Thermo fans

[pedro]

I'm ready to buy thermo fans for the wagon now and I seem to recall someone saying twins would be best, could anyone give me a bit of advice on the sizes I'll need and the best brand to get.
                  Pedro

[FC427]

Pedro I use to run two 12" was told these were 1200 CFM  Davis Craig's on my blown engine with a large custom aluminium radiator  and did not cool ,I changed to one 16"  ICE Brand  2800 CFM and it worked cooling it ,fitted one when I built MR FC and it cooled the V8 easy.... others may have had success with smaller fans  ......FC427.....

[jack_fc]

Pedro, I ditched the Davies Craig fan on mine and replaced it with an ICE brand, same size - immediate improvement...
My (limited!) research indicates that for most radiators (probably other than wide but not very high ones) one large fan is better than 2 smaller ones.
Several years back, there was an excellent thread by Ed regarding fans, shrouds etc addressing cooling issues with his maroon wagon. Maybe Ed or someone else can direct you to this thread; I found it extremely informative.

cheers, jack

[EffCee]

Pedro,

No matter which way you go, ie one larger fan or two smaller fans, to get the best reults you will need to make up a shroud to ensure that air is drawn the the entire cooling fin area of the radiator. From this point it will be a matter of checking the ability of the fans capability to move air. As Mark has said he had a twin 1200cfm that did not provide sufficient cooling, however the larger single was capable of moving 2800cfm of air which solved the problem.

By ensuring that the fan is shrouded it ensures that the air flow is across the total cooling fin area, ensuring that there are no hot spots in the radiator.

Keith

[Ed]

Hi Pedro,
Thermo fans and cooling. Basically biggest is best.
A big single will cool more effectively than multiple smaller fans.  
The swept area of the blade on a larger diameter fan will move more air
ie If you think about the blade tip, the larger radius =  further distance travelled = more air.

If you are lucky enough and can run a shrouded engine fan, then that is the best option.  If you can only fit front mounted thermo, then go the biggest one you can fit in there even if it overhangs the core in some places.

Here is a thread with some research I did on cooling.  This car can sit in a traffic jam on a 40 degree day and not overheat.  It uses a single pass brass, 4 row radiator. The “high flow” thermostat was a great investment, but the combination of all the items made it work.  

http://fefcholden.org.au/forum/index.php/topic,12243.0.html

Cheers

Ed

[FCRB26]

I fold up a shroud and cut holes into the shroud for fan or fans works well as it stands the fans off the radiator which is always better than bolting to the core which loses flow.


i have found a single is better than twins.

Repco $130 something from memory.


Pete

[pedro]

Thanks for all the input guys, Your post was excellent reading and very informative ED, looks like a big single fan and shroud is the go.
                     Pedro

[FCOV6]

Ford twin fans with shroud is a popular fit and may be about the right size, think they are off AU and other fords.

[NosFEratu]

Pedro

We are using a VK V8 radiator which looks like it is about the same as yours except we have sumk it below the radiator support panel.  It has a single rear mounted 16" Davies Craig fan which is actuated by a thermo switch (through a relay) that screwed into the standard Commodore tank.  There is no ducting but the fan is mounted as close as we could to the raidiator.  We have no overheating issues.  It has to idle for about 10 -15 minutes before the fan comes on.  It only takes about 1-2 minutes for it to reduce the temperature and for the cycle to begin again.

From my experience always put in as big a radiator as possible which you certainly have.  A four core brass/copper radiator may not do a much better job than a 3 core as its bloody difficult to get air past the forth core.  As noted before big diameter thermos have better flow than twin little jiggers (they a just a bit bigger than the twin bees dick fans).  Oh yes make sure the air has to go through the raidiator not around it.

Now for a funny story.  Went to Bright rod run last year.  A friend of forum member (who will remain nameless but you know well) bought his mega dollar 55 Chev sport coupe with 572 big block which was just finished.  Unfortunately, there were a few teethiing issues and it couldnt do more than 100 kph on the way up without overheating.  It had a huge alloy radiator, twin thermos with beautifully crafted alloy fan ducting but is still overheated.  Being an outsider it is always easy to criticise but sometimes you see the obvious.  The sheet metal panels on each side of the radiator had been removed  and replaced with what looked like alloy that had Chevy symbols laser cut into making it more like mesh.  Looked fancy but they would have let the air straight past without going through the radiator. In addition, standard sheet metal bracing around bonnet lock had been removed so the air could go straight over the radiator. This was a great car and I dont know if these were the "real issues" but I am sure they would be fixed by now.

regards

Alfred the Bulter (John)   

[FCRB26]

Ill make you a shround cheap cheap just PM some dimensions of the core and bolt holes and size of cutout and ill whip one up out of 2mm sheet.

[pedro]

Thanks for the info, FCOV6, Alfred , I'll take you up on that offer Pete I've been very happy with everything else you have made for me, I'm not sure when though as we are moving soon and at the moment everything is up in the air, and I have to just take one day at a time for now.
                 Pedro

[FCRB26]

No worries.

[pedro]

Anyone know who sells the ice brand fans i can't seem to find the company on google, just copied this from the davies,craig site their fans seem a bit cheap and plastic looking though.
  Pedro


Question No. 3
Can the Davies, Craig Electric Fan be installed in front of the radiator as well as in the engine compartment?
Yes. Davies, Craig electric fans work equally as well in either position. The instructions show how to install the fan blade and reverse the wiring to accomplish this. The fan blade must always turn in the direction of the arrow on the fan hub. Also always follow the instruction “This side must face front of vehicle”.
 
Question No. 4
Is there any advantage to having two slightly smaller fans as opposed to the one larger fan?
One of the very important factors with engine cooling fan/s is the volume of air any specific Thermatic Fan can pull or push through a radiator. In general terms 2 x 14" fans will match the volume flow of 1 x 16” fan but not 2 x 12" fans. There are other factors including core thickness and clearly the thicker the radiator core a more powerful fan is required. Therefore a single 16” fan will out-perform 2 x 12” fans in almost all situations. E.G. If your radiator is 4 core or greater then 2 x 12" fans wouldn't be recommended. Therefore 1 x 16" fan could be sufficient.
Remembering that any Thermatic Fan will cease to be effective once the vehicle speed has reached 50-60 KPH after which the ram air takes over. We also recommend Thermatic fans be fitted to the downstream (engine side) of the radiator

[FC427]

Pedro my local spares shop ordered me a 16'' Ice fan a couple of years back  also ADC  sells them .. always check amp draw in the fans specs as a lot advertise there fans at  2800 cfm but would be closer to 2000 cfm with the amp draw ..I have always had much better results with one larger fan over two smaller ones [still have the two 12'' Davis Craig  fans that would not cool my ute] ......FC427.......

[hsv-001]

Am i correct in my beleif that any fan only becomes a restriction to cooling when the vehicle is at speed.So with this in mind coolant capacity and airspeed through the radiator when standing or at low speed is the issue.With my vehicles i question my local radiator shop regarding capacity before going on ebay and when i have the largest rad and fan combo possible installed i then buy an inline thermostat and variable switch so i can set the temp that my thermo fan kicks in.If the motor wont cool enough sitting running in the shed it will overheat in traffic.

[FC427]

Pedro my local spares shop ordered me a 16'' Ice fan a couple of years back  also ADC  sells them .. always check amp draw in the fans specs as a lot advertise there fans at  2800 cfm but would be closer to 2000 cfm with the amp draw ..I have always had much better results with one larger fan over two smaller ones [still have the two 12'' Davis Craig  fans that would not cool my ute] ......FC427.......

Should have added your 16'' electric fan with curved blades should draw around 25amps to get your 2800 cfm and straight blade will draw 20 amps to make 2000 cfm  of course this will be  bit different between  manufactures,, '' Be Cool '' also make a great range of 12volt fans  ......FC427.......

[pedro]

Thanks guys, one large fan it is, I was just a bit puzzled that i couldn't find any reference to the Ice ones anywhere on the net, I'll try the local spares shop over in Beaudesert.
  Pedro