That makes sense, and matches what I've seen, but it also leaves me scratching my head over the utter failure of the combo you like (standard-duty clutch w/5-blade fan) to pull enough air across the condenser to make the A/C work worth a toss in my '89 D100. Can't say I'm entirely happy with the XHD 7-blade fan with XHD clutch, but I'm happiER. An electric fan would be much better; I'm just not entirely sure I want to spend the money.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

That is interesting, and odd. I've noticed that some of the newest vehicles have very high-tech looking fans. usually LOTS of blades, but each blade is very short and mounted on a large-diameter hub.

And the latest clutches seem to work much better also- when they're off they REALLY freewheel, and when they're on they're REALLY tight. I did find one in a junkyard once that was setup for non-serpentine belts (all the modern ones are reverse rotation) but I'm not sure what the application was- I *think* its a ~1977 Ram with a 440 and HD cooling- just not positive. The problem with these is that if the engine is cool, just the A/C condensor heat won't be enough to kick them in. I really like the setup in the 2000 Durango my folks own- a regular engine driven fan, plus a small electric fan that kicks on with the A/C. I replicated that setup on my '66 Polara, and it works quite well.

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That is exactly the setup I have in my '89 right now ('76 Ramcharger 440 w/HDC, same fan and clutch also used on many other big block Mopars starting around '70). And yes, I've noticed that the A/C condenser heat isn't enough to engage the clutch, though the semi-freewheel mode seems to pull adequate air across the condenser so far.
Why go that route rather than pure electric?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

A good question, really! All-electric with the fans available now makes a LOT of sense. The biggest drawback is the current draw at idle. The finned-case Mopar alternators genrally aren't up to that task, but my Polara now has a 100A alternator so it could easily go all-electric. Removing the fan's gyroscopic and vibrational loading from the water pump bearings HAS to be a good thing also.

But the standard-duty belt driven fan plus a small auxiliary electric has its merits as well- you're not screwed if the fan fuse blows and you don't have a spare, you're not screwed if the fan motor fails, its quieter than all-electric.

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Just adding my two cents...

My '66 has a cheap aftermarket flex fan and no shroud. I've been meaning to put in a stock fan. The flex fan I have sucks, er, well, actually, it doesn't suck enough air through the radiator. I've had my Dart overheat before while idling in a line after a long highway trip. My plans for my turbo project include using an electric fan.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Electric is definitely the way to go.
I put one on FURTHER ('64 Valiant) and noticed a difference right away.
Quieter, and accelerates quicker. I think my gas milage even went up a bit.
The fan I used has reversible mounting feet and blade, so it can be mounted to pull or push. I put it in front of the radiator (just under the in neck) and behind the grille.
I used an adjustable thermostat from AutoDrone, and it's been working great!
I especially like having the clearance between the radiator and the water pump pulley.

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aed
/6>V8

The only problem with electric fans is that you really need to upgrade your alternator at the same time with the older cars.

I'm already at a discharge state at idle with the lights on, add an electric fan and I might get into trouble

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Find me a good one that'll work with the nonexistent clearance between rear of radiator and front of engine in a '60-'62 A-body; I'll pay you a finder's fee!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Would a stock '64 alternator be OK with an all electric set up IF you had your idle @ 900 rpm ???

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"Nothing in all creation is hidden from God's sight. Everything is uncovered and laid bare before the eyes of Him to whom we must give account."

The only way to find out is set your idle to 900 and test it by adding about an 8 amp load when you have your lights on (2 additional headlights jumper wired should do it)

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

What about a Hayden or Flex-a-lite, mounted as a pusher on the front side of the radiator (or rear side of the A/C condensor).

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I am surprised we have come this far in the discussion and no one has mentioned efficiency.

IMO the best setup to run is a fan clutch, because with an electric fan you lose energy in the conversion of motion (rotation of the engine) to electricity and then back to motion (of the electric fan). With a fan clutch there is no loss of efficiency at all. Every drop of gas required to turn that fan, regardless of whether the fan clutch is slipping (just less drag) is directly converted to airflow across your rad. A thermostatic fan clutch is the best. It does have its drawbacks, cooling air at idle, this can be compensated for in the design of the fan itself.

As an aside, I have always wondered why direct drive fans on the older cars are asymmetrical; anyone know?
Look at a Volkswagen/Audi. Their fans are usually mounted in front of the radiator with the blades pointing the other way. If for some reason they do not work for you, you can adapt a regular electric fan to work in this position by finding a fan with the correct blade angle, and adapting it. Look to heavy equipment. There is even an aftermarket mfr of a reversible pitch fan for sucking/blowing debris out of the rad by reversing the blade pitch! Does this with pneumatics. I have wondered how well this would work on my car in conjunction with a centrifugal switch inline with the speedo cable, make it a blower fan up to a certain speed (say 40MPH) then the switch closes and reverses the blades to a puller fan to zero the drag or even recover a little energy from the air at high speeds.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

But an electric fan doesn't have to run all the time, so there's lots more efficiency when it's not running...................

Now overall with it running and not running it may be a wash efficiency wise.......


As for asymetrical blades, I think it is for noise reduction. There is less likelyhood of some nasty harmonic noise starting....... (the odd number blades with different spacing are another example)

I also noticed this with my parents old nissan that had 2 electric fans, each fan although the same diameter had a different blade count, one was odd, the other even.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

That may become possible once I install a parallel-flow condenser, which is 0.7" thick instead of 1.5" thick...

...but I'm not betting on it.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

True, but theoretical efficiency advantages like this don't always translate to practical efficiency advantages. Look at how much more efficient the hybrid cars are compared to their straight-petrol counterparts, even though the hybrids run an engine to spin a generator to charge batteries to run a motor. Look at diesel-electric locomotives, configured that way (diesel engine runs a generator charges batteries run traction motors) because it's more efficient.
True, but the fan's still turning (and taking energy) when it's not needed, which eats into system efficiency.
Some clutched fans are asymmetrical, too. It is, as already stated, for noise control.
I may do that. Last one of those I looked at was a '90 Jetta, piece of trash I was tasked with keeping running. That one had an electric fan pulling air from the rear.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.