Radiator Fan

[BBM3]

What was the original question?

Will this fit my....
This has been an interesting conversation to which admittedly I added some BS.
However....
All blame for off topic banter falls entirely on HAULIN IT and his hilarious "Fred the Fan Man" rant.

[LTZ C20]

This is the stock, original fan off my buddy's 79 GMC K2500 High Sierra. It is exactly the same as the fan off my old 79 Chevy C20 Camper Special.

My truck came from the factory with a 4 core radiator, sb 350, turbo 350 and ac.

His truck came from the factory with a 4 core radiator, sb 400, turbo 400 and ac.

[enaberif]

Perfect. The pitch is completely different and gives me a good perspective.

Apparently clockwise fans tilt towards the left and counter fans tilt towards the right.

[fxrsrider]

Here is a quote from the GM 1973 CK service manual:

"Automatic fan clutches, Figure 6, are hydraulic devices used to vary the speed in relation to the engine temperature. Automatic fan clutches are used with many engines, especially those equipped with factory installed air conditioning units. Automatic fan clutches permit the use of a high delivery fan to insure adequate cooling at reduced engine speeds while eliminating overcooling, excessive noise, and power loss at high speeds."

Fan clutches are great.  They make for better fan efficiency and motor performance, no doubt.

For the record, some of the earliest automobile fan clutch patents go back to the mid-late 60's.  By mid 70's nearly every auto company was applying for fan clutch patents....electro-magnetic, viscous, electro-viscous, electric, etc. fan clutch patents were being applied for....and still are well into 2015.  None of the early patents speak of "overcooling" as a problem with internal combustion engines and none seek to solve the "problem" of overcooling.  Every one of the patent applications (including those filed in the 21st century) seek to produce a more efficient cooling component in the engine (i.e. the fan).  The myriad inventors of the fan clutches (including GM), all discuss the loss of HP when a fan that is directly connected to the water pump pulley and in constant motion and is forced to wrestle against incoming air, particularly at increased speeds.

1.  If a fan without a clutch is inefficient but "overcools" anyways....it logically follows that by adding a fan clutch, and therefore producing a more efficient cooling mechanism, then the clutched fan would "overcool" even more.
2.  I suppose then, all of the GM autos made before the invention of the fan clutch just simply, never heated up. Thank you Fred the Fan Man....you saved the world of autosports and made driving possible.
3.  Despite what the holy grail service manual says...I doubt that "overcooling" was a problem that GM ever had with the sbc 350.

[rich weyand]

SBCs tend to run cold, BBCs tend to run hot.  The issue with the SBC isn't having it run cold in hot weather, obviously.  The issue is getting it up to operating temp when the ambient is (in my case anyway) below about freezing.

[LTZ C20]

Perfect. The pitch is completely different and gives me a good perspective.

Apparently clockwise fans tilt towards the left and counter fans tilt towards the right.

Welcome. I felt for ya a little cuz we have the philosophy of the fan goin on here and no one yet had posted the pic you wanted. So figured I'de help ya out.

Now we can get back to the movie "Fanology". Lol

[blazer74]

Mines a 7 blades and is slightly staggered. 
Pictures are the best I could do without removing the fan.




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[enaberif]

That is perfect. It again shows clockwise fans tilt towards the left not the right!

Thanks man.

[blazer74]

Welcome


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[enaberif]

Found a nice 6 blade today at the wreckers. Gonna be installing it in a few.

So I need a few more answers to things. I need some much needed measurements to now check and see if my rad shroud is proper size.

I measured the ID of the shroud for the fan blade and got 21 3/8"
I measure the depth of the fans shroud and got 5 1/2"
I measure the amount of blade sticking out and get 1"

I also have a 4x4 with no AC if that might make a difference.

Part # 6264137

[bobcooter]

That little fan in the first pic looks like may be for a 6 cylinder. Never seen one with such stubby little blades before on a V-8. The 6s were a smaller diameter. 

[enaberif]

So just thought I would update this thread.

With the new 6 blade fan, new hayden HD clutch fan and heater core I am unable to get my truck to proper temp

This is frustrating..

[LTZ C20]

Thermostat? You can have all the great cooling stuff in the world, but if your thermostat is stuck or not working, it's never gonna warm up.

[enaberif]

thermostat was replaced and tested before. the only way I have yet to see this truck warm up properly is without a fan.

[Don5]

Did you put the 180 degree thermostat in it? If you put a 165 degree one in it will never blow hot air out of the heater. The coolant will circulate too fast at a low temp.