Factory AC rebuild/upgrade
 

While I'm waiting on my block and heads to get done at the machine shop, I figured I'd go through the AC system while its easier to get to everything.

My car is a 1980 Trans Am with a complete AC system from a 1979 car with a stock 400 motor.

The AC worked well before the motor came out but suffered from the lack of air volume everyone complains about. I drove the car to STARS in Florida one year and it kept us cool coming back through Alabama and Mississippi. It helps to park in the shade or I now have insulated foil sunshades which help a bunch. Just takes so long to cool a heat soaked car down.

While the motor is out I have removed the suitcase. It has some debris in it which I will clean out. Also inspecting it for any air leaks. Is there a performance upgrade to be had replacing the evaporator coil? It will be getting a new accumulator and orifice tube when it all goes back together. I've read all the posts I can find on an upgraded fan and it does not seem like there is a consensus better bolt in fan?

I plan on a new parallel flow condenser and a pro6ten compressor as my compressor is flinging oil under the hood.

I'm pretty impressed with the factory system other than the air flow. My son was just given a 79 camaro and the air wasn't working. Found the leak the AC shop missed and played with the charge. I've got it blowing 33 degrees out the center vents on the highway and 38 at idle in the driveway. Factory system completely other than converted to 134A.

Looking for input on the best place(s) to get the parallel flow condenser and if I missed anything on a better blower fan.

I seriously looked at Vintage Air and couldn't bring myself to change out everything.

Thanks in advance.

Original Air (part of classic auto air) sells the parallel flow condenser I believe. And they have kits that are essentially an under hood upgrade if you were interested in that. They come in three stages but the stage 3 includes everything from the evaporator to the condenser including a sanden compressor. I just ordered and am waiting on a stage 2 which excludes the evaporator core. It may be an option.

As far as the air flow, I’ve only ever owned my 77 and never had AC on it to compare but I sealed all of my duct joints with foam to try to prevent leaks. I feel like it improved the airflow at least a little. It may not be comparable to modern vehicles but I think it’s better than it was.

In 1978 I had a 75 Camaro in Florida for over three years and the stock AC system always seemed to work at peak to try to keep it cool.
My 72 Lemans I just did a frame off, I replaced the whole system with Old Air stage 3 as mentioned and just had it charged. It works way better than I could have hoped for. It blows well with the stock fan and uses all my original inside workings which are stock AC. I've never messed with AC before and I installed everything myself. It was a direct bolt in system and I had no issues when it was evacuated and charged.

The key to having good A/C in a Firebird is to make sure all your under dash duct work fits properly and is thoroughly sealed. Having these cars for 40 years and have battled exactly what you are talking about i figured out years ago that the factory ductwork was never an ideal design. My Firebirds have excellent A/C after the careful and painstaking task of having all the ducts installed and sealed properly.

Got the suitcase all cleaned and gone through. It is ready to go back onto the firewall. Took about an hour of gentle scrubbing, hot water rinses, and air hose blowing to get it all cleaned without totally disassembling.

Before I get it back on I'm going to test all of the cables and vacuum lines to make sure its working as it should. Then the dash will come off to get to the heater core.

Just curious, how was getting the suitcase out?

With the motor out and the inner fender out, it came out nice and easy. It came out 18 years ago when I rebuilt the car the first time. Putting it in, most of the holes for the original threaded screws were wallowed out. I had to go to a 5/16 thread cutting screw to get everything to tighten down. I tested the blower fan today checking for air leaks around the suit case. I have a small air leak either around the lower heater core pipe or the bottom of the suit case. I couldn't tell for sure. I'll pull the tire so I can get in there better and run a little more sealant across the bottom of the suitcase to be safe.

The fan was a little noisier than I'd like so I'll replace it while I can get to everything. Looks like the VDO PM 105 is the standard replacement???

This place sells parallel flow condensors

https://www.ackits.com/parallel-flow...ine-condensers

https://www.ackits.com/parallel-flow...ine-condensers

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I can tell you getting the suitcase sealed to the firewall is a royal pain. I thought I put a fair amount of sealant on the case before bolting it on. When I hooked up the fan to test it, I had numerous small leaks. After 90 minutes, I was able to get it all sealed up and sucked the fresh air vent closed and tested it. Huge difference in air flow in the cock pit. I could put my hand even with or behind the head rest and I could feel air flow from the side vents.

When I pull the dash and check the seals on the interior portion, it should be more than acceptable for a part time driver.

I tried the PM 136 fan and the blade was 1/2 to 3/4 too short compared to the original. I didn't think it would seal tight enough to the firewall so I didn't even test it.

;) watching this...... same car same issues just not on the to-do list yet. I plan to open up the suitcase since the motor is out replace the heater core and clean everything.

The main weight holding "bolt" for the suitcase is directly above the motor. This is a "stud" that has sheet metal threads for firewall and machine threads for the suitcase.
Almost always the whole thing comes out as one and strips when you go to re install.
I have a fix for this Without going to bigger hardware for "wallowed out" holes.
For the studs I put a speed clip on the inside of the air horn area of the firewall and tighten the stud to it. The clip doesn't clip on anything,
It's just a sheet metal screw 'nut" doing its job. May have to hold it with pliers, but once its tight, the machine nut area works as intended, No bigger holes or hardware.
THis will NEVER pull out or strip again.
Now you can use the machine screws to even out the suitcase and evenly tighten it.

I’m revisiting this as I just installed an Original Air kit on my 77 T/A and was wondering if you would kind elaborating on how you played with the charge on your sons car to get vent temps that low. Mine are decent but I feel like there is room for improvement.

My issue with the Original Air Group's kits are the bracket for the compressor, more so, the adjustment 'T' they use. It's a 'T', where the long part is threaded rod, tacked onto a piece of tube that supports the side of the compressor entirely by that threaded rod, it vibrates, and breaks in short order.

I had that problem with the kit on the 442, went through 2 of them in about 25k miles. The same config is used on their' other kits.

So I bought the Vintage Air bracket, and replaced theirs' and all is fine.

Another thing, some cars use a vacuum switch(es), and doors, to actuate stuff like duct switching and heater coolant flow, AND, those suck. (No pun intended). I went through all the lines, diaphragms, switches, etc on the 442, and here I am now getting ready to swap it over to a Vintage Air setup.

IMO, if you are starting fresh, and not doing a concourse resto, go straight to the VA setup. (Sorry for the rant, but some may need to hear it)

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No, I can agree that at least after installing the Original Air setup I wouldn’t go that route again if I had to do do it over. I’m not overly happy with the install process with the kit, the form and function of the brackets as you mentioned, and essentially non-existent customer service.

I liked the idea of it because all of my HVAC ducting and blend doors and controls were in tact and useable. I didn’t and don’t want to replace everything with VA components. Especially the controller as dumb as that sounds. I may have to look into that VA bracket though for the compressor. .

Are you talking about this VA compressor bracket setup??

http://www.vintageair.com/images/141001-PPA.jpg

Will this work with the OA compressor? I don't see that same bracket in the Stage 3 kit I ordered...wait, is that the T already installed in the bracket?

https://www.originalair.com/images/t...8-stage-3.jpeg

Yes, it's already on the bracket in that pic.

And yes, that's the VA bracket I was talking about. The VA bracket stabilizes the compressor better, and prevents the 'belt wobble' by a lot.

The VA setup uses solenoids, there's no vacuum components, much more reliable, and with the hoses over the pieces of plastic tubing the OE stuff is, you get much less leak. The blower on the VA setup blows hard, too, way better than the factory setup.

I duct taped the OE plastic pieces prior to switching to the VA setup, closed all the gaps, that helped a lot.

The VA setup is entirely contained under the dash, and easier to service if you had to. The only thing with the VA setup that I don't like is the firewall cover plates, but I did smoothie plates anyway. Except the 442, that will have to use the block off plates until I get around to doing a smoothie plate.

One thing with the VA setups, screw putting all the hoses through the kick panel area, use a manifold, and go through the firewall off to the side. Wish I would have done that on the GTO, may go back and do that at some point.

VA has kits for the AC hose and ends that are reusable AN type (Eaton/Aeroquip), that's the way to go, you can make them at home, and route them anyway you want. I don't care for the routing that is forced by using the premade hoses in the default kits.

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Here's how those hoses look on the GTO, with the Billet Specialties compressor manifold:

I used some of VA's premade hard lines too.


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Stupid pic-flip thing....

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