Fast81

Got a flex fan "thrown in" when I bought my 81. Compared with a few on the shelf at the local Autozone, it's the hi RPM design. I'm thinking of putting it on now that my improved motor with headers kicks out a little more heat. Do I just bolt in on in place of the stock fan or do I have to remove the clutch also?? 2nd question: is there any way to check that it hasn't warped while off the car??

Just exploring all my options before diving into an $alum$ $radiator$. Already have the hi-flo H2O pumper

Riceater

You can keep or toss the clutch fan. I would keep the clutch fan in the garage just in case the electric doesn't do it.

As for the striaght part, just take a straight edge to it.

sb69coupe

What problem are you trying to solve? Is the car running hot? There is a very good writeup on how all the elements of the cooling system work at
http://www.dewitts.com/download/Corvette%20cooling.pdf

Fevre

Run both and see if you get a diff in cooling. Flex fans look nice but I have not seen any solid proof they offer any advantage, some tests show the opposite. :eek:

dath

Yeah, they didn't look like they would blow as much air to me either... I actually ended up buying a cheap plastic flex fan as my fan clutch was leaking and I wanted to get her up and running quickly. I may stay with that cheap plastic flex fan as it pushes some serious air. It also doesn't have the same shape, the blades are bent 90 degrees or close to it, amazing how much air it moves around.

I was going to try out an electric setup at some point, but I'm worried I'd need a new alternator as well... Oh joy!

Fast81

It never ran hot until I bolted on alum heads, hi rise intake, underdrive pulleys and headers -- it also never had much performance (stock iron heads, ex manifolds) !! Very soon after road testing the improved engine, it started brushing the bottom of the warning zone on the temp guage in stop-n-go traffic. Since I'm running underdrive pulleys, replaced original H2O pump with hi-flo. Much cooler now, just wanted to get some intel about flex fans since I had one taking up garage space.

76Frankenstein

I am using a Flex-a-lite #1317 Fan w/spacer #14538. It takes the place of the entire fan/clutch assembly. With my Griffin radiator, the temp climbs to 180, t-stat opens, and the needle stays pinned there at all times, cruise or idle, fast or slow. Much more cost effective than electrics, IMHO.

Here are the links to the parts. Be sure to get the corvette 3/4 pilot spacer.

http://www.flex-a-lite.com/auto/flex.htm
http://www.flex-a-lite.com/auto/spacer_kits.htm

If ya need pics of the install, let me know - I tried to take some, but the batteries died in my digital camera :rolleyes:

Viken

I got a flex fan with spacer in my '80. Went with it because it was cheaper than replacing the stock clutch/fan setup. Moves lots of air, but a rather decent mechanic I know, apparently doesn't think too highly of them. He claimed that flex fans bring a slight decrease in hp/mpg. Never ran the car with a working flex, so never had the chance to compare numbers.

dath

I suppose they *COULD* bring the hp/mpg down, but it seems like it would be such a small amount that it wouldn't be easily measureable...

jerryp58

"He claimed that flex fans bring a slight decrease in hp/mpg"

Hmmmm.... I always thought the claim was the exact opposite.

Viken

I dunno. Just his opinion I guess. I agree that the amount would be rather insignificant. Don't have any complaints with mine, either. :D

WhyFly

I lost an engine partially to overheating two years ago. When I replaced the engine I used the stock clutch fan but also installed a single 16" electric in front of the rad and a hi flow 180 degree stat. I wanted to install a light weight flex because I think they look great but was told they were quite noisy and had a tendancy to fly apart at high rpm. Do you folks that run them find them noisy and have you ever heard of one disintegrating at high revs..? I'd still like to put one on.. :steering: :thumbs:

76Frankenstein

I hear very little from my fan, but I have a loud Pete Jackson gear drive which may mask the fan :D
I have never known anyone who had a failure with a flex-a-lite, but then I only knew a few who ran them, maybe others can chime in on that regard.
One tip: Wear long sleeves and gloves when installing. I ignored the warning, and had to pull the fan again to clean the pool of blood off the fan shroud. :eek:

DMONSVETTE

I use flex fans. Also, watch out they are very, very sharp. Normally I don't even know I got cut until I notice the pool of blood. Becareful.
:yesnod: :iagree: :seeya

bigvette1

Yes, they are noiser than a stock fan and clutch, but not obnoxious. Watch it as the other post said they are sharp as hell. I used some emeruy cloth and took off the sharp edge on the blades as I was getting nicked every time I reached in the fan area.

gkull

I got rid of the heavy stock clutch fan 20 years ago. I always used the stainless steel high rpm flex fans. If your into petal to the metal driving you want as little rotating mass as possible. I just recently went all electric fans

Like you I use underdriven crank pulley and larger alternator pulley because my powermaster 100 amp alternator is limited to 17,700 rpm.

Fast81

You guys already running the flex fans - did you keep the clutch or not?? Also, if I just bolt the flex in place of the stock propellor will I need the spacer??

Oh yeah, the noise shouldn't be a issue (if you can hear it over the Accu-drive gear set, my exhaust, my stereo,.............. etc)


[Modified by Fast81, 8:09 PM 8/27/2003]

Fevre

You need the spacer to put it where it needs to be, just inside the shroud. The flex fan eliminates the clutch and prolly won't bolt to it anyways unless you like to fab.

76Frankenstein

You will need to use the spacer - here is pic of mine - apologies for quality, but should give you an idea of how it looks

Chris69

I recently installed the 17" unequally spaced 7 blade heavy duty version. I don't hear it at all when driving, even with the hood up and revving the motor, it's not that obvious. I like it. That, and adding the correct rubber seals around the shroud seems to have eliminated my overheating problems. Seems to just hang around 180. My overheating might have had something to do with the 15" fan that was in there, and installed backwards! :smash:

Oh, as already mentioned, they are sharp! It's got warnings about it, and they are correct. I filed the edges a bit to take the 'razor' out of the 'blades'. Worked great!

You can see a pic here... http://www.c3vettes.com/69_engine_pics.html