4 blade vs. 2 blade alum. fan
 

Am currently running a 4 blade fan on new leakless pump installed by prior owner with no issues so far. Have read a lot of info. for the 4 blade vs. the 2 blade and some say no increase in air volume past the radiator. Is there any data to support this? Also, the pump has machine bolts to replace the studs/ nuts to the block. Can the 4 blade and pump assembly be removed without removing or tilting the radiator?

Re: 4 blade vs. 2 blade alum. fan
 

I never trust the 4blade - bolt- onto- the -hub-fan having had 2 crack up on me and now only fit the 2 blade aluminium fan. I have sent you a personal message - an article I wrote about cooling and fans on the Ford A for MAFCGB a few years ago.
You can remove the bolt-on type blades easily leaving just he hub in situ on the waterpump without removing the rad. You may or may not be able to remove an entire 2 blade fan and hub and waterpump without removing the rad- cars vary. But you can't remove a 4blader without tilting/removing the rad.... . Do a search of this site for lots of further info on fan/hub/waterpump removal.

Re: 4 blade vs. 2 blade alum. fan
 

You can remove a four blade fan without disturbing the radiator by bending or cutting off one of the blades. I cut off two blades just to make sure!

Re: 4 blade vs. 2 blade alum. fan
 

I've been using a two blade aluminum fan for many years and it performs very well. No overheating.
Rog

Re: 4 blade vs. 2 blade alum. fan
 

I don't know about how much air is moved between the 2 and 4, but my new 2 blade aluminum I installed yesterday is much more quiet.

Re: 4 blade vs. 2 blade alum. fan
 

It's not clear to me, if the 4 blade fan is old, or the new plastic type. But I'm using the new cast aluminum 2 blade type, and it cools fine.

Re: 4 blade vs. 2 blade alum. fan
 

Last fall we had a club member loose a blade on a four blade fan on a tour and it ruined the side of his hood. I think the aluminum two blade fans are the best way to go.

Re: 4 blade vs. 2 blade alum. fan
 

ditto!

Re: 4 blade vs. 2 blade alum. fan
 

There are some tours that will not allow Model A's to participate if there is an original four-blade fan present. Yeah, they're that dangerous. These things are time bombs ticking away until they let loose. It's not a question of "if", rather "when". I am one of many victims, so I know of which I speak. Perhaps an NOS four-blade fan would be o.k., but how many of those are around? Most of use are relegated to using old four-blades with unknown rusting going on inside around the rivet shanks. These things rust near those rivets and then the blades separate. Fortunately, I was driving when this happened to me, so the rocket blade only damaged the hood top panel and the radiator. Had the hood been open while the engine was idling, the flying blade may have hit me. Consider the consequences!
If one's cooling system is so borderline that a four-blade fan is necessary to keep the engine cooler, then there are other problems this Band-Aid is masking. If the engine block's cooling passageways are clear of crusting, the radiator core is good, the ignition timing is correct (not too retarded) and the brakes aren't dragging, the two-blade fan is more than adequate to flow sufficient volumes of air through the radiator and help cool it. If any of these elements are suspect, then a four-blade fan will not solve the problem.
Be safe! Remove that four-blade fan before something horrible happens. Hang it on your garage wall so that the only damage or personal injury it can cause is if it falls off the nail and lands on your toes. Follow the guys' recommendations and order a NEW two-blade fan. Don't trust an original two-blade fan because it's rusting inside, too. Tick, tick, tick...
Marshall

Re: 4 blade vs. 2 blade alum. fan
 

Well said, Marshall.

This topic has been covered here repeatedly over the years; the conclusion is always the same; perhaps a search would have revealed this, and spared you the angst of recalling that scary incident.

"It's not a question of "if", rather "when"

that sums it up for the next search

Re: 4 blade vs. 2 blade alum. fan
 

If you're not going to be original anyway, I'd go with the six-blade plastic fan. I know some on the board say they don't move as much air as a two-blade original or aluminum fan, but it sure seems like they do. In any case, if one of those blades comes loose (doubtful) it's not going to hurt much of anything.

Re: 4 blade vs. 2 blade alum. fan
 

We reviewed the various fans years ago you get the same air flow with the two blade.

Re: 4 blade vs. 2 blade alum. fan
 

I have a four blade on my Phaeton...... now the V8 guys on the other end of this site mostly have four blades and they tour as much as the "A" folks do, these fans are all the same era and they don't speak of having as many issues as the "A" folks.....I understand they do crack and separate etc etc.....but isn't the argument the same for them as well ???

Do the "A" folks just drive their cars a whole hell of a lot more then which makes those four blades more ready to break apart ????

Re: 4 blade vs. 2 blade alum. fan
 

Maybe there is some design flaw with the Model A water pump that puts a little more stress on any fan that is on it? If so the new ones will get fatigue and start breaking eventually.

Re: 4 blade vs. 2 blade alum. fan
 

Here is a study done on the fan blades.

Re: 4 blade vs. 2 blade alum. fan
 

Last year I had fan blade problems on both our '31 Model A, and '31 Chrysler. The A had a clacking noise which seemed to be the timing gear but turned out to be the alum 2 blade fan which became loose on the shaft and enlarged the key way. Quite by accident while cleaning the engine compartment in the Chrysler, I noticed a crack in one of the steel blades on the original 4 blade fan and was lucky it didn't break loose and destroy the hood or radiator.
At the time, every Model A supplier I contacted was out of stock on the 2 blade alum fan so I mounted a 6 blade plastic one from Snyders with the intent of changing back to the alum fan as soon as they were available. I have no cooling problems with the plastic fan and, considering the horror stories about the damage from flying fan pieces, I will keep the plastic one, thank you. I replaced the Chrysler fan with an original because I couldn't find a plastic one that would fit but will keep looking to replace it with plastic and keep the original should we ever sell the car. Broken metal fan blades are really scary. I did not know it was so common

Glen

Re: 4 blade vs. 2 blade alum. fan
 

I get what you are saying. For me, the question was this. Would I use a part on my Model A that I knew had a decent chance of having me lose steering, or even make me lose my brakes? No, because I could injure myself or someone else. Same thing goes for the fan. It may never happen, but it has been proven in can. I wouldn't use a part I knew could seriously injure me. It's one thing to be broken down on the side of the road because of a timing gear, or broken distributor. Those things can't decapitate me.

Re: 4 blade vs. 2 blade alum. fan
 

It is my understanding that all Model A cars originally came with 2 blade fans. So where do these "original four-blade fans" come from? Are they transplants from trucks? Or?

Or am I off base here?

Re: 4 blade vs. 2 blade alum. fan
 

Vince has the story on the four blade fan. http://www.fordgarage.com/pages/model46fans.htm

Bob

Re: 4 blade vs. 2 blade alum. fan
 

TinCup.........can you make those images of the fan study a little larger so we can read them?

Re: 4 blade vs. 2 blade alum. fan
 

Broken fan blades must tend to do more damage on model A's. I had blades break and fly off of my 1949 Plymouth some years ago and it did no damage at all. (other than having to buy another fan) Maybe I was just lucky.

Re: 4 blade vs. 2 blade alum. fan
 

On my '28 Phaeton, I use an original 'Ford-Made' two blade fan, with an inch cut off of each blade. Supposedly this helps reduce some of the stress (weight, centrifugal force, etc.) on the water pump shaft; the reduced length of the over-all fan blade length has not reduced the effectiveness of the cooling. I have been using this original fan for the last 45 years. I suppose it is time to take it off and examine it again for cracks*. If a replacement is necessary, I will use a newly-made aluminum fan blade sold by the Parts Houses. Today's NEW aluminum fans should relieve all of those possible problems.

*It is also of critical importance to thoroughly check (with magnifier) for any cracks or other imperfection on an original Ford-Made two-blade fan. Metal fatigue is the number one culprit in fan failure.

On another note, my '28 Phaeton has both of it's Engine Pans installed, as per factory. This too is supposed to help with the fans cooling of the engine compartment. Also, while Ford did drop the idea in 1929 onward, my '28 also has the factory radiator fan shroud. All of this, I am sure, does some help in keeping the engine cool, with just a two-blade fan.

That being said, on my '31 Dlx Coupe, I have a new six-blade plastic fan and am quite pleased with it's engineering and performance. And just for the historic connection, I have also installed an after-market Fan Shroud on the radiator, as was done on the '28 A's, even though I am fully aware that the conventional wisdom is that they are not really needed. And too, I do have the engine pans installed, as per factory / service recommendations.

Re: 4 blade vs. 2 blade alum. fan
 

Chopping a bit of the fan, I think, changes where the bad harmonics gang up due to the slop in the front bearing.

Re: 4 blade vs. 2 blade alum. fan
 

The 2 blade fan on our '31 CCPU is one piece, no rivets. It's not aluminum, it's either steel or cast iron, (a magnet sticks to it) not sure which as it is painted. It kinda looks like the fan and the pulley are 2 separate pieces.

Re: 4 blade vs. 2 blade alum. fan
 

Doug
Who makes/sells the fan shroud you mentioned?
Thanks
Jim

Re: 4 blade vs. 2 blade alum. fan
 

Jim (Kahuna)- I bought my '30-'31 Fan Shroud several years ago, I don't remember from whom.

However, a quick look at my catalogs of Model A "Parts Houses", shows that Snyder's Antique Auto Parts has them listed on Page 134 of their 2015 catalog. I also found the '30-'31 (and '28-'29) Fan Shrouds on their website: www.SnydersAntiqueAuto.com (their description below):

Model A Fan Shroud
"Originally these were only supplied on the early 28's. Very helpful in optimizing the cooling efficiency of your radiator. Attaches to the back of the radiator and includes mounting hardware. Black plastic construction. Makes your A run cooler. Dimensions: 1928-29, 19-3/4" High, 18-5/8" across top, 18-7/8" across bottom. 1930-31 22-3/8" high, 18" across top and bottom. Hole opening is 16-1/4" for both. U.S.A."
-1930-31: A-8050-301 $68.95 / ea.
--------------------------------------------------------------------------
Jim, please note that these (both '28-'29 AND '30-'31) FAN SHROUDS are made of PLASTIC not steel as were the original shrouds of 1928.
--------------------------------------------------------------------------

If Snyder's does not have them, try MAC'S, who have them listed on page 85 of their "Late 2014" catalog, part # 28-24568-2: $83.50. However, their current website lists them at $94.

Re: 4 blade vs. 2 blade alum. fan
 

This 31' Ford I've got came with a 4-blade fan. To long ago recollection, every other Model "A" Ford owned had a TWO-BLADE and everything seemed to hum along nicely. That present 4-blade fan makes too much wind and sounds like a prop of a DC-3 on warm-up. How much work would it be to swap out the 4-blade and install a TWO-BLADE as Henry Ford intended?

Re: 4 blade vs. 2 blade alum. fan
 

Dog:cool: here,
One IDIOT tole Dad thet if you FLIPPED a 4 blade fan, it wuld BLOW, instead of SUCK! Dad sed the guy needed a BRAIN overhaul:D
Youse Guys are NICE on this THREAD, on that uther one about fans, them guys make FUN of Vermins' 6 blade, plastic fan & I CAN'T tipe Dads' reply here:eek: ur I'll be in DEEP POO-POO:eek:
Buster T.:cool:

Re: 4 blade vs. 2 blade alum. fan
 

I lost a blade from a 59a engine in a 46 ford. Luck was on my side as the blade went out the bottom of the engine/radiator space, cut a lower hose open.
The fan was a standard looking fan but I had never looked it over for cracks.

Best 2-blade aluminum fan?
 

It sounds like the two-blade ALUMINUM fan gets the most votes. Are there more than one manufacturer of the 2-blade Aluminum fan ? Does anyone know who (Parts Dealer) makes them ? If there are more than one manufacturer / source, which is the better ?

At the moment I am still quite happy with my original 87 year old original steel Ford-made fan. BUT after all these many years of service and age, this thread has made me nervous.

Knowing that often times there are a number of reproduction items that have a 'run' made and then the source dries up, I thought I would purchase the best aluminum fan I can get, NOW, and store it up for later use - if needed.

Re: 4 blade vs. 2 blade alum. fan
 

I think only Snyder's make them. That would be my first choice for a replacement if I change out my original 2 blade fan.

Speaking of putting the fan on backwards, shortly after I started working at the junk yard, I told the boss that someone put the loader fan on backwards. It took me quite a while to finally convince him that it won't push much air when it's backwards. Yes, the loader pushes the air forward, rather than drawing it towards the engine, and due to the curvature of the blades, it doesn't work well when it's flipped over.

Re: 4 blade vs. 2 blade alum. fan
 

On the article that Tincup provided. Although difficult as it is to read it does show that the 4 blade definitely reduced temps over the 2 blade for both radiator temps and water temps by a large margin.

Based on the article my vote is for a 4 blade. No, it doesn't look as cool as a 2 blade.

Re: 4 blade vs. 2 blade alum. fan
 

So.....Mikes has a 4 blade fan special....

Re: 4 blade vs. 2 blade alum. fan
 

Call me crazy, but 32 years ago I took the four bladed fan from my 1931 late Slant Windshield 4 door sedan and welded the rivit heads to the blades, welded a bead where the blades Chris crossed and then welded a circular bead between the blades and the pulley. In effect this makes the fan all one piece. After reading all the comments above I now wonder why it has worked so long and on so many long tours. I am not a professional welder so some one clue me in if this was a stupid idea and I should switch to a different fan!

Re: 4 blade vs. 2 blade alum. fan
 

I demonstrate the SAFETY of my 6 blade PLASTIC fan, by putting my elbow to the back side of the blades. It just goes, "BRRRP"!
Bill Brave

Re: 4 blade vs. 2 blade alum. fan
 

I appreciate that they state the results are not scientific but could someone clarify these results for me please. The fan air flow MPH been measured with the car stationary. Thus for example in the 1000rpm table with 2 blader and the car going at 25 mph does the author believe the air is going through the rad at 25 +18 =43mph??? Or does he believe the fan is restricting the apparent wind of 25 mph because the fan is only inducing a speed of 18mph and thus is likely to be interfering with the total airspeed through the rad.

Re: 4 blade vs. 2 blade alum. fan
 

Re: 4 blade vs. 2 blade alum. fan
 

Mike K gave you a scientific reason to your question of was it a stupid idea. My real world answer would be( if God forbid a personal injury was to occur)when the ER medical staff asks what happened (as long as you can still talk) to you or someone helping you under the hood, just tell them you knew about the dangers that's why you welded it but were to cheap to buy a 65.00 replacement fan. Just walking in the ER door will cost more than that, then you have to figure in any surgeries, rehab, loss of wages, etc...
Another scenario, someone inherits or purchases your car but little do they know it's actually a time bomb, then the unsuspecting gets injured.
I hope this help answer your question...

P.s. Just curious how did the fan balance out when you were done ?

Re: 4 blade vs. 2 blade alum. fan
 

I have a two blade, temperature fluctuates from 160-170 depending on outside temperature.

Re: 4 blade vs. 2 blade alum. fan
 

Thanks for the response. Don't know if it was me who posted back then. In that period I was working over seas for a extended period of time and on returning to the US had a hospital stay for quite a while and was not on the Internet. I will look into another fan today.