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Electric Fan

bucketkids

Member
I am running (will be) a SB Chev with 4-71 blower. I have an electric fan that I had planned to let run whenever the moter is running. Then someone told me it would be better to put on controls that kick the fan off and on with temperature. I like simple, is it not the thermostat that controls temperature? What is the bennifit of regulating the fan?
 

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There was a time when the mechanical fan ran full speed all the time. Then they designed the temp sensitive fluid coupler that allowed the fan to spin slower than the engine when it was cold. You can run an electric fan all the time if you like. It will take longer for the engine to reach normal temperature and you use a bit more gas [might not even be noticeable].
 
You want the fan to kick off and on to regulate temp you don't want to be running around with your motor running cooler than thermostat.T buckets are not known for running hot usually they run on the cold side.These motors are not even close to working pulling something this light around.
 
I am running (will be) a SB Chev with 4-71 blower. I have an electric fan that I had planned to let run whenever the moter is running. Then someone told me it would be better to put on controls that kick the fan off and on with temperature. I like simple, is it not the thermostat that controls temperature? What is the bennifit of regulating the fan?
An electric fan draws current. If the wire size is not right (too small) you will have a fire. Even if the wire size and fuse is correct, that wire will get warm under constant use. I had mine setup to run all the time and then changed out to a thermostat control. Fan comes on at 200 and goes off at 185.
 
You want simple...just use a cockpit switch to control the fan. Leave it off unless the temp starts to exceed the thermostat rating, then turn it on. I did this for a while until I got tired of watching the temp and added a Dakota Digital fan controller. Set the on/off temps and forget about it.
 
The thermostat is there to regulate flow at a predetermine temp base on temp rating of the wax bulb in the thermostat, and is necessary to first let the engine achieve running temp to reduce emissions, but even fully open thermostat some times under hood and air temp is not enough to cool an engine and that’s where the fan comes in to increase flow across the radiator to do its job of dissipating the excess heat not so critical on a bucket since usually there is no hood to trap hot air but still necessary. For those that say just take the thermostat out don’t do it, the thermostat controls flow and temp and with out there is some circumstances where you could be cooling to much and cause high emissions and oil sludge.
You could just wire a thermostat fan relay controlled by a thermo unit at the manifold runner.
I hope this clear somthing for you. there is alot more to it but in a nut shell this should answer it.
 
I just want to say that reading these replies, it sure seems that most people do not understand what a thermostat's ONLY job in life really is... To make heat, and maintain that setting of heat... A fan on a T Bucket radiator is very much necessary, because air takes the path of least resistance, same as water... It would rather go around a radiator than through it... Outside air blowing on an engine will make absolutely not difference to cooling that engine, only the cooler water in the radiator will cool that engine...
 
I just want to say that reading these replies, it sure seems that most people do not understand what a thermostat's ONLY job in life really is... To make heat, and maintain that setting of heat... A fan on a T Bucket radiator is very much necessary, because air takes the path of least resistance, same as water... It would rather go around a radiator than through it... Outside air blowing on an engine will make absolutely not difference to cooling that engine, only the cooler water in the radiator will cool that engine...

One of my cars (ok... it's a Corvair) has no radiator at all and it cools just fine Ted. :foottap: however you did imply the key word in all this... "movement". air has to flow over a radiator in order to pick up the heat and carry it away. when parked and running, or driving at slow speeds, there isn't enough air movement to do the job. therefor a fan is necessary during those times.
even air cooled engines need this air movement to carry the heat away BTW, so it does help to have "outside air blowing on and engine". :jester:

Stay cool,
Russ
 
Hey Ted, That is why my question is why do we need to turn the fan off and on? The thermostat should be keeping the correct engine temperature, not the fan.
 
is it not the thermostat that controls temperature?

Not entirely. The thermostat restricts flow to provide for quicker warm up. Once open and water's flowing through the radiator, the amount off heat that's dissipated is dependent upon the radiator, and the amount of air flowing through it. The thermostat may begin to close if the coolant temperature gets below it's rated temperature, but the cooling systems capacity is generally sized for the application so that's really not a factor.

Bob
 
Hey Ted, That is why my question is why do we need to turn the fan off and on? The thermostat should be keeping the correct engine temperature, not the fan.
The thermostat makes HEAT, it will not COOL an engine, only the cooler water from the (cooled by air from fan) radiator, will cool the engine, all the outside air (blowing on the engine itself) will not help cool a water cooled engine... only an air cooled engine like a Corvair or a VW:)
 
Hey Ted, That is why my question is why do we need to turn the fan off and on? The thermostat should be keeping the correct engine temperature, not the fan.


Bucketkids,
Think of it like this: if you placed a cover over both sides of the radiator, why would it not cool?? the answer is "because there would be no air flow over the core to take the heat away". when you're car isn't moving, there is no air flow over the radiator either, so you need a fan during those times to provide the air movement for you.

Russ
 
I dont like the fan running all the time because it really is a big draw on the battery. The alt has to work harder all the time. I ran my fan right off the alt no wiring in the car what so ever. No voltage drop no wire to heat up no inside switches to flip. The alt feeds the relay and overload mounted on the fan shroud the temp sensor feeds the relay and thats it. this is my mount and wiring.
 
I dont like the fan running all the time because it really is a big draw on the battery. The alt has to work harder all the time. I ran my fan right off the alt no wiring in the car what so ever. No voltage drop no wire to heat up no inside switches to flip. The alt feeds the relay and overload mounted on the fan shroud the temp sensor feeds the relay and thats it. this is my mount and wiring.

Wondering where you where haven't heard from you in a while. Nice to have you back Great fab work as always
 
... a thermostat's ONLY job in life really is... To make heat, and maintain that setting of heat...
Perzackly. And I don't know about you, Ted, but I've always found more power with more heat. Within reason, of course.

No one could understand why new cars suddenly started appearing in new cars, that last time the government decided it knew more about building cars than the manufacturers did. The Big 3 were all under the gun to increase mileage. So they ran 'em hotter than before.

If you're trying to make horsepressure, you want cool (read: dense) air at the intake and chamber temperatures as hot as you can run them. I think I've said it here before, but start screwing in the timing and taking away the main jet, until it lifts the ring lands. Then, when you're finished rebuilding the engine, take a couple degrees out and stick in a couple numbers of jet before your initial start-up. :nod:

You need a thermostat to slow down water flow throughout the entire system. You want water moving through the block and heads slowly, so it has time to draw heat from the castings. And then you want the water to move slowly through the radiator, so it can transfer heat to the air moving through the core. And you need a fan to pull air through the core. But if it is cold outside, you don't need the fan running like you would if it were 102° outside. And you can wire the fan to a switch, if you know you are good enough to be focused on the temperature gauge enough to turn it on and off as necessary.

Of course, you could look into an alternative means of making power. And Bruce Crower's six-stroke engine looks like a slick way of going about doing it.
 
Thanks putz. I havent seen any pics of your stretch hows that coming . you are gonna love the extra room
 
Body is back on gonna push it back and get some pics later might take it on a short ride this weekend to check it out.
 
Just looked at you post update pics. That extra room will make the ride more enjoyable keep up the good work.
 

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