[Sirrotica]

Old radiator guy showed me how to test to see if the fan is pulling enough air at idle. He held a cigarette in front of the grille to test air flow at idle, it sure gives you a visual cue as to fan and shroud efficiency.

Same guy also showed me how to test the thermostatic clutch at idle. He took some corrugated cardboard and rolled it into a tube and tried to stop the fan blade with it hot, and idling. If you can stop the fan with the rolled up cardboard, the clutch is deficient.

Of course you need to be careful when doing this, and keep your hands out of the fan.........

[68WarDog]

Originally Posted by Sirrotica

Old radiator guy showed me how to test to see if the fan is pulling enough air at idle. He held a cigarette in front of the grille to test air flow at idle, it sure gives you a visual cue as to fan and shroud efficiency.

Same guy also showed me how to test the thermostatic clutch at idle. He took some corrugated cardboard and rolled it into a tube and tried to stop the fan blade with it hot, and idling. If you can stop the fan with the rolled up cardboard, the clutch is deficient.

Of course you need to be careful when doing this, and keep your hands out of the fan.........

What would happen if David completely disengage the coil spring ( completely remove it out of the slot).?I'm thinking it would permanently engage the fan, and may resolve his creep heat ?

[64speed]

Gotta put the wires in a loom but this is pretty much where we are with the engine. I am not very good at aesthetics but everything works as god intended.

[Sirrotica]

Originally Posted by 68WarDog

What would happen if David completely disengage the coil spring ( completely remove it out of the slot).?I'm thinking it would permanently engage the fan, and may resolve his creep heat ?

It would likely free wheel all the time, the modification to have it come on at a lower temp is to wind the spring tighter. Removing it would work just the reverse, no tension opens the valve all the way, is my understanding.

You Tube link for viscous fan clutch:

https://www.youtube.com/watch?v=UwM4OqsLek4

[grivera]

Originally Posted by Sirrotica

It would likely free wheel all the time, the modification to have it come on at a lower temp is to wind the spring tighter. Removing it would work just the reverse, no tension opens the valve all the way, is my understanding.

You Tube link for viscous fan clutch:

https://www.youtube.com/watch?v=UwM4OqsLek4

MGRBLIK posted about this in the below thread - he added a slot to move the end of the the bi-metal spring CCW thereby re-clocking the valve to engage sooner but did not wind the spring tighter.

https://forums.maxperformanceinc.com...9&postcount=31

https://forums.maxperformanceinc.com...ghlight=hayden

[64speed]

I guess I am gonna have to turn the timing back for sure and maybe get a mechanical fan because it got to 220 idling in the driveway after about 15 minutes. It’s a very slow creep but it still creeps

[Sirrotica]

Originally Posted by grivera

MGRBLIK posted about this in the below thread - he added a slot to move the end of the the bi-metal spring CCW thereby re-clocking the valve to engage sooner but did not wind the spring tighter.

https://forums.maxperformanceinc.com...9&postcount=31

https://forums.maxperformanceinc.com...ghlight=hayden

So, will removing the spring lock it up? I've actually never played with the spring on a fan clutch to have hands on experience. But if that locked them in the on position, seems like someone would have stated removing the spring will fix all your cooling problems?

I'm thinking the valving needs to be controlled by the thermal spring, because acceleration and deceleration is going to open and close the valve uncontrolled.

I have seen someone weld the center shaft solid to the fan on a stock car, that didn't work out well...... Having the fan locked isn't going to work out well for many reasons.

[grivera]

Originally Posted by Sirrotica

So, will removing the spring lock it up? I've actually never played with the spring on a fan clutch to have hands on experience. But if that locked them in the on position, seems like someone would have stated removing the spring will fix all your cooling problems?

I'm thinking the valving needs to be controlled by the thermal spring, because acceleration and deceleration is going to open and close the valve uncontrolled.

I have seen someone weld the center shaft solid to the fan on a stock car, that didn't work out well...... Having the fan locked isn't going to work out well for many reasons.

Here is what he said about taking the tang out of the slot and letting it rest unanchored:

"I was able to do some bench testing with a hair dryer and can report some findings on the 2747 clutch at least. First, I am convinced after my testing that just laying the tang of the bi-metalic spring against the stop is a bad idea and either the clutch will be in a clutched-up condition almost all the time or at least be inconsistent. As the spring heats up the end of the tang moves counterclockwise and the valve is free to basically do whatever it wants. It can wiggle all the way from fully open to closed at will when hot with the spring not restrained. Bad idea, and the Chevy article is incorrect in saying that's a good idea."