fan clutch

[shotgun]

Was that with a thermal clutch or just mechanical.

From Hayden, "Non-Thermal Fan Clutch
Low cost alternative for some standard thermal clutches.
Always engaged, less fuel savings than a thermal clutch.
Spins at about 30-60% of the water pump speed.
Shorter life expectancy.
Cannot replace a heavy-duty clutch.
Identified by the smooth, steel faceplate, (without a thermal spring assembly), on the front.


Thermal Fan Clutch
Varies the fan speed with temperature of the air behind the radiator.
Engaged (high speed) operation provides maximum cooling.
Disengaged (low speed) operation provides fuel savings and noise reduction.
Greater life expectancy than a non-thermal clutch.
Briefly engaged at cold start-up.
Engages at about 170° radiator air temperature, (about 30° lower than coolant temperature).
The air temperature coming through the radiator is sensed by the bi-metal thermal spring on the front of the thermal fan clutch. It expands and contracts with the change in air temperature operating a valve inside of the clutch. When cold, the silicone drive fluid is pumped from the working area to the reservoir. When hot, the valve opens allowing fluid from the reservoir to be transferred to the working area thereby increasing the fan speed. The clutch disengages as the air temperature decreases, closing the valve and allowing the silicone fluid to be pumped back into the reservoir.

A thermal fan clutch is engaged on a cold startup because the fluid drains into the working area when the engine is shut off. The fan clutch will slow down shortly after startup as a result of a pumping action produced by a difference in speed between the shaft and the body of the clutch."



2 tenths is alot of h.p., so I am guessing it was siezed and spinning at engine rpm.

When it declutches only the staff is spinning by engine power.

It may still spin due to air flowing over the blades.

 

[creepin cutty]

it looks nicer 8)

 

[85montess]

I have a/c but its not hooked up. I haven't decided whether or not i wanted it. It is a borderline street car, but its also my daily. I went with a HD Thermal fan clutch. Now she sits around 200 degrees, which in my opinion is a bit hot......or is that normal for these kinds of cars? I have a low temp thermostat (180) and an aluminum radiator (which is bigger than stock). The rest of my setup is in my sig but I'm just curious of your guys' opinions?

 

[R/T kota]

Stock fan and I assume it was a thermal clutch.
Truck was only one year old at the time and the fan was not seized. Truck has a back up electric on it from the factory so no real need for the clutch fan. Been running like that for about 5 years now.

The fan is heavy. If you have any kind of a clutch fan on your car, start it up and watch the fan when it free wheels. It does still spin. Even when you rev it up. Not as fast as the engine but it does catch up. Still makes drag.
I have a box full of about 150 time slips on this truck.
When I track tested it, I made 2 or 3 passes with it on and then removed it and ran about 4 or 5 passes with it off. Went from a 15.44 (best with on that night) to a 15.21 (best with off)
It also shifted harder going into second gear.

I have manged to knock a full second off the et of this truck and only spent about 30 bucks on it.
Best time to date is 14.96 at 93 mph
Not bad for a 4500 lb pig with a rated 255 hp.

 

[dan2286]

One more thing you have to think about is that an electric fan can put alot of strain on the alternator. In some cases it will not affect anything, but if your alternator cant handle the extra amperage you will be going through them alot.

 

[megaladon6]

however it is easy enough to upgrade the alternator. and since most people are running a lot more stereo power than stock (and if you have EFI or a few other things) it should be done anyway.

 

[shotgun]

R/T kota, that is an impressive gain from a fan delete. I am swagging about 25 flywheel horse or 10% of your 255 rating.
Yours must be the exception to the rule, there is always one.
Good job.

Here is my recipe for street driven cars. I specialize in Pontiacs which are not known for running cool.

Stock type 4 core or aftermarket aluminum ( usuallly customers request)
7 blade, deep pitch a/c fan attached to HD Hayden clutch
Full shroud with foam tape to "seal" it to the radiator
180 stat with couple 1/4" holes drilled in it
chin spoiler
1/3 Dexcool, 2/3 deionized water(not deminerlaized)
sometimes Kool-it or water wetter

I have some 12 second 4000# cars that have a/c using this with no problems.

Also my 83 wagon with a "warmed" up 350,5 speed, 3.73 , also an a/c car, runs at 160-180 with all stock cooling with the exception of a hd clutch and Camaro radiator( reaily thin aluminum unit).

I think if you have everything working fine,your spoiler and cooling box are intact right?,it may be time to look elsewhere.

Timing, lean carb etc etc.

 

[85montess]

I think if you have everything working fine,your spoiler and cooling box are intact right?,it may be time to look elsewhere.

Timing, lean carb etc etc.

I think you may be correct, because there is now way my brand new radiator could be shot. there is also a brand new hd fan clutch and 180 thermostat could be malfunctioning. So there may be some truth to timing, mixture, and what not.[/quote]

 

[R/T kota]

R/T kota, that is an impressive gain from a fan delete. I am swagging about 25 flywheel horse or 10% of your 255 rating.
Yours must be the exception to the rule, there is always one.
Good job.

Thanks.
It was a very heavy fan. Not all cars would benefit as much as I did as most clutch fans I have handled in the past were lighter. Point was they do make some drag on the engine.
That is why you see some go to lighter pulleys. May not seem like much but it does make a difference.

Back to G bodies and with out going back to read the original post, one thing I have noticed over the years is when doing an engine swap from a 6 to an 8, the one piece that seems to be over looked a lot is the air deflector/spoiler below the rad support.
A lot of the 6 cylinder cars had a shorter deflector and after swapping in a v8, the shorter deflector stays on the car. This does not always supply enough air to the rad.

Also going too cold of a t stat is not always the right way to go.
My 406 I ran in my camaro worked better in traffic with a 190 over the 180. The 180 would open up and then never close again so the coolant would not stay in the rad long enough to cool.
Going to the 190 allowed the t stat to close to let the coolant cool before opening again.
Not the case in every car but something to look at.