Author Topic: Electric fan temp switch  (Read 2453 times)

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BigBlueIron

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Electric fan temp switch
« on: July 20, 2018, 10:39:28 AM »
Having issue with my cooling fan running all the time. When it does shut off its not for long. Lots of differing opinions on what temp switch should be used with certain degree thermostats. So I thought I would ask here, for more differing opinions!

Turbo 390 in a 50 F1, Champion 3 core drop in fit. (fits great too) Homemade flat shroud that covers entire surface but not as deep as I would have liked it, maybe 3/8" deep. One 14" high flow Spal and one 7.5" Spal. Both pulling. Only running the big fan as it seems to keep up fine, figured only kick the little one if it gets hot. Or thought run it all the time to reduce cycle time of the large one. Really need to add another switch or get a dual temp. Probably a dual temp, I'm out of ports.. Kick the little one in early then the big one is how I would really like it. Kinda like a 2 speed fan.

180* stat with couple small holes drilled for bubbles. Engine does not over heat, haven't seen it much above 200 usually around 190 to 195. Fan switch is 200 on and 180 off installed in thermostat housing. Used a 195 stat for awhile which I'm fine with but I'm trying to drop the temp a little for fueling reasons. (heavy ends in lpg fuel). Hence the 180*

Do I need a switch with a lower range? Say 185 on 175 off?? Need more airflow? I didn't think so since it doesn't overheat. If both fans are on it does seem to help but not much.

afret

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Re: Electric fan temp switch
« Reply #1 on: July 20, 2018, 10:58:31 AM »
I don't use a thermostat but use a Contour dual fan.  I have it set up so one comes on at 185* and the other at 195*.  I also have switches so they can be turned on before that.

thatdarncat

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Re: Electric fan temp switch
« Reply #2 on: July 20, 2018, 11:51:45 AM »
On someone's recommendation I used a PAC 2750 fan controller by Dakota Digital on one of my cars ( the one I took on Drag Week a few years ago ), it's a real nice automatic controller, although it's pretty spendy. A person could certainly just wire the fans with switches & relays, but if you want something with some automatic options & ability for separate fan controls it's pretty slick. Doing separate fans did require purchasing an extra relay. Here's a link:

http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=852/category_id=646/mode=prod/prd852.htm
Kevin Rolph

1967 Cougar Drag Car ( under constuction )
1966 7 litre Galaxie
1966 Country Squire 390
1966 Cyclone GT 390
1968 Torino GT 390
1972 Gran Torino wagon
1978 Lincoln Mk V

BattlestarGalactic

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Re: Electric fan temp switch
« Reply #3 on: July 20, 2018, 01:51:54 PM »
My '69 F100 has 428CJ with stock 3 core radiator(new core 20 yrs ago).  Two pullers, but one is auto, one is manual switch.  Don't recall if I have a thermostat, been so long.  Likely an 180* if it does have one.   Pretty sure I have the 185* switch(don't want it heat soaked too bad before turning on).   The blower car has no thermostat(custom made neck) with same 185* switch with one pusher fan on an aftermarket alum radiator.  They both have no heating issues.  They both have manual over ride if needed.  If you stay moving, the fans don't need to do much.

I've read somewhere recently that some electric fan with too much shrouding actually hinders air flow since the blades aren't moving as fast as the air is being pushed through the radiator at faster speeds.  Thus it holds the heat?  Don't know how much of that is truth?  My '69 does have a full shroud with the fans mounted to it.  The blower car is just a bare fan mounted in front of the radiator so air can move past it easily.

I've thought of the electronic fan controls, as they have variable speed fan control so that it comes on slow and increases as temp increases.  I have not gotten to the point of needing it.
Larry

BigBlueIron

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Re: Electric fan temp switch
« Reply #4 on: July 20, 2018, 04:40:20 PM »
I have looked at the Dakota Digital controller, look like a nice setup, I have a 70 and 30 amp relays already setup would hate to have to redo them.

Battlestar, You just reminded me of that! I remember when making the shroud I contemplated adding a couple shroud flappers but wasn't to worried about it at the time. I think I will throw a few of these on https://www.summitracing.com/parts/spu-ix-30130012/overview/. Can't hurt.

C6AE

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Re: Electric fan temp switch
« Reply #5 on: July 20, 2018, 07:01:58 PM »
I think it is all about where you locate the coolant temperature sensor.
If is located at or near the thermostat, it will always be switching on and off, and if the thermostat is working well it will be mostly on.

When I use electric fan/fans I locate the sensor either at or near the bottom of the radiator, or in the line from the radiator to the block. This is regulating the coolant temperature in the radiator.

(This is the same logic as not placing the thermostat (heating/air conditioner sensor) for your home just above a heating/cooling duct...)

cammerfe

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Re: Electric fan temp switch
« Reply #6 on: July 20, 2018, 10:59:27 PM »
My '63 Effie/390 uses the largest factory radiator available for the truck. When I got it, it had a simple water-pump-mounted fan, no shroud and tended to overheat in stop-'n'-go driving. I put in an electric fan with the sort of 'shroud' that's a ring attached to the outer ends of the fan blades. Just to see how it worked I installed a simple on-off switch. I found that it would to be turned on if I were to be stuck in traffic for any length of time. Turn on the fan and watch the needle drop on the temp gauge. I used it so seldom that I never did change it over to an automatic arrangement.

KS

BigBlueIron

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Re: Electric fan temp switch
« Reply #7 on: July 23, 2018, 08:41:34 AM »

(This is the same logic as not placing the thermostat (heating/air conditioner sensor) for your home just above a heating/cooling duct...)

Great analogy, I might need to weld a bung in the radiator.

My '63 Effie/390 uses the largest factory radiator available for the truck. When I got it, it had a simple water-pump-mounted fan, no shroud and tended to overheat in stop-'n'-go driving. I put in an electric fan with the sort of 'shroud' that's a ring attached to the outer ends of the fan blades. Just to see how it worked I installed a simple on-off switch. I found that it would to be turned on if I were to be stuck in traffic for any length of time. Turn on the fan and watch the needle drop on the temp gauge. I used it so seldom that I never did change it over to an automatic arrangement.

KS


I wanted a mechanical fan with clutch But space constraints wouldn't allow it. Plus I don't want to have to worry about it. Let it control itself so I don't have to be bird dogging the temp gauge.

JamesonRacing

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Re: Electric fan temp switch
« Reply #8 on: July 23, 2018, 12:45:21 PM »
You mentioned you have the "OFF" setting at 180, and have a 180 degree thermostat.  This means your fan will never shut off while running, after it reaches the "ON" temp setting.  I have a 180 thermostat in my truck engine, electric fan, and Holley Sniper injection.  I control the fan relay with an "ON" at 195 and "OFF" at 185.  Going down the road, the thermostat will keep the engine comfortably at 180, but will kick the fan on when idling for more than a couple minutes.  Fan shuts off when the truck is rolling again and has airflow.
1966 Fairlane GT, Silver Blue/Black 496/C4 (9.93@133)
1966 Fairlane GT, Nightmist Blue/Black 465/TKO (11.41@122)
1966 Fairlane GTA Conv, Antique Bronze/Black, 418EFI/C6
1966 F250 C/S, Rangoon Red, 445/T19
1965 Falcon Futura 4-door, Turquoise, EF! Z2363/4R70W