Electric fan to supplement stock fan?

[uk-maxie]

My brother and I have been thinking of fitting an electric fan at the front of the radiator to help with cooling when stationary or in slow moving traffic. Quite a simple and obvious solution to an occasional overheating problem, but asking around and looking on the 'net, it appears everyone has a different opinion

So I was wondering if any of the good people in FBBO world have had any success in fitting an electric fan, ideally thermostatically controlled, while retaining the original / stock type fan?

We have a 493 Koffel-built stroker in a 69 Sport Satellite that originally came with a 318. Consequently, we have a 22" rad and no room for a clutch-fan, so we've fitted a (7) blade fan and a shroud that quite frankly could fit better. We know a good fitting shroud is important so we will look at improving this too. We also recently fitted a Flowkooler water pump but we're not convinced it's made much difference.

We have already mounted a trans cooler in front of the rad so there is approx 16"x16" available to fit a fan. We're assuming and hoping a 'pusher' type fan fitted at the front will provide enough extra airflow at slow speeds. Does anyone know what rating (cfm?) we need to be looking at if we still have the stock fan?

Hopefully the pics below show what we're working with. The photo from the front just shows the trans cooler on the right-hand side of the rad.

Any thoughts, recommendations?

Thanks, Rob'n'Stu

 

[Don Frelier]

Hard to tell but the fan looks pretty far inside the shroud?

 

[451Mopar]

I have had better results with the factory style mechanical fans than the aftermarket flex fans.
If the trans cooler lines are plumbed from the trans front outlet port to the radiator first, then into the external cooler and back the the rear of the transmission, then the radiator is doing most of the work cooling the transmission. Swap the lines so the external cooler takes more of the trans heat out and the radiator won't have to work as hard.
With the pusher fan, I think much will depend on the size and quality of the fan.
A cheap pusher fan most likely won't make a difference except that it can run when the engine is off.
Some of the more powerful fans are also fairly deep, but it looks like you have some room without the A/C condenser.
They are also a bit pricy. SPAL Automotive USA IX-30102048 Spal Electric Fans | Summit Racing This one is almost 3-1/2" thick, and costs $172.66
Not sure what condition the radiator is in? A 22" radiator is small for a 493" stroker engine.

 

[Jerry Hall]

Is it the original 318 radiator? And what Don said?

 

[uk-maxie]

Is it the original 318 radiator? And what Don said?

Hi Jerry, no, it's the same spec rad as would have been fitted in a 69 b-body with a 440, auto, no a/c. When we bought the car it had a 22" c-body rad - similar but 'square' top tank (as opposed to round) and the hoses in the wrong corners.

 

[uk-maxie]

Hard to tell but the fan looks pretty far inside the shroud?

Hi Don, do you mean the depth of the fan inside the shroud? I'll see if i can get a measurement this evening but I think it's about the recommended 'overlap', ie about 1/2 way inside the shroud. Will check tho.
I know the shroud doesn't fit that well where it mounts up against the rad. Its mounting face isn't very flat, so has a few gaps, so as I say, we'll look at replacing it with something better if we can.

 

[uk-maxie]

I have had better results with the factory style mechanical fans than the aftermarket flex fans.
If the trans cooler lines are plumbed from the trans front outlet port to the radiator first, then into the external cooler and back the the rear of the transmission, then the radiator is doing most of the work cooling the transmission. Swap the lines so the external cooler takes more of the trans heat out and the radiator won't have to work as hard.
With the pusher fan, I think much will depend on the size and quality of the fan.
A cheap pusher fan most likely won't make a difference except that it can run when the engine is off.
Some of the more powerful fans are also fairly deep, but it looks like you have some room without the A/C condenser.
They are also a bit pricy. SPAL Automotive USA IX-30102048 Spal Electric Fans | Summit Racing This one is almost 3-1/2" thick, and costs $172.66
Not sure what condition the radiator is in? A 22" radiator is small for a 493" stroker engine.

Thanks,
The trans cooler is not plumbed ino the rad as our rad doesnt any connections for a trans cooler. It's just mounted there to get max airflow.
Yeah, I realise the 22" is a bit small, prob too small for a 440 let alone a 493! We should have changed the core support years ago when we had a chance but... hindsight's a wonderful thing.
It was re-cored to the max when we fitted the engine, so it's in good condition and as good as it can be for its size.
Thanks for the link tho, I'll check it out when I can.

 

[ruffcut]

You may try a Flowkooler brand water pump. ruffcut

 

[451Mopar]

Cooling a big block stroker engine is a challenge.
My Coronet (505" stroker) was marginal before adding A/C, and after the A/C install, I had to rethink the cooling system.
The original setup would cool with the A/C off, and even with the A/C on when outside temps were under about 85 degrees.
Outside temps above 85, I would have to cycle the A/C to maintain the engine temperature, but that is when you want the A/C at full blast on 100 degree days.

 

[#41]

Pusher fans just really don't move that much air compared to pullers, but it still may or may not give you just the amount of boost you need. What fan, and if it does the trick, depends on how hot you are getting, how long it needs to run, how it is mounted, etc. The only way to know is to try one out. Pick one with the most flow that will fit your given space. I would consider moving the trans cooler forward if it would help maximize fan coverage of the radiator area.

 

[PurpleBeeper]

When I added two small pusher fans (+ factory fan/clutch), my car idled cool, but began to overheat cruising on the highway (they blocked air flow)

 

[pnora]

What are your actual temperatures that you consider to high?

 

[bobsgtx]

Fan blade depth should be half in/half our of shroud. Seal the fan shroud to radiator with foam weatherstrip and see what happens. All of the heavy equipment and class 7/8 truck I worked on had the shrouds sealed to the radiator. Inexpensive.

 

[Sinitro]

I am running a built 440 with a 22" radiator, clutch fan & shroud. No overheating problems in traffic or open road. U may want to consider that Hayden now makes a short height clutch fan(2 3/4") #2947, my preference rather than hanging some electric fans that draw big current...

Just my $0.02..

 

[uk-maxie]

Hi Don, do you mean the depth of the fan inside the shroud? I'll see if i can get a measurement this evening but I think it's about the recommended 'overlap', ie about 1/2 way inside the shroud. Will check tho.
I know the shroud doesn't fit that well where it mounts up against the rad. Its mounting face isn't very flat, so has a few gaps, so as I say, we'll look at replacing it with something better if we can.

I had a look at the fan / shroud overlap and the back of the fan blades are approx 5/8" behind the back of the shroud. So maybe a bit more than 1/2 way inside the shroud but certainly not fully covered by the shroud...

 

[uk-maxie]

What are your actual temperatures that you consider to high?

Haha.. confession time... we only have the stock temp gauge, in the dash
It's only when the needle goes over to the right, near the double-line at the hot end that we start to worry.
Even if we just had the electric fan on a switch to enable us to bring the temp down when it starts getting hot, that would be a big help. Just need to take the edge off.
Fitting an aftermarket gauge is on the cards too and we may do it in conjunction with the fan... we'll see

 

[pnora]

Haha.. confession time... we only have the stock temp gauge, in the dash
It's only when the needle goes over to the right, near the double-line at the hot end that we start to worry.
Even if we just had the electric fan on a switch to enable us to bring the temp down when it starts getting hot, that would be a big help. Just need to take the edge off.
Fitting an aftermarket gauge is on the cards too and we may do it in conjunction with the fan... we'll see

You might want to verify that reading with the mechanical gauge before wasting time and money on add on fans. You might find the temperature is safe and in normal limits.

 

[MoparLeo]

Cooling system failure is the number one cause of engine failures in the US. And that is with all the factory stuff.
When you increase horsepower on a car the domino effect starts.
Now you have to strengthen (drivetrain) clutches or beef up the a/t, torque converter, cool the trans fluid, drive shaft, u-joints, differential....
The fan is only to cool the engine at idle and low speeds under 40 mph (64 km/h). After that speed the speed of the car pushes more air through the radiator than a fan can.
The modern way to go is increase the radiator size. 26" You need area to dissipate the heat..
Go electric puller type thermostatic switch type fan so as to not block the front of the core.
Move your trans cooler away from the center of the radiator core to allow airflow.
Pressure test radiator cap to 16l psi.(110kPa). 50/50% distilled water to the proper coolant for your car which will depend on if you have iron or aluminum heads/ aluminum radiator.
Run a coolant recovery system like modern cars do.
Make sure your engine is tuned correctly.
All of these things have an effect on the cooling system efficiency.
Use a 195°F (91°C) thermostat.
200-210 °F (99°C-110°C) is not too hot if the system is holding pressure.

 

[33 IMP]

I use a small (10"?) pusher, simply to aid cooldown between rounds. Controlled simply with a switch. I'm using a high efficiency 26" big block Cordoba radiator with a straight drive plastic flex fan, and a slightly modified factory shroud.. i KNOW the fan is eating power..... but it keeps my 500hp 440 cool.
The pusher blocks very little of the radiator, and when its off , the flex fan on the other side will turn the blades of the pusher.