Electric fan or flex fan?

[cazsper]

'73 (4v 351c) currently has two 12" electric fans (pullers) with a custom aluminum shroud (came with the car). Putting my hand behind them, they really don't seem to moving much air. On the freeway, my car seems to run at normal temp but when I'm driving around town is when the temp starts to climb (which tells me not enough airflow). I have been told to use a better set of fans and I have been tilde to scrap the electric fans and use a flex fan. My '95 GT had a stroked Windsor with a Vortech making over 550rwhp with just a Fluidyne radiator and he factory fan- and it never ran hot. Any suggestions?

Mike

 

[barnett468]

.

ford lincoln mk VIII or ford contour fans.

i also eliminate the bypass and use a regular thermostat.

if its an ebay rad it might be chinese which holds at least 25% less water than a us made one.

 

[jbojo]

I would first check to ensure the bypass plate is present. The cooling system internal to the motor is different and you need the proper thermostat (one with the hat) and the bypass plate present for proper coolant circulation. I would remove the thermostat and check to make sure its the proper one and that the bypass plate is present.

If they are then:

I would check your radiator to ensure that it has the proper capacity. I am using a BeCool system with dual fans and a 180* thermostat and the water temp gauge barely makes it to the first mark. When I use the computer to display the temp it's at around 185*. Normally only 1 fan is running when the car is idling at 80* outside temp. I think that your cooling system capacity should be around 16 qts for the 351C CJ.

EDIT:

I found a good diagram as to how the 351 C internal cooling works. On the left diagram when the thermostat is closed the coolant from the left and right heads recirculate within the motor when it's cold, going down the bypass radiator.

As the motor warms the hat moves down to block the bypass route so some of the water is diverted to the radiator, center pic.

When the thermostat is fully open then the flow to the radiator is at the maximum to keep the motor cool, the right side picture.

Without that restrictor plate the bypass route would be open all the time so a lot of the hot coolant is being recirculated with in the motor and causing it to run hot.

Hope this helps.

 

[cazsper]

Thank you. The very thing I actually did was replaced the thermostat. I put my finger in the hole and felt the bypass "ring" in place.

 

[barnett468]

Thank you. The very thing I actually did was replaced the thermostat. I put my finger in the hole and felt the bypass "ring" in place.

yes but they are sometime eroded and the parts people occasionally give the wrong thermostat.

 

[cazsper]

I actually just found this on line. Certainly something to look into.

https://www.fordmuscle.com/archives/2006/10/Mark8Fan/

 

[4mm]

I use the same system JBOJO uses and have no overheating issues and I live in one of the hottest cities in the country.

 

[cazsper]

I am certainly going to look into that as well.

 

[turtle5353]

I am running my stock rad, stock fan and stock fan shroud with my 408 stroker and 550+Hp. Never had one issue with overheating or even getting close to too hot. One of the biggest things is making sure you have a good shroud to direct the airflow where its needed. I think the stock components did a very good job of this.

 

[InjectedMach]

Are the fans spinning in the correct direction? Another excellent fan is the police/crown vic/lincoln fan and 99 Taurus 6cyl wagon. The taurus fan is available for about 120 new at advanced auto parts.

I use Afco 2 pass radiators on my builds and never run hot even with ac running in south FL. 427/460/410 all over 550hp.

Flexalite makes and excellent soft start controller if your car is not so equipped - yet.

Keep the electric fans just maybe get a better one, my vote

 

[jbojo]

Are the fans spinning in the correct direction? Another excellent fan is the police/crown vic/lincoln fan and 99 Taurus 6cyl wagon. The taurus fan is available for about 120 new at advanced auto parts.

I use Afco 2 pass radiators on my builds and never run hot even with ac running in south FL. 427/460/410 all over 550hp.

Flexalite makes and excellent soft start controller if your car is not so equipped - yet.

Keep the electric fans just maybe get a better one, my vote

+1

Good point, fan wiring may be reversed.

 

[barnett468]

I actually just found this on line. Certainly something to look into.

https://www.fordmuscle.com/archives/2006/10/Mark8Fan/

thats one of the two fans i mentioned.

i would buy a used one . . the auto store ones are not factory ford [probably chinese]and may flow less air.