Like everyone here I'm sick and Tired of buying Junk that looks like the real thing but doesn't work........I've bought a couple of Fan Clutch units and at Temp (220+) they still spin freely.........the parts stores say this is normal (Imagine that)........Is there a source to buy one a "Real" one that actually works correctly......

Thanks
Ken

Yes,i have installed approx 4-5 new NAPA/MFG BY HADEN hd/ac type fan clutches on bbc's & SBC's in the last yr or so and every one locks up properly in traffic when rad/motor gets hot which happens @ approx 200deg f in most cases i have been involved with.

But dont bother with std duty fan clutch that doesnt cut it in some cases like maybe yours when in traffic . Do yourself a favor like i do and buy the HD/AC type fan clutch that locks up at a little lower temp and also locks up tighter for more fan rpm/increased airflow when motor gets hot in traffic even if you dont have AC,doing that usualy drops idle/traffic temp a bit.

Another thing i can think of it maybe your temp gauge is reading improperly and its not as hot as you think it is and that's why the fan clutch isnt locking up becasue its not really

Also,if running a perf cam make sure your running at least 16-18 deg base timing along with a vac adv hooked to fullintake vaccum all te time which will also lower idle/traffic temps.

So make sure to verify temp gauge accuracey too.

And i agree with you that 220 deg f is too hot for our older gen bbc/sbc motors to be at on a regular basis for any length of time in traffic. The newer gen motors/cars of today designed for better fuel mileage & lower emmission with EFI etc are different story where 220 deg f in traffic is common to see before elec cooling fan/s come on.

Scott

Scott, do you have a part number for the Napa clutch. Hayden says they do NOT offer a heavy duty fan clutch.

Chuck

I have a 70 SS 454 AKA (468).. I am using a 772 fan blade and a Fan Clutch from the local Chevy dealer. The clutch I am using is from a mid to late Eightys --3/4 ton Burb,454, with dual A/Cs. This clutch has square corners and fits inside a 3947772 fan blade. It aint cheep $133.00....
On a very hot day with the A/C on (in TRAFFIC) it will climb to 215 on a Mech. gauge. Shut off the A/C it goes down to 200-205. I can live with this.
Bob

Bob,fyi,i am 99% sure gm used the severe duty fan clutches on the chevy burbs with dual ac which is best cooling of all for sure.

But i dont rec them only because they lock up considerably more then the hd/ac type clutch and people complained about the additonal fan noise, noticable reduction in fuel mileage & perf-power,along with more dirt being sucked into engine compartment too ,but like you said they do cool like heck,that's sure and in some case that could realy help someone out with a tough motor setup to keep coolin traffic.

But the hd/ac type fan clutch i have been rec locks up considerably more then the std duty which is in most cases enough to get the reliefe/enough temp reduction in traffic when people are having heating up issues in traffic only when running a clutch fan if a else like timing,carb fuel calibration,radiator ,fan & shroud are correct .BUT IF I RAN ACCROSS A REAL BEAR TO COOL IN TRAFFIC WITH A STOCK COOLING SYSTEM I WOULD DEFINATELY GIVE A SEVER DUTY CLUTCH A TRY AS LONG AS THE PERSON I WAS DOING THE WORK UNDERSTOOD THERE WOULD BE MORE FAN NOISE ETC ASSOCIATED WITH THE SEVERE DUTY CLUTCH.
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Chuck,here are the hd fan clutch pt#'s that fit gm's 7 blade 772 clutch fans from 69 thru 70 but they also fit gms 7 blade clutch fans for 71-73 with a different pt# fan that i dont remeber of the top of my head.

If your fan isn't the gm 772 fan then go diectly to the hayden site and do some cross ref application looking thru catalog to find a proper fan clutch if they dont list a hd/ac type fan clutch for your car . In that case try to find other car and or trucks that uses the same fan as your setup does and then look for hd and or ac application for the othe vehicles with the same fan as you have that may list the hd/ac fan clutch for them but not your car. Doing this has worked for me many times over the yrs because the database listing havs been corrupted over the yrs and many of them are lacking in accuracy these days.

I worked in the autoparts store industry yrs back so i have some insite into how it works & how to find what you need when they dont list it but you know its stillmfg for other cars with similar setups,you just have to investigate when that happens.

Thats how i found the hd fan clutch for the 772 gm 7 blade clutch fan for my 69 396 thats really common at dirt and was used for many yrs on tons of chevys.. I had to do that because napa didnt list a hd/ac fan clutch for 69-70 chevelle with ac & 772 fan even though they mfg pelnty of those cars in 69 with sbc/bbc with ac being very common.

The napa hd/ac fan clutch for 772 fan cost me approx $65-$70 out the door.

Scott
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napa fan clutch (from napa site)(I BELIEVE HAYDEN MFG'S NAPA FAN CLUTCHES)

tem271303 - h/d

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hayden fan clutch (from hayden site)

2747 h/d
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imperial fan clutches (from hayden site)

215046 h/d