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Discussion Starter #1
hey it's been a while since i've posted. has anyone ever heard of a belt kit for the 4.6L to convert it to a non-serp setup? a few years ago i was working on my brother's subaru legacy, and i noticed it had 2 belts in simple triangle routes. since the 4.6 is a rat maze of rubber, does a kit exist with different pulleys for this? maybe extend half the pulleys out farther and put a double belt wheel on the crank?

oh and also, i need a new 96-97 tbird tail light bar if ayone would sell one.
 

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Discussion Starter #3
well it was nice that even though his ac took a massive dump on him, the belt to the water pump was still good. so at least he could drive it to a mechanic to get that fixed. too bad the nimrod was too broke to get that done. ya, we live in a desert state. no ac really blows in the summer. oh well, it was just a curiosity question.
 

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You'll hear the bearing squeaking for at least a month before it seizes; buy a AC eliminator, and keep it in the car, if you're worried about it. :)

Or, you could fix it when it starts making noise...
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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Although it doesn't do anything if the temperature is under ~50 degrees.
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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The a/c clutch won't cycle if the outside temperature is too low. As the ambient air temperature decreases, the pressure inside the a/c system does as well, and the cycling switch will inhibit the clutch from actuating when the pressure drops below a certain point. This point usually happens when the air temperature is around 50 degrees.

From the FSM:

"The A/C cycling switch:
-senses pressure in the A/C evaporator core pressure to control operation of the A/C compressor.
-uses this method of control to stop operation of the A/C compressor during ambient temperatures below approximately 10*C (50*F) and prevent icing of the A/C evaporator core during normal system operation."
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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I never said the clutch doesn't come on with defrost/floor, defrost and panel/floor. If the system is correctly charged, it won't come on if it's too cold outside. Otherwise the evaporator core would ice over completely. See the wikipedia article related to gas laws.
 

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Start with PV=nrT. Work from there, lol.

It doesn't have to work very hard to dehumidify air, so it only cycles for a sec, unless the system is almost empty.

As long as it gets below the local dewpoint, it will dry the air; that can be 2° in the winter.
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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Then if the clutch is cycling and it's 2 degrees outside, where does all that moisture go? It would have to stick to the evaporator. After a few minutes the evaporator will ice over and no air will flow across it. And because it's so cold, it won't thaw either. Additionally, for R-134a to reach 2 degrees F, the pressure in the evaporator would have to be under 8 PSI. That's well below the cutoff point for the cycling switch in these cars. The switch cuts off at 22-28 PSI, which is between a 25 and 32 degree refrigerant temperature.

http://en.wikipedia.org/wiki/Gas_laws said:
If the temperature changes and the number of gas molecules are kept constant, then either pressure or volume (or both) will change in direct proportion to the temperature.
Which means that as temperature drops, so does pressure. The converse is true with regards to a refrigerant; as pressure goes down (or up) so will the temperature, that's the basic principle behind which A/C operates. The cycling switch opens when the pressure is below 22-28 PSI and closes above 40-47, so that means if the pressure in the system with an even pressure on both high and low sides is under 40 PSI, the cycling switch won't close and the clutch won't engage. Simple as that.

Again, a quote from the FSM:

"Ambient temperature below approximately 7 - 10*C (45-50*F), during cold weather seasons, prevents the A/C cycling switch contacts from closing.
This is due to the pressure / temperature relationship of the refrigerant and the requirement of the system pressure to reach 276-324 kPa (40-47 psi) to close the A/C cycling switch contacts."

The defroster works in winter by heating the air, not by removing moisture. As the temperature of the air increases, its ability to hold more moisture does as well. The warm air carries the moisture away from the surface with a higher moisture content than the air, and the moist air passes out of the car. What good is blowing freezing dry air at a frozen iced over windshield? Evaporation is much faster than sublimation...

And besides, I have verified all this myself. When I had my system charged after I replaced the compressor two years ago, it was mid April and the temps were still around 40 degrees. The A/C clutch wasn't cycling then, but as the temperature rose things started to run. Same goes for now. It's 15 outside and the clutch isn't moving.
 
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