Sometimes Older is Better

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nm9stheham

nm9stheham

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My son and I wanted to replace the old Mopar metal fan that was cooling OK with something lighter, to get rid of the some of the HP load and low RPM belt loads. We could not fit a new nylon Flex-a-lite fan and still clear the Sanden type AC compressor clutch because the blades are so deep.

So I noticed my old 70's fiberglass Flex-a-lite fan hanging on the garage wall, and decided to clean it up and try it out. Dang.....it cools 5-10 degrees better than the 7 bladed Mopar fan on a 1000' steep climb on Afton Mtn! And it's Hemi-Orange!

This fan was on my old Ranchero for years and I ran that engine all the time to 6500 RPM and put over 50k miles on this fan. No cracks or anything; just some surface rust on the rivets. I see a few of these on eBay; now I need to see if there are any new ones like this around. Of course, this was made in the USA, not China, so with a new one, YMMV. I see that Flex-a-lite has stainless bladed ones nowadays with this blade shape, but I don't trust stainless balded fans after having 2 of them crack blades on that Ranchero; this fiberglass bladed one replaced them and was trouble free.

I had to laugh when I read up on the history of Flex-a-lite and these fans: "In 1962, Eddy Davis founded this company with the original “flex fan” concept. He developed the first flexible fan out of hand-cut fiberglass roofing material. The concept was to create a lightweight fan that would flatten out at high engine rpm."

The photos are of the old Flex-a-lite, and the Mopar 7 bladed one.

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I really have to tell you that I'm INCREDULOUS that flex fan outperforms the old Mopar. Any chance the belt might have been slipping?

Normally, I would have asked "are you sure" it's mounted the right direction, but I could tell that from the bolt / washer marks on the front.
 
It is not what I was expecting either Del. If the belt was slipping, we never heard it. I have had some TopCog belts slip without noise but this is not one of those. BTW, both fans are 17" outer diameter.

I will say that I ran this fan on my Ranchero 351C for years with the original stock 302 radiator & shroud, 10.2:1 SCR, and NEVER had a lick of cooling issues, even flat towing a 2500 lb rally car and spares in the Appalachians in 90 degree summer weather across north PA on I-80, or through WV. And I mean it NEVER got hot. But that rad was very wide compared to A-body rads so that might have been a factor.

I am thinking they just got it right on this one. We'll keep an eye on the temps and report back if we see anything different.
 
And just to update, the temps are still down 5-10 degrees, and the engine temp stays steady idling at a light. Before it might creep up a bit. This is in 80 F temps.

BTW, this fan is 1" from the rad. The main plane of the stock fan was at 1.5" from the radiator. So that may be a factor.

Bottom line seems to be that you don't know 'til you try.
 
I think you should take that radiator shroud of and send it to me, before that flex fan grenades and rips it to shreds ;)
 
Back in the mid 70s I ran one of those fiberglass fans on my Roadrunner and had good luck with it. Ever since I heard about the potential risk of them coming apart I didn't consider using one again. - And I haven't seen one being used in the past 30 years. I wouldn't mind having one if I was building a 70s tribute hotrod.
 
I had to run one of those on my 440 magnum Roadrunner because before I put it on I pulled the damn pump shaft right out of it's housing and bearings and two weekends in a row I had to put another fan, shroud, radiator and water pump on it.
No problems after that and it cooled fine.
 
^^^ That is great LOL! Never saw that one on the shelf back in the day!
 
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1967 'cuda said:
Back in the mid 70s I ran one of those fiberglass fans on my Roadrunner and had good luck with it. Ever since I heard about the potential risk of them coming apart I didn't consider using one again. - And I haven't seen one being used in the past 30 years. I wouldn't mind having one if I was building a 70s tribute hotrod.
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I never heard of these particular ones coming apart.... the stainless bladed ones are what I fear. I had 2 of those bakc in the 70's before putting this fiberglass one on the old Ranchero, and both SS bladed fans developed cracks near the roots of the blades; I luckily caught them in time. But your point is well made: we'll inspect this regularly.
 
diymirage said:
I think you should take that radiator shroud off and send it to me, before that flex fan grenades and rips it to shreds ;)
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LOL it's yours once it gets shredded!

BTW, this is a /6 shroud; PN is 2998324. Anyone can have one....
 
TrailBeast said:
I had to run one of those on my 440 magnum Roadrunner because before I put it on I pulled the damn pump shaft right out of it's housing and bearings and two weekends in a row I had to put another fan, shroud, radiator and water pump on it.
No problems after that and it cooled fine.
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Dang, what were you running that pulled shafts out? A stock fan combine with high RPM's?
 
nm9stheham said:
Dang, what were you running that pulled shafts out? A stock fan combine with high RPM's?
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Yea, right at 6,200 both times.
I thought it was a fluke so I did it again the next weekend.
Nope, not a fluke :( but fortunately parts were a lot cheaper back then and one of my friend's family owned a wrecking yard.:D
Didn't cost me anything but the down time both times.
 
nm9stheham said:
I never heard of these particular ones coming apart.... the stainless bladed ones are what I fear. I had 2 of those bakc in the 70's before putting this fiberglass one on the old Ranchero, and both SS bladed fans developed cracks near the roots of the blades; I luckily caught them in time. But your point is well made: we'll inspect this regularly.
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Back then a lot of guys were tearing the motor mount rubbers from motors with too much torque & slamming gears. When the engine would twist the fans sometimes would hit the shrouds. Factory fans might chip up those shrouds but the fiberglass ones tended to disintegrate.
 
^^^ Aah OK. I used to have mount motion problems in an Opel rally car.... a few cables fixed that.
 
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