My old flex fan started pinging at idle ,so i inspected it to find that it had three cracked blades on it ,kinda scared me cuz i spin it to over 6000 often .I bought a new one today that i hope is better and safer .It has a sticker on it that reads high rpm flex fan 8000 rpm.Is this a bunch of hipe or is it better than the others ?I noticed the rivets , the ,body ,and the blades are alot thicker than the old one.I dont want to hurt anyone or myself if i can get a better one somewhere .It costs me $45.00 bucks if that counts for anything...
8000 fan rpm,which may be faster or slower than the engine depending on the water pump and crank pulley sizes.I use one of those newer flex fans with the paddle type blades.Bought it a few years ago,said 8000 rpm max.
Flex fans can make a mess of a hood real quick - one solution is to remove the hood. There may be other solutions as well.
My fancy flex fan let loose at less than 6000RPM, the blades had more fun than a tornado in a trailer park. It cut the rad hoses, fuel line, tranny fluid lines, vacuum lines, plug wires, fan shroud.....and tore a big hole in my radiator. It made a sickening sound. My buddies that were within earshot thought for sure I grenaded my fancy big block. (so did I...) I don't much care for flex fans....
i dont like em ive seen holes in hoods and fenders from em, when i was younger i put two fan extensions together to get the fan closer to the radiator on my 66 chevy school bus, well after i got the exaust done i reveed the 454 in first and when i hit second the water pumps shaft broke destroying a radiator, both radiator hoses and dented a inner fender, your shoulda seen the fan though, after i picked up the fan i thought wow that was a stupid corner to cut, i built a bitchen fan shroud after a radiator recore.
Flex fans suck. Period. Get a thicker steel fan...speedway has them, summit has them, etc. They will work better with a far less chance of killing you. At a Kwik Kar I worked at a few years ago (happened before I'd started working there) the manager and asst. manager were working on the managers mullet mobile after work one night. They'd just finished putting a big block in it with some redneck engineering. The asst. was checking the timing with a light under the hood, the other guy was in the car working the throttle.....flex fan came apart and went through the asst. managers chest and face.....he's one ugly sumbitch now.
Lose the flex fan. I spun my small block showing off for my friends like a dumbass about 15 years ago. KABOOOOOOOM!!!! Luckily the only damage was done to the frame. The frickin blade stuck in it like the sword in the stone......and I pooped a little.
HAHAHAHAHA!!! I thought I was the only one that said that. Yhanx for the laugh. P.S. I hate flex fan too. I've had two come apart on me, the first one was pretty old and I should have shit canned it a month before it came apart. The second was like two months old and it let loose and punched a hoe in my hood. Get a clutch fan.
i had one come off as well, it was on a pulling truck with a 400 sbc, brand new fan with a long spacer, looked to be running true as could be, decided to check the max. advance on the timing, my buddy held the throttle at 4500 while i put the timing light on it, closed the hood and my buddy gave it another shoot on the throttle, fan came off and chewed the crap out of the inner fender right where my face was 30 seconds before that.
I've had the metal blade flex fans come apart as well as the glass ones. Not quite as exciting but they tend to loose blades after a while.
As far as damage to the hood ,i would rather do that and contain the loose blade than hurt someone,but i doubt at 6500 rpm that the hood would stop much . I have also heard of the other types coming apart as well (glass and steel).I wander how many of these that came apart in the stories were already cracked before they flew apart?I inpect mine often for cracks,but i know it can prolycome apart without warning as well.I guess the only foolproof deal is to take it off completly and get an electric unit ,but i hate the way an electric looks on a hotrod (especially a gasser) ,and when your in Dallas traffic and the electric goes out you are screwed.Thanks for all the info and help guys .I think i am gunna try and make a real strong shroud and get a steel one...
Get one of these.... 15" http://store.summitracing.com/partd...LX%2D1615P&N=700+-128484+115&autoview=sku 17" http://store.summitracing.com/partd...part=FLX-1617P&N=700+-128484+115&autoview=sku 18" http://store.summitracing.com/partd...part=FLX-1618P&N=700+-128484+115&autoview=sku and the point of the shroud is to help the suction of air through the radiator, not to stop an exploding fan blade. Unless you make it out of 10 gauge steel (or thicker), it's probably not going to help that.
I'd second the suggestion to get a clutch-type fan. The clutch will only let the fan spin to a certain rpm and then it "slips" due to air drag on the blades. Less horsepower used to move excess air. I'd go electric for the track for that reason, but I'm not married to the idea of having everything be 100% era-correct on a car.
watch out for the ford fans. I know back in the 80's they had a recall on the fans because they were coming apart even at idle. There were some people hurt and even killed by them. Boy I just dated myself on that one. I have not ran a flex fan after that recall.
Old ass thread, but still relevant. This statement is totally incorrect. The clutch in a factory type clutch fan is controlled by one thing and one thing only: thermonics (heat). It doesn't matter how fast you go. If your motor is hot and you have a clutch fan, the clutch fan is going to lock up and spin that fan no matter how many RPMs you're turning. Now, there are viscous speed coupler clutch type fans, but they are race only items, not factory...and these are useless on the highway. Try towing with one of these...or even just make a run up a steep grade. High RPM...load on the motor. Maybe you even have AC and you have that cranked too. No fan running because your viscous RPM race clutch has your fan disengaged... I've run a number of flex fans over the decades. I have never once had a flex fan come apart on me. I've never been sliced up by a flex fan as others claim they have. Use a large paddle blade model of quality design. If you use a cheap product, you can expect commensurate results. If you race, I would not use a flex fan. If you spend any time at all on cruise night and your car is a street car, paddle blade flex fans are a great option. They move prodigious volumes of air, especially when used in conjunction with a good shroud. I had a mechanical (solid steel) fan throw a blade on me more than once.
It's a good idea to not be in line with the fan when the engine is revved up and the hood open, especially when working on the car.
I had an old Dodge 4x4 that I used as a tow vehicle. One day the motor developed a shake on start up, the morning after a late night haul. When I shut it off I noticed the fan had stopped where I could clearly see it was was a fresh break for a missing blade. The blade was no where to be found, apparently it came off during the haul the night before! It had to have vacated through the bottom as there was no dents in the hood, and I had no idea it had come off. When it broke off and came out, it missed everything! The entire rad shroud was undamaged, all the belts were accounted for, and the trans cooler lines were OK, nothing was damaged except the fan. I replaced that flex fan with a solid steel 7 blade fan. I haven't used a flex fan since. Gene
I don't much care for flex fans, and I have one as a wall hanger where it can't hurt anyone or anything.
It's the aluminum blade flex fans that fail (and have given flex fans a bad name)...and from a metallurgical standpoint, that makes perfect sense. Aluminum is not a metal that is known for its durability when it comes to it's elasticity. I have two cars that are equipped with quality large blade, stainless flex fans. One has been in operation thru two motors and 200,000 miles. This fan replaced a rigid steel fan and clutch that threw a blade long ago. Only reason the blade didn't pass completely thru the hood is because it hit an underhood cross member. Still dented the hood skin. Again...people shouldn't go cheap here. You get what you pay for.
From what ive heard the early Flex a Lite flex fans had issues because of weak blade mounts. I cant speak from personal experience on these though. I use these and they're a solid product. I sometimes spend hours on the cruise at events like Hot August Nights. They keep even cammed up, ported engines cool at idle. https://shop.advanceautoparts.com/p/imperial-high-flow-flex-fan-221615/6014925-p
Sorry fellas...... But I'd rather stick with a 7 blade clutch fan.... I've seen what the flex fans can do when they explode....
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