Chevrolet, Uncategorized

Connecting a Serpentine Belt System to Factory Air in a 1970 Chevrolet C-10

We’ve been working on classic cars for several decades now, so we’ve got a good picture of the quality of thousands of different parts made by scores of manufacturers. If we see that you’re working with equipment of dubious virtue, we’ll let you know, as this customer discovered.

I installed a serpentine belt system with an R4 compressor. What is the best way to hook it up to the factory A/C system? I would like to convert the POA to the cycling system and will need to make the necessary changes for the 134a switch.

Assuming you wish to use the R4 compressor, a simple hose adapter for the back of the R4 allows it to accept our standard hose fittings. We can supply the adapter and hose materials/fittings to build your hoses to fit the R4 to the stock A/C system.

We also offer a kit to convert the R4 mount / serpentine belt setup to use a modern rotary compressor in place of the R4. This is highly recommended since the R4 compressor is arguably the worst compressor General Motors ever used. R4 compressors not only have a tendency to leak regularly at the shaft seal and around the body, but also to fail prematurely. This is so problematic that virtually no one in the industry rebuilds them anymore, and some distributors won’t even warranty brand-new compressors.

With our conversion kit, you can install a standard rotary compressor on the original mount with just a couple of adapters, and reuse the rest of the factory equipment.

In a truck like yours, the original POA valve is designed to operate at the lower pressures that R12 operated at. We rebuild these valves and can calibrate them for 134a. This keeps the system stock and does not require any modifications to the existing evaporator unit or the installation of a cycling switch to keep the evaporator core from freezing.

If you drive this truck in traffic, it is also very important to upgrade the condenser to handle the increased heat load on the system. The condenser is the heat exchanger for the system, which mounts in front of the radiator. The stock tube-and-fin pattern condenser is designed to work at the lower R12 pressures, but when you convert to 134a, the old condenser can have problems with the additional heat and pressure that 134a generates. This means the system pressures will rise in hot driving situations. The air coming out of the vents in the car will warm up — you can lose 5-10 degrees of cooling capacity by not addressing the stock condenser. We offer a parallel flow condenser kit for the C-10 that uses a 134a-compatible condenser for proper conversion to 134a.

When you charge the system, you will use approximately 70-80% of the original charge the stock A/C system used, which was 3.75 lbs. of R12 (for a 1970 Chevrolet C-10).  When running 134a, therefore, you will use 42-48 oz.

When you’re ready to upgrade your various GM factory air conditioning parts, give us a call and we’ll get you fixed up!

 

Related Posts

Leave a Reply

Your email address will not be published. Required fields are marked *