1979 454 C10, Factory Air

[JBswth]

Howdy. I know this is my first post, but been using the forum for over a year to work on the 1979 C10 Big10 I bought out of a field in eastern CO last year. I have searched the forums have read up on the pros

I absolutely love the truck. Shamrock Green Metallic, 454/TH400, 8' bed. Silverado, factory cruise, A/C, but manual windows. I bought it non-running and have put about 10k miles on it in the last 12 months.
The factory air system is partially intact- the condenser and the evaporator are there (in unknown condition)- but the compressor, accumulator, and hoses are gone. I am unsure if this had an axial or radial compressor- I see conflicting info on LMC truck as well as the forums.

I want to add A/C back this spring, but am debating what route. Do I get a modern kit from Vintage Air, LMC Truck or Classic Auto (that uses factory ducting, not underdash), or do I build the system with factory components? From a quick look, Rock Auto and or LMC should be able to get me all the components and it would be a good bit cheaper than a Vintage Air or similar kit. Welcome any input or suggestions from people with experience here.

I would stick with factory AC, and I would use the A6 compressor.

J. B.

 

[Ovals_and_Bowties]

You could run a 100% bone stock factory setup no problems.
R290 aka propane will run in an R12 system as a drop in replacement but the EPA doesn't like it.
There's a couple other drop-ins as well.
Enviro-safe makes an R12 drop in.
ZeroR makes a R290 can with 134a fittings on the top :wink: there are thread on R12 to R134a adapters one can buy off rock auto :wink: .

 

[1979big10]

Here’s where I am at-
Sanden 508, modern parallel flow condenser, that runs into a vintage air drier, into an expansion valve, into the factory GM evaporator, which should then run to the suction side of the compressor. I’m eating for an adaptor for the evaporator to suction hose, but I want to make sure that I don’t need to be running a factory type accumulator tower with the OEM evaporator.

Thoughts?

 

[bucket]

Why the Vintage Air dryer? Why didn't you just choose an original type accumulator to begin with?

 

[1979big10]

Why the Vintage Air dryer? Why didn't you just choose an original type accumulator to begin with?

Because I didn’t know better. This is my first time messing with an A/C system at all, and was advised towards that dryer. No issue not using it and putting a factory style accumulator on it.

 

[75gmck25]

I have always used a factory-style accumulator (or filter/drier) in the stock location, but I assume the VA part does the same job.

Did you describe your components in slightly the wrong order for the connections?
- The compressor has a hose running over to the accumulator, which is then directly mounted on the evaporator. The other hose from the compressor runs to the condenser.
- the 2nd hose from the condenser runs over to a fitting near the bottom of the evaporator, and the expansion valve is inside that tube.

Some detail you may not need:
The original condenser-to-expansion valve hose for my ‘75 was an odd design. The hose ran across the top of the radiator support, so it was a very durable (like a reinforced garden hose) small diameter hose. Then at the evaporator/expansion valve they had to use a large diameter connection (7/8”?) on the hose so it could fit over the expansion valve.
The guy who made my custom hoses had to braze two fittings together to make it work, since the stock hose ends he had didn’t allow for using a small diameter hose with a large diameter fitting. He just cut the old hose fitting at the evaporator in half and brazed the correct crimp fitting for the new hose on the old threaded connector. There may also be an adapter that serves the same function, but he did not have one.

The factory mounting of the accumulator has it mounted on the evaporator at the top, and the other accumulator fitting comes out the bottom. There is then a second piece (just a tube) that makes two 90 degree turns and ends up pointing straight out at the radiator. My A/C guy used a different GM accumulator that had all fittings at the top, so the compressor hose fitting on the accumulator pointed directly at the compressor. It made the hose routing more direct, but that is all I gained.

 

[Scruffy49]

Go as factory fitting as you can. Currently switching an 85 with V-belts for a 92 serpentine belt system. Switches the location of the compressor to the passenger side, alternator to the driver side. Had to cut the 85’s hoses with a sawzall, fittings just twisted the lines trying to remove them. Will be retrofitting the condensor and drier (canister?) as well. Factory in dash ducting and controls staying 1985.

Probably easier to go with an aftermarket system, but, they never seem to fit/cool correctly.

 

[1979big10]

Did you describe your components in slightly the wrong order for the connections?
- The compressor has a hose running over to the accumulator, which is then directly mounted on the evaporator. The other hose from the compressor runs to the condenser.
- the 2nd hose from the condenser runs over to a fitting near the bottom of the evaporator, and the expansion valve is inside that tube.

No, according to every diagram I have read (with a drier/expansion valve as opposed to an orifice tube/accumulator) the system flows like this-
Compressor>condenser>drier>expansion valve>evaporator>suction line back to compressor.

The factory system went compressor>condenser>orifice tube>evaporator>accumulator>suction side of compressor.

 

[1979big10]

Thanks for the help, going to put a factory accumulator on it instead.

 

[bucket]

No, according to every diagram I have read (with a drier/expansion valve as opposed to an orifice tube/accumulator) the system flows like this-
Compressor>condenser>drier>expansion valve>evaporator>suction line back to compressor.

The factory system went compressor>condenser>orifice tube>evaporator>accumulator>suction side of compressor.

Yes, you have those correct.

 

[Turbo4whl]

Early Squares had a Fridgeaire pump and a POA valve. They did not use a recycling pump clutch, when you turned it on the pump was always on and the POA valve kept the evaporator from freezing. These systems got very cold! Here is some info:

POA – Knowing These 3 letters May Help Keep Your A/C Evaporator From Freezing!​

• October 7, 2022

All air conditioning systems have something built into the system to prevent your car’s evaporator from getting so cold that it freezes. In some systems, this mechanism is a thermostat. However, in most mid-’60s to mid 70’s GM vehicles and some 70’s Ford vehicles, it’s a POA (Pilot Operated Absolute) Valve.
On older cars with a POA Valve type system, the Compressor runs continuously whenever the air conditioning system is operating. The valve prevents the Evaporator from freezing by bypassing excessive system pressure. If you have little or no cold air coming out the vents when the A/C system is operating and the high side reading is normal but the low side reading is high, you may have a failing part. The same goes for if your evaporator is freezing, chances are good you have a failing POA Valve.
Depending on the model, General Motors cars & trucks used POA Valves made by Frigidaire or Delco. While Ford used one of nine different Delco-manufactured POA Valves. If you have a Frigidaire POA valve, you are in luck…it can be rebuilt. Unfortunately, Delco valves cannot be rebuilt.

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Whether you are looking for FAQs, repair service, or replacement POA valves for GM or Ford vehicles, you can count on Classic Auto Air!

This system can be converted from R12 to 134A with outstanding results. 100 years ago, or it seams like that, I took a 2 night class learning how to do the conversions.

 

[bucket]

Early Squares had a Fridgeaire pump and a POA valve. They did not use a recycling pump clutch, when you turned it on the pump was always on and the POA valve kept the evaporator from freezing. These systems got very cold! Here is some info:

POA – Knowing These 3 letters May Help Keep Your A/C Evaporator From Freezing!​

• October 7, 2022

All air conditioning systems have something built into the system to prevent your car’s evaporator from getting so cold that it freezes. In some systems, this mechanism is a thermostat. However, in most mid-’60s to mid 70’s GM vehicles and some 70’s Ford vehicles, it’s a POA (Pilot Operated Absolute) Valve.
On older cars with a POA Valve type system, the Compressor runs continuously whenever the air conditioning system is operating. The valve prevents the Evaporator from freezing by bypassing excessive system pressure. If you have little or no cold air coming out the vents when the A/C system is operating and the high side reading is normal but the low side reading is high, you may have a failing part. The same goes for if your evaporator is freezing, chances are good you have a failing POA Valve.
Depending on the model, General Motors cars & trucks used POA Valves made by Frigidaire or Delco. While Ford used one of nine different Delco-manufactured POA Valves. If you have a Frigidaire POA valve, you are in luck…it can be rebuilt. Unfortunately, Delco valves cannot be rebuilt.

You must be registered for see images attach

Whether you are looking for FAQs, repair service, or replacement POA valves for GM or Ford vehicles, you can count on Classic Auto Air!

This system can be converted from R12 to 134A with outstanding results. 100 years ago, or it seams like that, I took a 2 night class learning how to do the conversions.

Yes, my Chevelle does great with r134a. That POA valve does a great job of keeping the air out the vents at 33° too.

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