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Hayden fans revisited


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Hi All,

This thread is for "drivers" only. Purists need read no farther, 'cause if you do, there is some back yard engineering here and it's gonna hurt.....

I read with interest the "Tech Tip" by Mr. Loren Naylor, of Liberal Kansas in the March issue of the Bugle, regarding his installation of a Hayden 6 bladed flex fan in his 1936 Buick, model 80. Now I've been thru Liberal in the summer, and it' hot, sticky, and they have bugs.....

The issues we have up here in Colorado are a bit different, in that at 8000 ft. plus, we have no air.... Add to that, the fact that we're either going up hill or down. Now the down is isn't so bad if your brakes are in good shape, but the up part is usually a 5 mile climb, and boy does that take a toll on the old temperature gage. For those who know, I reference Monarch pass on Hwy #50, out of Salida, on the way to Gunnison.

So..... I reasoned that if a Hayden fan would work on a '36 Buick, it should work on a '40 Buick, and I bought one (18" dia) off e-bay @ $36.03 w/ free shipping, (model #3568), for those who follow here.

Yes, they say it won't work for my car, but then what do they know....

Also, this saga is the result of my having to change the fan belt anyway, and again, for those who follow, the correct (new) fan belt is a Gates green stripe, # TO-30506, which was $31.00 @ my local Carquest.

Now on to the "job". Loren's approach was to add a 1/2" spacer, so those big honking blades don't crash into the generator pulley on the first go-round.

After some careful measuring, I had to take a slightly different tack. You see, on a '40 series 90 Buick, there is only 1 3/8" between the front surface of the fan hub and the radiator. That's why they use 1"x 5/16" fine thread bolts.

My approach was to cut 3/8" off the back edge of each blade w/ my tin snips, again so as not to crash into the generator pulley.

Now to hang the pulley and fan with the belt in place in this small inch and three eights gap, I put a dot of white paint on the outside of the pulley where the bolt holes are, and similarly marked the back side of the H2O pump drive plate. Installed a short "stud", which was a bolt with the head cut off and sharpened to a "bullet" shape in the pump disk. Dialed this stud to the 6 o'clock position (down) and assembled the pulley and fan into position via the "pilot" hole and the stud.

NOTE; the stud must be on the bottom, as the Hayden Fan has slots, and on my car, the bolts will need to go in at the very inside of the slots. If you put the "stud" at the top, the fan falls out of position, and you will never find the holes in the pulley or drive disk. Believe me, this cost 2 hours of trials and failure.

With the fan and pulley hanging on the "stud", I then positioned a new bolt (w/ lock washer) into position with a LONG needle nosed pliers, reached thru between the fan blades with my fingers and gingerly screwed the first bolt in a bit, at 180 degrees from the stud. After installing the next two bolts, I removed the "stud" and replaced it w/ a bolt. Tightened all the bolts, adjusted the generator out to tighten the belt, and fired her up. BOY what a breeze !!! Much better now, and w/ a bit of gas, I can see the blades change shape, and start to flatten out. At idle she has about 1/4" clearance from the generator pulley and w/ some throttle it only gets better.

I did go back in and spray paint the blades w/ satin black on the back side as those bright aluminium blades looked a bit out of place.

So...... for you "drivers" who follow, it is possible..............

Best Regards,

Mike in Colorado


Edited by FLYER15015
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I'm sure you were careful to take the same amount of each blade. Like all fan blades one NEVER should stand in its path. I had one come apart on my 40 Ford coupe, went thru the fender, never found the part either. Now that would have HURT....

I wish you well, looking forward to hearing how it does on one of those 5-mile UP HILLS.......

Dale in Indy

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Sorry I did not take pic's of the parts or process. I keep forgetting to do stuff like that, and I have not gotten the hang of "posting" pic's, even though there are posts here about how to do it.

Two nations, separated by a common language......


I used masking tape to guide my cuts @ the back edge of the blades, which are made of 22 gage stainless steel, riveted to the carbon steel fan hub and spokes. I did sand the cut after w/ 60 grit emery cloth and put the small radius back on at the outer edge. I did not however spin balance the prop.

Mike in Colorado

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