salty_waders

I have a fan clutch on my '65 327/350 that I bought at NAPA. It works fine but I noticed that the shaft is shorter than the factory original. The longer shaft on the original allows the fan to be closer to the radiator, which helps cooling. Does anyone know if the fan clutches sold from Ecklers etc have this longer shaft? Does anyone know where to get the "correct" one? Thanks!

rustylugnuts

Did you ask Napa if they list two different length shafts? You might be able to make an exchange.

Just a suggestion.

rustylugnuts

Nowhere Man

you can still buy a service replacement from GM. it looks close to old one, and works like originals

MiguelsC2

Only exception is the temp the fan enages is in the 200-210F range instead 180-190 engangment. There is a string here that explains how to correct that. Maybe someone has the link?

Nowhere Man

he have that in both of dads 67 SB and the temp rarely gets over 190*

MiguelsC2

Guess that part depends on where you live. Down here in the steamy south. The difference in the clutch temp engagement is noticable.

62Jeff

http://forums.corvetteforum.com/1571472351-post7.html

R6T7

Has anyone tested this "fix"? I saw the post some time ago, but I haven't heard any reports on how it worked.

Bob

Bob's 64

Did this fix to my 64 300hp. Worked great! Lowered the temp
between 10 and 15 degrees.
Bob

65 vette dude

Also lowered mine 10-15 degrees

salty_waders

You mean from a dealer?

salty_waders

From a GM dealer? Online? thanks...

Powershift

Paragon should have them. Part number 714. Cost $125 in my 2006 book. Also available from GM Parts Direct. I don't have the GM long number handy, but it should be in the archives.....it's been discussed frequently. (Edit: Should be #3916141. Cost $160.)

Also "the partsladi" sells on-line. Just "goggle" the name or visit her Ebay Store. There has been some recent discussion regarding the fan clutches from her. Not everyone has been happy. She sells the GM boxed one for $175 and also an Eaton one that is supposed to be the same, but in a non-GM box and less $$....shown at $90. I don't know for certain that they are the same. So if you buy from her, I would recommend getting the GM boxed version that is more expensive. Others may have different opinions/thoughts.

Also call Paragon and see if their clutch fan has the GM number and their latest cost. Then make you decision.

Larry

JohnZ

The distance from the fan to the radiator isn't important - what matters is that the fan blades are located half-in and half-out of the rear edge of the shroud; that's what makes the fan efficient. The GM #3916141 is the one you want - I have one on my '67, works fine.

R6T7

Hi John -

Your post caused me to belive that I may not have the right fan on my car - my fan is a PN 3931002 - it is a 7 blade fan with curved tips. Is this the right one for a '67 300HP, factory A/C, powerglide car?

Thanks,

Bob

Powershift

Bob:

All 1967 Corvettes had 5 blade fans....no exceptions. However, my 1967 factory AC 327/350 HP car also has a 7 blade replacement fan, which works very well in the Louisiana heat.

The part number for the 1967 small block with AC fan is #3789562 or #3863137 (opt).

Larry

EDIT: I would not recommend changing your 7 blade fan for the 5 blade original one. Suggest you keep what you have.....I think it cools better. Plus original 5 blade fans are $$$$$.

R6T7

Larry -

Thanks for the feedback - I would agree that it seems like the 7 blade fan should move more air than a 5 blade, but I'm not sure about that. My car runs cool in almost any combintation of driving and temperature - even when it's 110 degrees here, I can drive it with the A/C off (not that I want to) in city traffic, and the temp never exceeds the 180 mark. But with the A/C on, it will go well past the 210 mark in city driving, to the point where it will start to puke coolant. However on the highway, even in 110 degree heat, and the A/C on maximum, the engine will not overheat - it will stay right around 180, which it should as I'm running a 180 thermostat.

So I'm pretty sure the issue is either the fan clutch, or the fan itself, so I'm going to try the adjustment on the fan clutch, and see if that helps. I'd really like to know if a 7 blade fan moves more air than a 5 blade fan, however - maybe it has more to do with the blade spacing and pitch?

Bob

Powershift

Bob:

Does your car have the K19 Air Injector Reactor California emissions package? If it does, the retarded ignition timing may be part of your issue.

Regardless, I would carefully check your initial, centrifugal, and vacuum advance vs. factory specs. If K19 equipped, I would consider revising the distributor ignition map.

Also, the lower idle RPM (500-550 RPM in drive) with powerglide does not help your cooling/air flow.

Larry

salty_waders

JohnZ, your right, what I meant was that if the fan was closer to the radiator then the blades will be 1/2 in 1/2 out. I was at a car show looking at other C2's and noticed the fans on the other cars were about an inch closer inside the shroud. That is when I figured out that the fan clutch Im using has a much shorter shaft or snout on it. I ordered the "correct" GM replacement today. I never thought about this when I bought the $39 fan clutch from NAPA! Its the little things like this that help cool the car.

vark_wso

Bob

3931002 (18", 7 blade) is the SERVICE REPLACEMENT fan for midyear with air conditioning.