Pusher Fans

[Dan Case]

Originally Posted by Obsessive

Ah yes... Well, according to the recent package that came in the mail from Acton Custom Enterprises today (I'm referring to the very well made reproduction Cobra 427 Chassis Instruction Book), I can speak with confidence when I tell you that the original fans were as follows:

"From chassis CSX.2167 inclusive, a Lucas electric cooling motor is
fitted, Model 3GM with large cooling blades, located ahead of radiator.

The radiator cooling fan is fully automatic and is controlled by a
thermostat switch located in the casting integral with the bottom radiator hose. No manual switch is provided.

427 Cobras are fitted with single or dual electric fans mounted behind
the radiator. Type PES.2379/4. Smiths."

I'm loving all the interesting facts within this book. Too bad it doesn't offer a good location to find the fan motors! In the absence of a time machine, just paint your fan motors gloss black and enjoy your "Smiths" fan motors!

Cooling fans, radiator and engine, for Cobras (leaf spring chassis cars) are fairly complicated because different things were done in different time frames for stock cars. But most cars got two fans, one mounted on the water pump and one in front of the radiator.

The water pump mounted one has been found to be like the one used on some rare big Ford FE engine high performance engine package option sets but without any stamped in markings. The tips of the blades were usually but not always painted a bright yellow.

This original fan has been repainted somewhere in time but chips in the top coat show what the yellow was like. This fan was black, had tips painted yellow, and sometime later was painted over with black again. In the chip site shown there is three layers of paint, black/yellow/black.





The fan in front of the radiator had its own mounting bracket. The Lucas motor is just one of a family of motors with different specific operating and direction of rotation specifications. I only know of one used on Cobras.

[mickmate]

Hi Dan, good shot of the water pump fan. You would know the tips were painted yellow for visibility. That was important as they were supposed to be removed after break in so they shouldn't have been on there after that.

[DanEC]

Originally Posted by strictlypersonl

Peter's original street car has only one fan, but I've found a couple of pictures of S/Cs (and a 4000-series) with dual fans. Who knows the logic or who got what when.

Bob - has ERA ever posted a library of detail pictures of Peter's original car?

Dan

[A-Snake]

Originally Posted by mickmate

That was important as they were supposed to be removed after break in so they shouldn't have been on there after that.

Could be left on in warm climates ;-)

[Dan Case]

Originally Posted by A-Snake

Could be left on in warm climates ;-)

The water pump fan makes a real big difference here in Alabama during hot humid weather during slow traffic or stop light to stop light crawls through congested areas. I have an aftermarket fan behind the radiator because the Ford aftermarket engine oil cooler kit I installed back when I was doing open track events and the stock fan in front of the radiator couldn't be used with the heat exchanger where I put it. (I used existing fan bracket mount holes as I didn't want to permanently modify the nacelle compartment.)


I have driven with and without the water pump mounted fan in all kinds of weather except in snow. I use to remove it during the winter because dramatically increased the time for the complete engine warm up. Now I just leave it on. (Multiple issues can lead to trouble controlling engine temperature so don't assume that management of air movement is the only thing to consider. ) In summer heat without the water pump mounted fan any situation that might lead to long or lots of closely spaced idling periods had to be avoided. The engine coolant temperature would soar fairly quickly. Mid day on a Saturday I would go around town instead of through it.


In summer with the water pump fan installed I can almost forget looking at the temperature gauge. I still look because I manually control the aftermarket fan at the radiator as needed and I still look because once a aftermarket fan motor quit in rush hour traffic in Tulsa Oklahoma on a hot day and my engine got an overhaul as a result. At the last SAAC convention at VIR we sat in line idling a long time for one of the sessions they let large numbers of attendees drive whatever they had around the track in 'touring' groups. My passenger, a long time owner of Cobras and 427 Cobras, could barely believe we sat there idling for so long and the temperatures gauges for oil and coolant didn't rise to dangerous for the engine levels. Once underway, the temperatures resettled down to normal quickly. He said he never had a Cobra or 427 Cobra he could let idle anywhere near that long.


The piece of mind a steady indicated temperature gives was just one benefit. Without the water pump mounted fan there is very little air movement on the top side of the engine. In stop and go traffic light to traffic light crawls the carburetor would get hot enough to boil the fuel inside. When the fuel starts boiling the engine runs poorly. When traffic cleared and we could go for a few miles of cruise speed the engine might leave the last traffic light running like a fugitive from a junk yard. The water pump mounted fan took care of the problem .

[Dan Case]

Originally Posted by mickmate

Hi Dan, good shot of the water pump fan. You would know the tips were painted yellow for visibility. That was important as they were supposed to be removed after break in so they shouldn't have been on there after that.

Whatever the plan was, some Cobras still have their water pump mounted fan blades. Some owners that don't have fans wish they had one if they could find one not on a car that could be purchased. I wouldn't believe how much difference they make if I had not done the testing with and without (sometimes the same day) myself.

[Dan Case]

See how close that red fan and the nut holding it on the shaft are to the fragile radiator?

A not uncommon event is fatigue failure of the steel tab welded to the bird cage tube in front of the engine bay that the upper radiator bracket and gromment subassembly get attached to. The tab jiggles from road vibration, the weld cracks, and it not found and repaired the welded attachment can completely separate. Let the radiator move forward just a little and the radiator can be seriously damaged.