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What do you think of this thinking? (puller fan on FRONT of rad)

vandelay industries

vandelay industries

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What do you think of this thinking? (Installing puller fan on the FRONT of radiator) Pt. 1

Background:

1) 262 v-6 (less cubes = less friction = less heat etc., but you already knew that.......)

2) i have an 16" Spal electric puller fan on the back of the radiator (This is a stock v-8 radiator BTW). i only need to use this fan in traffic/traffic jams so i've probably only used it 10-15 times MAX over the past 3.5 years. Fan is completely not needed if traveling faster than like 21mph.
i have not had a mechanical fan for 3.5 years with no problems.

Since the fan is only used in stopped/or very slow moving traffic, would putting the PULLER fan (not pusher) on the FRONT of the radiator be a good idea? Hot air would be pulled OUT of the engine compartment vs. pulled into the engine compartment?

3) In addition, i have/had a fuel percolation/vapor lock issue that could actually be solved without touching the fan (by re-routing the fuel line and/or adding a return line), but would this fan idea help irregardless?
 
I don't think it's a good idea. It may not be needed now, but assuming the fan can pull a good amount of air, it gives you a margin in case things don't go as planned.

As my last radiator plugged up, the ambient temp and load required to get coolant temp to hit the fan "on" temperature while moving at freeway speeds slowly decreased. And even at freeway speeds, my single electric puller fan was able to keep the coolant temps in check. The fan stayed on for longer and longer periods of time as the radiator got worse, but it still never allowed it to overheat.

That might be an extreme example, but had I a puller fan, that would have been more than just an inconvenience in circumstances I found myself in.

Like you, I ran the truck around without a fan for a bit just to test, and with a good radiator, above ~25MPH, I didn't need a fan. BUT, that was in moderate temps, new radiator, and on flat ground with no extra weight.
 
The whole point of a radiator is to get the coolant temp down. Pulling hot air out of the engine bay won’t bring the coolant temp down as good as the ambient temp. Since the coolant is closer to the combustion chamber, I would think that the engine would run cooler as opposed to having warmer coolant and cooler exterior of the engine.
 
rampage said:
The whole point of a radiator is to get the coolant temp down. Pulling hot air out of the engine bay won’t bring the coolant temp down as good as the ambient temp. Since the coolant is closer to the combustion chamber, I would think that the engine would run cooler as opposed to having warmer coolant and cooler exterior of the engine.
Click to expand...
Good point....
 
Also the way the air flow is, it's going to be easier to get cool air into the engine bay from the front, than pull it from under the truck.

Ignoring the cited issue of pulling heat through the radiator.

If you have a good fan, even at idle you will feel the hot air coming out under the doors.
 
The best way to eliminate fuel percolation/vapor lock is to install an electric fuel pump. I had this problem pretty bad on my 1952 Dodge coronet.
Inline six 230ci flathead.
Mechanical fuel pump. With heat shield added
Original 4 blade mechanical fan.
New aluminum radiator
All new fuel lines, gas tank, rebuilt carb with a phenolic spacer and heat shield under it
Re routed fuel lines. Even tried wrapping them with heat wrap.

All of this wasn't enough on 90+ degree days and stuck in traffic. The car has a small grill opening and the idle on these engines is very low, like 450 rpm.

I changed the exhaust and put on a tube header with dual outlets. It hit the mechanical pump so that got removed and an electric pump was added. I've never had a percolation/vapor lock issue since
 
Some brush-type fan motors are reversible, but many blade designs work better in one direction. I used to go to this festival where you had to idle through a crowd for like a mile to get to camp and had time to dream up a reversible fan setup. It was always baking hot and humid there and pumping the engine heat out in front would probably have looked like parting a sea.
 
I think that I would work if your backing up,,if your moving forward then you driving back in the heat that you just made,once you get going then you are fighting the fan.
 
vandelay industries said:
What do you think of this thinking? (Installing puller fan on the FRONT of radiator) Pt. 1

Background:

1) 262 v-6 (less cubes = less friction = less heat etc., but you already knew that.......)

2) i have an 16" Spal electric puller fan on the back of the radiator (This is a stock v-8 radiator BTW). i only need to use this fan in traffic/traffic jams so i've probably only used it 10-15 times MAX over the past 3.5 years. Fan is completely not needed if traveling faster than like 21mph.
i have not had a mechanical fan for 3.5 years with no problems.

Since the fan is only used in stopped/or very slow moving traffic, would putting the PULLER fan (not pusher) on the FRONT of the radiator be a good idea? Hot air would be pulled OUT of the engine compartment vs. pulled into the engine compartment?

3) In addition, i have/had a fuel percolation/vapor lock issue that could actually be solved without touching the fan (by re-routing the fuel line and/or adding a return line), but would this fan idea help irregardless?
Click to expand...
Yeah no.
The reason most of time you don't need the fan is because the radiator is exposed to air when you move.
You put the fan in the way and it reduces the air and you run the fan against the wind and you burn the fan.
Next.
 
The only time a pusher fan should be used is when you don't have enough space for a puller fan. Otherwise, always use a puller fan. My brother had no choice on his 1951 Dodge M-37 military truck. It has a 650hp BBC and a very large custom made radiator. There's like 2" of space between the radiator and the pulley
 
I worked at a coffee distribution company years ago.
We had a fleet of gas powered box van delivery trucks.
One of those trucks had a catastophic failure of it's water pump at highway speed.
Destroyed the radiator, fan, and pump itself.
To save money, the boss had the yard dog replace everything with junkyard parts.

The truck idled fine but overheated above 30 mph.
They spent a week trying to figure it out.
Until one day someone was leaning into the engine compartment and someone else noticed his company shirt was flapping in the breeze created by the reverse pitch fan!
Yes, he tried flipping the fan.. still reverse pitch.

Moral of the story; go with the flow.
 
If under hood temps are causing you issues with high heat and vapor lock the best solution I have found is installing hood louvers. The fan is moving air but there is nowhere for it to go. I have seen vapor lock occur when the electric fans are cycling on and off properly. Coolant temps are ok but under hood temps are still too high. Look at the roadkill guys, always taking the hood off.
 
muddermilitia said:
The only time a pusher fan should be used is when you don't have enough space for a puller fan. Otherwise, always use a puller fan. My brother had no choice on his 1951 Dodge M-37 military truck. It has a 650hp BBC and a very large custom made radiator. There's like 2" of space between the radiator and the pulley
Click to expand...
He wants to put a puller fan on the outside.
 
HankScorpio said:
If under hood temps are causing you issues with high heat and vapor lock the best solution I have found is installing hood louvers. The fan is moving air but there is nowhere for it to go. I have seen vapor lock occur when the electric fans are cycling on and off properly. Coolant temps are ok but under hood temps are still too high. Look at the roadkill guys, always taking the hood off.
Click to expand...
Running without inner fenders might help too. Then you aren't cutting into your hood
 
Thanks all for the input.

My original intention was, since i, apparently, only need to use the fan in traffic jams or very slow moving traffic, to use a puller fan to pull air to the OUTSIDE of the engine compartment rather than INTO the engine compartment. Foward speed wouldn't be an issue here, so i'm thinking it would work air-flow wise---there wouldn't/shouldn't be any turbulence? However, i forgot that the air flowing thru the radiator would be HOT underhood air, much hotter than the cool outside air. So, generally the idea won't work.

Also, if it was such a good idea, the factory would h......

However, in the interest of being neurotic and exhaustive, i do want to show you an underhood pic (as soon as i can find one) to illustrate how much space i have between the radiator and engine to get further commentary on this puller fan concept. Remember, this is a 4.3 v-6; i can and do literally stand in-between the rad and engine when i'm working on it. Also, keep in mind the 73-77 monte carlos and grand prixeses.

Also, my fuel perc/vapor lock problems can be solved by re-routing the fuel lines. The line is an aftermarket, non-stock braided line type that is in close proximity to exhaust manifold and to heater hoses. Installing a return line and using heat sleeves, heat shields where appropriate. Louvers would be cool, but i don't know how.
 
At a standstill, it's less efficient. If you're moving 5-10 mpg, the air stalls and it's like not having fans at all. I've accidentally wired fans backwards and it's night and day between problem and solution, you want the air going back with a puller fan.
 
I have known a person I knew,who used a serpentine water pump on a standard belt driven motor who constantly had heating issues. Pump rotated the opposite direction not moving water fast enough.
Look into that and or a higher volume water pump. Thermostats are different also. I've seen some that flow too fast not alowing the radiator to hold onto hot water long enough for the fan to cool it. Radiator caps can be problematic. For almost a year I fought an overheating issue in a freshly rebuilt BBC and it took an old shuffling mechanic at an out of the way gas station to immediately diagnose my problem. Radiator cap. Yep. It happens. Just food for thought.
 
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