West Alabama British Car Club

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Club Happenings                                                                          by Allen Williams

What a great time we all had at Clyde and Betty's house last month. They literally "fell all over themselves" providing a great meal for all. Just ask Clyde to tell you the story! I think we also found out that Clyde is working on collecting more motor bike/scooters than George Barber. Betty took everyone on a tour of their home. A feature that was a real hit was the bedroom turned into a closet with some innovatively designed shelves.

 I don't have any news/gossip about anything this month. But, I do want to thank Eddie and Joann Davis for assuming the duties of the club. They are doing a magnificent job! A big "Thank you!" to all the other members who have helped by keeping mailing lists or helped make arrangements for events. Also, we need to thank each member family that has hosted and/or who has volunteered to host the monthly "meet and eat" event.

I do have some great useless information you can file away for future reference. Recently the A/C on my Explorer died. The compressor locked up in traffic spewing metal bits throughout the system. Since I'm such a cheapskate at heart, I decided to try to repair it myself (a $1500+ repair cost at a service center was a strong stimulant). I have learned a lot so far. The lesson for today is "how you're A/C system works". The following diagram shows a typical system and how refrigerant flows through it:

 Here is how it all works: The compressor does just that! It has an intake or suction side and a discharge side. Attached to the engine and driven by a pulley and belt system, it sucks in and compresses gaseous refrigerant. Then, it is discharged into the condenser (in front of the car's radiator). Heat is absorbed into the refrigerant during this process.

The condenser, which looks a lot like a radiator, is where the refrigerant is cooled to a high pressure liquid. The car's cooling fan helps do this.  As the compressed gas enters the top it's cooled and comes out the bottom as a high pressure liquid. The liquid then heads toward the evaporator inside the car, but must pass through a metering device such as an orifice tube or thermal expansion valve. The metering devices control the temperature of the evaporator (most desirable is around 32 degrees) by limiting the amount of refrigerant into it- too much and the evaporator freezes up, too little, not enough cooling. Condensers designed after the mid 90's usually have to be replaced along with the compressor if it suffers internal damage from seizing up.

The orifice tube  is the simplest and cheapest metering device. It is located somewhere between the condenser and the evaporator. This point can be found in a properly functioning system by locating the area between the outlet of the condenser and the inlet of the evaporator that suddenly makes the change from hot to cold. Although cheap to buy, they are expensive to replace because the system must be discharged and recharged.

The other common metering device is the thermal expansion valve, or TXV. It is commonly found on import and aftermarket systems. It senses both temperature and pressure. It is usually next to the evaporator.

The evaporator is where you feel the cool!. It provides several functions, such as removal of heat and humidity. The ideal temperature of the evaporator is 32° F. As the refrigerant enters the bottom of the evaporator as a low pressure liquid, warm air passing through the evaporator fins causes the refrigerant to boil (refrigerants have very low boiling points). This results in the absorption of large amounts of heat. This heat is then carried off with the refrigerant to the outside of the vehicle back to the compressor. Then the process starts over again.