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Old 03-08-2018, 03:01 AM   #1
MiraclePieCo
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Mechanical Fan Question

In my penchant for keeping things old school, I'll be using a mechanical fan on my 51 panel with a stock 350 SBC. As you all know, that places the fan pretty low on the radiator - maybe just covering half of the fin area. How about it you mechanical fan users - I see lots of you doing this, so I'm assuming it still must cool adequately?
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Old 03-08-2018, 12:49 PM   #2
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Re: Mechanical Fan Question

I built an ofset fan shroud. Havent tried it yet but its a stock 283 so i dont see any problems
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Old 03-08-2018, 03:11 PM   #3
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Re: Mechanical Fan Question

fan shroud is the trick to getting any fan to work efficiently
and the time to build it is now while you have good access to everything
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Old 03-09-2018, 03:42 AM   #4
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Re: Mechanical Fan Question

Quote:
Originally Posted by MiraclePieCo View Post
In my penchant for keeping things old school, I'll be using a mechanical fan on my 51 panel with a stock 350 SBC. As you all know, that places the fan pretty low on the radiator - maybe just covering half of the fin area. How about it you mechanical fan users - I see lots of you doing this, so I'm assuming it still must cool adequately?
.

.
Why again do you want to run a mech fan.?
Do you also Have the old school foot starter
Generator/Voltage regulator set up
Got your set of ply tires on all four corners too.?

I'm pretty sure You 1951 panel was not stock with that 350

Stop with the "Keeping thing Old school" Nonsense

sure you can make a Shroud to fit that fan on that frame for that motor
or stop the madness and hookup an electric two speed fan
Fan and controller under $75
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Old 03-09-2018, 05:31 AM   #5
MiraclePieCo
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Re: Mechanical Fan Question

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Originally Posted by Softpatch View Post
.

.
Why again do you want to run a mech fan.?
Do you also Have the old school foot starter
Generator/Voltage regulator set up
Got your set of ply tires on all four corners too.?

I'm pretty sure You 1951 panel was not stock with that 350

Stop with the "Keeping thing Old school" Nonsense

sure you can make a Shroud to fit that fan on that frame for that motor
or stop the madness and hookup an electric two speed fan
Fan and controller under $75

My question was not which type of fan I should run. I've built numerous cars using both electric and mechanical fans respectively and I've found the mechanical much more to my liking for several reasons, primarily simplicity and it's cousin, reliability. Too many electric fan failures of thermostats, wiring or motors. And by "old school" I mean 1960s or '70s era technology, not 1940s - no power anything, no electric anything. However I don't want to let this question digress into a mechanical vs electric fan debate; my mind is made up. You build your car and I'll build mine, thank you. If however you have some actual experience with a low fan on an AD radiator and can answer my question, I'm all ears.

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Old 03-09-2018, 08:52 AM   #6
Katrina/10
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Re: Mechanical Fan Question

I put a V8 in my 51 years ago and ran a solid mounted flex fan just like yours. It turned out the same way, with the bottom fan blades below the radiator. I had no fan shroud at all. It never caused a problem with overheating, although I didn't really like the way it looked. I left it that way until I added air conditioning, then went to an electric fan to get better air flow through the condenser while moving slow.
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Old 03-11-2018, 03:49 AM   #7
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Re: Mechanical Fan Question

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Old 03-11-2018, 04:55 AM   #8
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Re: Mechanical Fan Question

Since this thread is now officially degenerating, I'll add this fan experience:

In recent years I built two cars of similar vintage, both with SBCs, tri-power and Mustang radiators. One had a cheapo swap meet flex fan, the other featured a top-of-the-line Spal 16" electric fan with custom aluminum shroud.

Guess which one ran cool and which one ran hot...
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Old 03-11-2018, 08:52 AM   #9
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Re: Mechanical Fan Question

Quote:
Originally Posted by MiraclePieCo View Post
Since this thread is now officially degenerating, I'll add this fan experience:

In recent years I built two cars of similar vintage, both with SBCs, tri-power and Mustang radiators. One had a cheapo swap meet flex fan, the other featured a top-of-the-line Spal 16" electric fan with custom aluminum shroud.

Guess which one ran cool and which one ran hot...
X2

FYI, here is my 34 Coupe, 355 SBC "Mechanical" fan and fuel pump. runs cool in all weather.

I too am a believer in simple is better. IMO more reliable.

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Old 03-11-2018, 09:43 AM   #10
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Re: Mechanical Fan Question

Like was previously suggested, a fan shroud is the answer. Build one that is offset with enough room for air to be drawn down from the top of the radiator and you will be fine, maybe 2" away from the rear side of the fins at the top.

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Old 03-11-2018, 11:19 AM   #11
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Re: Mechanical Fan Question

Speedway has a kit to raise the fan 5". it used a 6 cylinder water pump...
https://www.speedwaymotors.com/Zips-...Kit,58831.html
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Old 03-11-2018, 02:13 PM   #12
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Re: Mechanical Fan Question

That Zips water pump riser kit that Black Sheep showed is a common Small block in a street rod get the fan up where it needs to be piece of equipment. It should let you run a slightly larger fan too.

I've never been too found of electric fans myself. It's not just "old school" it is simplicity and function.
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Old 03-11-2018, 02:49 PM   #13
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Re: Mechanical Fan Question

there is also a medium duty truck set up that used a high mounted mechanical fan set up. just don't remember the application. I did a quick google search but didn't come up with anything. maybe it was a big block thing, can't remember. it would get the fan up in the middle of the rad area for sure. then build a fan shroud that works. here is a tech article from the HAMB that moves the water pump up so the fan sits higher on the rad.

https://www.jalopyjournal.com/forum/...al-fan.168231/

here is a hotrod network version of building your own fan shroud from metal

http://www.hotrod.com/articles/1006s...d-fabrication/

and fiberglass from a different site

http://www.route66hotrodhigh.com/FanShroud.html


this is hotrodding, your truck, do what you like. consider the advice given but do what you want, as long as it is safe for you and everybody else driving on the same roads.
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Old 03-11-2018, 03:35 PM   #14
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Re: Mechanical Fan Question

Hello MiraclePieCo. I had to fab my own fan shroud be cause of all the same reasons you gave above. This is the second shroud I built. The first one just didn't get the job done. I switched back to mechanical to solve my over heating problems. Its a little bit of work but it looks half way decent and works very well. Here is a picture of it done (minus the paint). How I made the shroud can be found in my thread "Just another old truck" by Clarance J in the projects and builds. I haven't posted in awhile so I had to go back and hunt myself down. You will find it on page 4 projects & builds. Then page 14 starting with post 333.

Earl
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Old 03-11-2018, 11:03 PM   #15
MiraclePieCo
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Re: Mechanical Fan Question

I'm not a fan (accidental pun) of shrouds; by covering so much of the radiator's surface they block ambient air flow through the fins when the fan isn't pulling.

For example: a radiator that's 20" wide and 20" tall has a surface area of 400 square inches on it's front side. But on the back side the fan opening for a 16-inch fan is only 254 square inches (3.14x9x9 fan radius squared). THE SHROUD HAS JUST COST YOU 160 SQUARE INCHES OF COOLING SURFACE!

For that reason many custom shrouds have resorted to rubber flaps to allow air flow, like the picture below. Still a poor trade off in my opinion.
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Old 03-11-2018, 11:09 PM   #16
MiraclePieCo
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Re: Mechanical Fan Question

Quote:
Originally Posted by dsraven View Post
here is a tech article from the HAMB that moves the water pump up so the fan sits higher on the rad.

https://www.jalopyjournal.com/forum/...al-fan.168231/
Ha ha dsraven, the HAMB guy really sums it up!

Because I believe that electric fans belong on Japanese cars with fart can exhaust ... and they are NOT needed on a Hot Rod, I will not run a electric fan on my Hot Rods.

And the Street Rodder article was pretty emphatic too:

...even electric-fan manufacturers will begrudgingly tell you that all things being equal a belt-driven fan with a shroud around it is about the most effective cooling option going.

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Old 03-11-2018, 11:11 PM   #17
MiraclePieCo
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Re: Mechanical Fan Question

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Originally Posted by Clarance J View Post
Hello MiraclePieCo. I had to fab my own fan shroud be cause of all the same reasons you gave above.
Earl
Awesome work Earl. That shroud is definitely needed since your fan is so far back from your radiator. And it's relatively open to allow the free flow of ambient air at speed. Nice job!
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Old 03-12-2018, 01:13 PM   #18
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Re: Mechanical Fan Question

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Originally Posted by Clarance J View Post
I haven't posted in awhile so I had to go back and hunt myself down.
nice well built shroud

put your build thread in your signature, read my signature
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