As I was motorvatin' over the road I wound her up to 6500.......well, the stock '57 4 blade fan pulled the w.p. fan hub forward on the shaft and the fan lunched the radiator. Nice.

So, I have a '69 6 blade clutch fan I'm thinking of using the next time around and my question is should I go with a non thermal type clutch? My thinking is that these spin around 1800 rpm max regardless of engine speed, so there wll be less drag and pull than a thermal type when it locks up? What do you guys think?

(The stock fan, electric fan or a flex fan are out of the question)

FYI: Always mic the shafts and hubs on w.p. re-building kits! I learned an expensive lesson!

FIGHT CONFORMITY! 

Try this Hayden web site for an explanation of their thermal and non-thermal cliutches. In that brand there are four offerings - only one is a non-thermal. http://www.haydenauto.com/Featured%20Products-Fan%20Clutches%20and%20Fan%20Blades/Content.aspx

I found a couple of thermal types that fit the Y-block pretty well - and bought one. Seems to work OK - not a lot of miles on it.

In their catalog look at part numbers #2747 (heavy Duty) and #2797 (Severe Duty). The #2747 will fit a 3/4 shaft and comes with a spacer for 5/8 shaft - the #2797 is for a 5/8. Their "normal" application seems to be for an 80"s Bronco with heavy duty cooling (AC).  

I used one because I wanted to utilize a smaller pulley to jack up the waterpump speed - and when I did, the fan was really wheeling. The inherent clutch slippage seems to deal with that nicely. I'm running a seven blade (aluminum) fan off a Pontiac.

The clutch - especially the "Severe Duty" takes some space - I don't know what you have available, but be aware.    

 
 Steve Metzger       Tucson, Arizona

this diagram shows the dim's of the big severe duty fan clutch (for 5/8 shaft)

Its 1-5/8 from the rear face of the clutch fan hub - forward to the face the fan bolts to and 3-3/4 out over the nose of the clutch

As you can see - even with a 2-3/16 thick fan (measured lying down on a flat face) - the clutch is what takes the room.

t-birds have lots of room so its not a big deal - but the sedans will be different I'm sure.

 
 Steve Metzger       Tucson, Arizona

Philo

You asked about thermal and non thermal fan clutches and stated that you will not consider a flex fan. Why not? I just replaced a thermal clutch fan on a Jaguar with a flex fan. The right thermal clutch fan is heavy and the metal fan is also heavy. On you Yblock even if the thermal fan never exceeds 1800 RPM the fan clutch STILL TURNS as FAST as ever  and this puts a sever strain on the water pump shaft. By using a flex fan and an aluminum spacer on my Jag I reduced the rotational mass by a hugh amount. Flex fans were developed to increase mileage and help emissions ( faster warm up). If your cooling system is in good shape and you have a fan shroud a flex fan is a good choice. You might want to re-think your decision. Pete

I'm not planning on 6500 RPM ( ) but I am planning a Hayden 3619 (19" 6 blade aluminum) and a thermal clutch for my 292 in my 55 F-600!



Cheers,



Rick






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1955 F-600/272/E4OD// Disclaimer: No animals were injured while test driving my F-600 except the ones I ran over intentionally!

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This post was created using OpenSuSE Linux x64 and Firefox

OK Steve really need to know where you got that fuel filter. I really like it, is it set up for a 3/8 line?

Don W.

Philo: A side note on your fan disaster. If your Y-Blk has a relatively stock valve train, ?.. Ford only designed the original stk valve train for max 5400 rpm! The engines power peak was at about 4800 rpm. If you wind it to 6500, you are flirting with disaster!!

Paul

Steve, thanks for the great info. And, alas you're right, Not enough room for a clutch fan in a "sedan".

Pete, Looks like a fex fan is my only option now. I'm running a generator so I don't have the ampereage for an electric fan and don't like the look of them anyway.

Paul, I installed the balanced, blueprinted, Isky cammed +.040 312 this spring so I'm safe. 6500 is my new redline, but will shift @ 6k when I'm "on it"!

My new radiator should be here the first of next week. Thinking of going with the large bearing truck pump with 3/4" shaft and drilling out the car pulley to match and spacing it forward to match the crank and gen. pulleys. I'm wondering if the truck impeller will pump too much water volume as it had deeper "blades"? It will be turning slower than the stock truck setup because of the larger pass. car pulley. Dose anyone have any thoughts on that?

I'd like some advice on which 18" flex fan to buy.  Number of blades, type, brand etc. I'll be running a 3 row copper/brass rad.

Thanks to all,

Philo

FIGHT CONFORMITY! 

I've seen some data that showed no value to the flex fans (as far as reducing HP requirements) - so why give away the cooling capability? Testing (as I recall) showed that when the rev's were going way up or quickly accelerating - the belts slipped more often than not.

I think you would be better off with a fixed aluminum blade style fan - that had relatively low rotating inertia. You can find them with both six and seven blades. 

When I lived in Wyoming - my buddies with trucks that pulled trailers - told me the flex fans were worthless when you had to tach up the motor in second to climb a mountain. Just when you needed a lot of air flow - it was flat.

 
 Steve Metzger       Tucson, Arizona

I have the clutch fan set up on my T'bird to.  It has worked great for many miles and keeps the car cool w/o the excessive fan sound of the flex fan I used before.  MIKE

Mike, still lovin his 57 t'bird after 53 years!