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?