4 blade fan

[al's28/33]

Here's my question.....

Since the FORD replacement fan 46-8600 was also issued for the '33-34 Model "C" four cylinder cars and there are soooooo may of them around using their original fans, why are "A"s so susceptible to blades breaking off ?????

Is it because Model "A" drivers push their cars to current speed limits and treat 86 year old vehicles like modern cars ?????

[Mike V. Florida]

Originally Posted by al's28/33

Here's my question.....

Since the FORD replacement fan 46-8600 was also issued for the '33-34 Model "C" four cylinder cars and there are soooooo may of them around using their original fans, why are "A"s so susceptible to blades breaking off ?????

Is it because Model "A" drivers push their cars to current speed limits and treat 86 year old vehicles like modern cars ?????

No, it's because of how they were made and the fact they are almost 90 years old.

[Mike V. Florida]

Originally Posted by denniskliesen

I noticed a plastic fan is much smaller in diameter. Are they all like that?

The six blade? Yes.

[Tom Wesenberg]

Originally Posted by al's28/33

Here's my question.....

Since the FORD replacement fan 46-8600 was also issued for the '33-34 Model "C" four cylinder cars and there are soooooo may of them around using their original fans, why are "A"s so susceptible to blades breaking off ?????

Is it because Model "A" drivers push their cars to current speed limits and treat 86 year old vehicles like modern cars ?????

I am thinking the same thing. With a speed doubled, the forces are squared, not by doubled. So, driving at 60 is 4 times the forces as 30 MPH.

[steve s]

Originally Posted by Tom Wesenberg

I am thinking the same thing. With a speed doubled, the forces are squared, not by doubled. So, driving at 60 is 4 times the forces as 30 MPH.

Actually, it is kinetic energy that goes as the square of speed; force (and momentum) is linear.

The problem with the old fans, in addition to poor design of Model A originals, is that with repeated flexing metal "work hardens," becomes brittle, and finally breaks upon further flexing. Bajillions of Model A vibrations eventually do the deed.

I ran an "original" four blade for several years on my A, but when it came time to restore the car I got to remembering all the times when I had reefed on one of the fan's blades to fine tune the position of the timing pin. Sometimes I could feel the blade bend when I was doing this, so, when I was done with the tuneup, I would bend it back so it looked about right--a recipe for accelerating the natural vibrational work hardening. It occurred to me that I was probably not the first one to have done that to my old fan, and opted for more modern replacements. I don't believe that the original propeller fans would bend under this abuse, but I had heard too many scary stories about them.

[ModAfan]

Sponsored Links (Register now to hide all advertisements)

"My recommendation, use a new two blade fan with engine side pans."

What is it that the side pans add to the equation? Do they funnel the air around the engine?

[denniskliesen]

I think the side pans help blow more hot air in around the brake and clutch pedals.

[WHN]

Ideally the side pans allow the air to flow evenly around the engine.

Something like a wind tunel. The air flow goes out the sides of the hood and around and down the back of engine. Without disruption from air coming up from under the car.

Helps with cooling the oil return pipe and carborator.

If it wasn't needed, Henry would not have used them.

[d.]

engine side pans...exactly...they create a path for the cooling air to flow over the engine and exit through the hood louvers, as intended. Otherwise you have no flow and air comes up off the road and mixes with everything under the hood...the side pans are there for a very good reason.

[steve s]

Originally Posted by WHN

Ideally the side pans allow the air to flow evenly around the engine.

Something like a wind tunel. The air flow goes out the sides of the hood and around and down the back of engine. Without disruption from air coming up from under the car.

Helps with cooling the oil return pipe and carborator.

If it wasn't needed, Henry would not have used them.

Originally Posted by d.

engine side pans...exactly...they create a path for the cooling air to flow over the engine and exit through the hood louvers, as intended. Otherwise you have no flow and air comes up off the road and mixes with everything under the hood...the side pans are there for a very good reason.

Have you guys seen any actual air flow data to support these claims? I'm not disputing them, just questioning them. For example, I don't understand why air swirling up from below wouldn't be cooler and more effective than air that's been heated by passing through the hot radiator which would then be carrying the motor's heat back to the motor. Might the pans be intended to reduce road dust in the engine compartment?

[WHN]

There is a reason that the pans were put on these cars.

Dust could be one. However, I think air flow is the most important reason.

Unobstructed air will move more directly and much faster allowing for better cooling.

I have never had overheating problems in any of our Model A's. All have had engine pans.

Think of airplane wings, or even air ducts. Direct the air over surfaces you need cooled.

The great think about Model A's is we all have a view but there is no one left to tell the truth.