. The mechanical fan is too high but I am going to be about 450 HP and am concerned about heat. I might use a mechanical fan plus the dual 12" pushers.
I will let you know in the next few days. Still researching.
MikeC

I am running dual 11" spall fans that are a one piece unit with rubber flapps that will open as the cars goes down the road and there is more aircomming in my natural forward motion. these fans draw 13 amps each and move a claimed 2700 rpm. So far so good and the fans rarely run with the preset 185 degrees stat.. Truck has only been on the road 3 months. I run a Griffin radiator that I don't recommend the ends are epoxied not welded, not a good idea if it need repair. Ed ke6bnl

Ed,
Are the dual fans pushers or puller?
MikeC

Pullers and pushers

I'm not sure everyone understands what that means. So, just incase, air should always flow through the radiator from front to back. A puller fan is mounted behind the radiator and sucks or pulls air through. A pusher fan is mounted in front of the radiator and pushes air through. I have both in my car, the puller fan comes on at 190 degrees, the pusher fan is mounted in front of the A/C condenser and comes on when the A/C is turned on.

You do not want to set up a fan to move air from rear to front for a couple reasons. First when going down the highway air is pushed through the radiator by ram effect, having a fan blow the opposite direction would stall the air and the increased resistance could burn out the fan. Secondly the fan would be trying to cool the radiator pulling hot air from the engine compartment instead of cooler air from outside.

Your electric fan should be controlled in such a way that it is normally off when going down the highway so as not to interfere with the ram air being pushed into the front of the car.

I have also read the articles that Mikec referred to and they are excellent.

Pat

Originally posted by mikec
Ed,
Are the dual fans pushers or puller?
MikeC

The fans are pullers and they amped out at 13 amps each and I run a power master alternator that puts on (I measured) 79 amps at ideal and 110 at cruising speed. I ran the truck with out the front end when we made our first test drive and it was cool to see the rubber flapper letting the extra air expel to aid the cooling with fans off and car going about 30 or mph. Ed ke6bnl