best fan option out there?

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diymirage

diymirage

HP@idle > hondaHP@redline
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I have a 71 duster with a 408 in it, and I want to make sure it stays cool
right now I have the rubberblade flex fan on there

what is the best option out there?
and if there an affordable option that is good as well ?
(maybe from a mid 80s or so V8 mopar)
 
The Mopar Performance clutch fan.
 
thanks guys

ill see if I can hunt one down

(on a side note, none of these got dropping in cars at the line?)
 
diymirage said:
I have a 71 duster with a 408 in it, and I want to make sure it stays cool
right now I have the rubberblade flex fan on there

what is the best option out there?
and if there an affordable option that is good as well ?
(maybe from a mid 80s or so V8 mopar)
Click to expand...

The best option is a direct drive 7-blade OEM all-steel fan with a shroud and a fully functioning seal between the hood and the core-support, and 100% water in the rad,with an additive pkg to keep the waterpump seal happy.Add a hi-flo water pump, and a hi-flo thermostat, and your engine will be nearly impossible to overheat.Get the timing into it as soon as you can(don't panic).
After the engine has run several thousand miles, and you have got the timing and fueling figured out, you can experiment with clutches and fan sizes and things. This way you won't destroy your engine while getting the tune right.
In Michigan, I guess you will need antifreeze sooner or later;So don't forget that as the thermometer starts to fall!
 
if your cooling system is challenged be aware that clutch fans only operate at about 85% crank speed at lo rpm, and idle or lo speeds with little air flow is where most have cooling
problems.I agree with AJ...solid 7 blade fan about an inch from your rad
 
ir3333 said:
if your cooling system is challenged be aware that clutch fans only operate at about 85% crank speed at lo rpm, and idle or lo speeds with little air flow is where most have cooling
problems.I agree with AJ...solid 7 blade fan about an inch from your rad
Click to expand...

anyone know how thick (tall), the clutch is , by itself ??
 
I JUST wrote up a thread on my changeover to a clutch fan setup using a factory 7 blade fan for Darts, etc.
Parts # included for clutch, fan blade and shroud and sources to find them, along with how I modified a factory shroud to fit my aluminum radiator.
It works awesome and my car is now running 25-30 degrees cooler.

Here's the link:

http://www.forabodiesonly.com/mopar/showthread.php?t=346829
 
ir3333 said:
if your cooling system is challenged be aware that clutch fans only operate at about 85% crank speed at lo rpm, and idle or lo speeds with little air flow is where most have cooling
problems.I agree with AJ...solid 7 blade fan about an inch from your rad
Click to expand...


thanks for the advice guys

for the record, the cooling system should be well up to the task, new radiator, new waterpump, clean build
 
With a good fan clutch that works as it should, if the temp is creeping up even at idle, then the clutch should lock up and run at full speed with the rpm.

They only run less than 100% when everything is cold,(below 170 degrees at the radiator) from what I read on the Hayden site.
 
thanks, ill look into what is laying around the local junkyard

(I did read your post, pretty informative, thanks)
 
MobileCustoms said:
With a good fan clutch that works as it should, if the temp is creeping up even at idle, then the clutch should lock up and run at full speed with the rpm.

They only run less than 100% when everything is cold,(below 170 degrees at the radiator) from what I read on the Hayden site.
Click to expand...

In my opinion you now have the best system as far as cooling goes. (I saw your post also)

Radiator
Shroud
Clutched fan

Hard to beat that.

One thing to note is there is different clutch "viscousness's" :D
Some come in sooner than others.

I made the mistake of getting the highest rated HD clutch for the fan on my motorhome and that thing only ever slowed down ONCE and that was in a hail storm up on the Mogollon Rim in AZ.
It was a noisy screaming pain in the backside most of the time, but at the time was worth it for the cooling in the summers out camping in the desert. (slow driving on long dirt roads in the summer when it was 110 degrees out.)
 
Just got off the phone with a local yunkyard... $20.00 for a clutch WITH the fan

I'll be heading out friday...what do I look for, and how do I test it?
 
diymirage said:
Just got off the phone with a local yunkyard... $20.00 for a clutch WITH the fan

I'll be heading out Friday...what do I look for, and how do I test it?
Click to expand...

That's a great deal. I myself would probably opt to get the new clutch, just to avoid the possibility of a bad/worn clutch. I got mine (Hayden 2765) for like $41.00 I think.

Not really sure how to test one on the fly. Should spin when it's cold though and lock up more when the front spring coil on it gets hotter.
 
MobileCustoms said:
That's a great deal. I myself would probably opt to get the new clutch, just to avoid the possibility of a bad/worn clutch. I got mine (Hayden 2765) for like $41.00 I think.

Not really sure how to test one on the fly. Should spin when it's cold though and lock up more when the front spring coil on it gets hotter.
Click to expand...

With some resistance. If you spin it and it doesn't stop itself, the clutch is bad.
 
The assertion that the seven or eight blade fans move more air than the 5 blade asymmetrical is not correct. That's why Mopar Performance offered the 5 blade. The staggered blade design proved to move more air. It's in the Mopar Performance engine book if you want to read.

This is the same reason alternators sometimes have a cooling fan with different size and different spaced blades. They move more air.
 
RustyRatRod said:
The assertion that the seven or eight blade fans move more air than the 5 blade asymmetrical is not correct. That's why Mopar Performance offered the 5 blade. The staggered blade design proved to move more air. It's in the Mopar Performance engine book if you want to read.

This is the same reason alternators sometimes have a cooling fan with different size and different spaced blades. They move more air.
Click to expand...

That's good info to know.
 
MobileCustoms said:
With a good fan clutch that works as it should, if the temp is creeping up even at idle, then the clutch should lock up and run at full speed with the rpm.

They only run less than 100% when everything is cold,(below 170 degrees at the radiator) from what I read on the Hayden site.
Click to expand...

i think that would be the case with the thermostatic unit.
a regular clutch fan is just a viscous coupling that slips saving power..but
maybe i have that wrong?
 
ir3333 said:
i think that would be the case with the thermostatic unit.
a regular clutch fan is just a viscous coupling that slips saving power..but
maybe i have that wrong?
Click to expand...

It does slip when not needed, when it is needed, it locks up and spins with engine RPM.
 
MobileCustoms said:
With a good fan clutch that works as it should, if the temp is creeping up even at idle, then the clutch should lock up and run at full speed with the rpm.

They only run less than 100% when everything is cold,(below 170 degrees at the radiator) from what I read on the Hayden site.
Click to expand...

i think you are correct for the thermostatic clutch fan.
The standard model is just a viscous coupling that slips ..but i could be wrong.
 
I guess I am referring specifically to the Hayden clutch that I purchased, which is indeed a therma-whatever clutch.

:glasses7:
 
Most thermostatic clutch fans never go to complete lockup at low speed as the engine gets hot. The MP fan does. It is a specifically designed high performance piece. That's why it was included in the MP lineup. It is not "just" a Diplomat cop car fan.
 
Ok guys, there are two main types of fan clutch.
One uses a bi mental spring on the front to sense the air temp going by and adjust the hydraulic action (kind of like an adjustable torque converter) and the other is an internal heat sensitive valving system. (still may be bi metal activated but I don't know exactly how those are built.)

The one and only way to test one without driving it is that it has some resistance when you try to turn it by hand (some resistance, not much)
Now if you take that same clutch and twist it back and forth real fast a few times the resistance get less and less because it's cold and therefore is not needed for cooling so they start releasing.
This gives that power to the engine since the fan does not need to be driven at that point in the temps.

Now, when it senses hotter and hotter air flowing around it the valving system (bi metal or other) closes down the slip and drives the fan somewhat of an amount closer to engine RPM's but never a direct one to one, because the clutch always has some slip.
At this point is where you hear the fan kick it at higher RPM's.

A correctly working fan clutch will also a lot of times kick out at higher RPM's unless the engine is really getting hot so it does not take away from the top end power of the engine.

If you turn a sitting cold one it will have some fair resistance, but will turn fairly easy.
If you have one that does not turn at all then it's bearings are frozen up and it's bad.
If you ever run across one that just free spins when the car isn't running, it has lost it's oil or otherwise has a broken mechanism internally and is also bad.

There. :D

Didn't know anyone ever made one that ran 1 to 1 with the motor. Huh
 
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