But after that headache, I filled the system with 8.5oz of UVPAG150, I pulled a vacuum on the system and had one small leak on the cycling pressure switch. I fixed that, sucked it down for 35 minutes, it held vacuum for 12 hours and after seeing that I charged it with 2.45lbs of R134A. The air in the car got very cold and I was pleased…. Until I took it for a test drive.



The idle was a little low, and this was not surprising at all so I went around the block, and pulled over to bump the idle screw up. I did, so park idle was about 900. One more ride around the block and now the car wants to idle at 1700 regardless. I ended up blowing the carb apart, cleaned out the usual areas and reassembled, this solved the issue.
Temps out of the dash are great. Very cold, cold enough to make me actually turn down the AC while I was driving. It's comparable to my avalanche, which I clocked at 27 degrees one time.

Worth it? Definitely. Now I can cruise to school in the coolest car, and feel as cool as I hope I look.

 

 

Couple small changes, gonna be a few of these posts because the air conditioning has put a magnifying glass on some issues

Issues like voltage

my car has a CS144, but the stock fuse box can only put out so much because of its design. I also have a C4 corvette blower motor, which I think draws more power. With the headlights, wipers and AC on, voltage in the car drops to around 10 volts which doesnt make me happy. To get around this, and kill two birds with one stone I put in a 5/16 bus bar which Ive needed to do for awhile. The bus bar splits the 6ga feed from my cs144 and gives me two posts before my 80A maxi fuse by the starter for the car. I designed the circuit with this in mind for electric fans bur I never put the bus bar in till today. I hid it in the drivers fender well, and I added a relay to the ac clutch circuit to take some load off. Obviously the relay is fused as well. I also ran the sense wire from the regulator to the bus bar so the alternator can get a better idea of how to regulate. Much better now. Even with a heavy load voltage in the car is around 13.3 and a solid 14.7 at the bus bar

New setup

 

There was an incident where the two crash shocks in the back were compressed. It was not my fault, and there was nothing I could do about it. Thats all I'm saying because Im still rather angry about it.

But nonetheless, it was a zero dollar fix and the bumper has no damage at all, stress cracks or otherwise

 

Replaced my ac belt already for a cog belt. Took all my belt deflection away.

 

Added an idle compensator solenoid to help with the idle in traffic. My carb is numbers matching and the holes were not tapped. Kinda odd.

 

Changed to a 160F thermostat. with air conditioning, this car gets hot very quickly. It will need electric fans before the spring no doubt about it. To anyone reading, any suggestions on fans would be appreciated. I know spal is very popular, I'm also considering a 96 c4 set. all I care about is I want the engine to stay at 180 and I want the ac to be cool on 90+ days in standstill traffic.

 

Added the 77-82 dome light. Its not a totally correct install, because mine isn’t indented into the headliner, but its there and I like that. I also put a switch to turn the light on or off independently of the rest of the interior lights for reading, working or eating. While I had the interior trim out I dyed all of it to bring it back to a nice firethorn red and not a faded dirty maroon

 

Re did the switch because V1 was too tall. Modeled a quick bezel to adapt to the newer, smaller switch.

 

Also dyed all the rest of the rear window/seatbelt trim. It was worth it. Now all the plastic matches. I also changed the two under-dash bulbs and the 578 bulbs to warm light LEDs. They’re a little brighter, draw less power and still give that warm inviting glow to the car just like the incandescents did.

5 minutes around the neighborhood and the dome light is already a clear winner. I needed to look at my multimeter for a charge issue and just flipped the switch, boom. Whole interior lit up.

The beauty of having a dedicated switch for that light is that I dont need to have the footwell and cargo lights on to have the dome light on. So its kinda taking the place of my old map light. Makes it easy to read something in the dark or find something that rolled away, not to mention a thousand other uses. Very pleased.

I should also mention, I did copy this idea from the internet, there was a website called my 76 blog and he had done this but without a dedicated switch. The switch is my own touch. To place my light I measured a friend’s dads 79. The hot and constant ground come from the jack compartment and the switched ground comes from the cargo light

 

Finished product

 

Added a relay to the ac system to take the load of the clutch off the fuse box and mounted two extra relays for my dual spal fan setup. I managed to score a used set off Ebay, they will be here by next week. The two relays are 10gauge to the starter ,fused 30A, and 10 gauge to the fans.

Brackets and bolts will be painted black inside and out to further hide them

Couple of stray wires for some things to be cleaned up yet, but the majority are loomed and protected

 

Had an issue where the CS144 would drop out randomly. I believe either the regulator/diodes are damaged or the SI to CS plug was iffy. Cleaned the contacts on the SI harness and the problem has seemed to go away but Ill be watching closely.

obviously cant have an alternator that wants to drop out at idle or under load if Im about to put 60A worth of fans on its back

 

I had mentioned a few posts ago that I replaced the starter solenoid cause “I broke it”.

Quick breakdown of that

The direct drive starter uses a 3/8ths stud, and it can take a fair amount of torque

The gear reduction starter has smaller posts and apparently cant handle much at all, cause when I installed this in July I just instantly ate the threads off the solenoid. I was able to kinda tighten it, so I left it knowing that I would need to go back to it, and that happened to come around when I needed to reroute my charge wire to go around the accumulator.

Moral of the story? Use basically an open end wrench on gear reduction starters. Learn something new every day I guess. Sometimes those lessons are expensive but you just gotta roll with the punches.

 

I have been working on the fan installation although they have yet to arrive. As I said, I mounted my relays and a bus bar in the fender well. I had several changes of heart from version 1 to version 6 on routing, gauge, power source, everything.

The final system is more or less how I drew it up in the first place. 2 10 gauge short wires, each fused 30A to the relays (power) 12 gauge to the ACC terminal in the fuse box, (trigger) 12 gauge to the thermostatic switch (ground) and 10 gauge to the fans (load). Initially I set out to use 12 gauge everywhere cause that's what I had on hand, and it should be able to handle the current but I felt more safe with a big overhead for amperage. I experimented with getting power from the starter vs my bus bar off the alternator and I settled on the alternator side. I had heard many things about the fans killing the voltage regulator because of their startup load, but I just think this is a better way to go for me. My alternator is high enough amperage for it, its not like I'm using the stock 63A. The beauty of having it on the bus bar is two fold. 1. The sense wire is also on the bus bar so having the fans on drops the voltage 0.1 vs 0.7 on the starter side. 2. My charge wire is fused 80A and while messing around I was able to make that blow open because of the load coming from the alternator. Having it on the bus bar puts it before the main fuse.

I ran my test fans for 2 hours, cycled them on and off many times and observed voltage at many places throughout the car during each test

I'm confident in how the circuit is set up, and happy with the wiring job on it as well.

I’m working with a close friend in a welding course to make up custom aluminum brackets for the spal fans.

I put the temperature sensor in the intake, but I don't like where it is so I'm going to be moving it to the passenger head.

 

I changed my 77 horn button to an aftermarket emblem so its cross flags are more like the 76 style. Im not sold on it but for now, its ok.

 

Fixed the issue where the CS144 would drop out. Turns out it was the SI/CS plug. All I did was remove the plug and crimp the lamp wire directly to the CS regulator harness

 

Been thinking of deleting the EGR, and one night I woke up and came up with an idea. I bought a junk valve, welded the blockoff to the bottom and capped the lines internally. Looks correct but the EGR is now blocked.

 

So, I drove my corvette every day for three weeks with air conditioning and although I loved every bit of it, I immediately saw room for improvement. I put a 3-row aluminum radiator in it a year ago and that has always been more than capable of cooling my L48 even on the hottest of days… before I put air conditioning in. Ever since the AC I have 5-10 minutes in standstill traffic before it reaches 210F and it takes a long time to cool down once it gets hot, like several miles at 40 mph. I had a 180F tstat in it, so I swapped for a 160 which helped but not much, especially when it got over 200 degrees. I decided there was only one way to fix it, and that way was electric fans.



About a year ago I bought a set of 3800II Camaro fans from the wrecking yard and found they were ¾” too wide to fit in between the A arms, so I sat on the idea. This time around, I started looking for options, and I had a few choices. C4/5 fans, ford Windstar/MKIV/taurus fans, or the dual spal 11” fan setup. The c5 fans seemed to be the same size or close to it as the Camaro fans I have so I was weary of those, and the ford options seem to draw a ton of amps, like up to 90 on startup. I did not like the idea of that kind of draw on the system



So, it was settled. I wanted the spal dual fan setup which was out of stock at a few venders I looked at. By pure luck I landed an eBay sale for a used set. While they were on their way, I made several revisions to the charging system which you can see in prior posts. I’m happy with the relay and wiring setup. I used a 185/175 temperature sensor in the passenger head to trigger the fans and I also have a relay to turn the fans on regardless if the ac is on.

I needed brackets and I wanted aluminum, so I called a close friend who is studying to be a welder. We took some measurements, bought some material and the next day he and his welding class tig welded my brackets together as a sort of class project which is cool.



I bolted the fans to the brackets with 5/16 bolts and self-tapped the assembly to the radiator. I had several fitment issues, but I figured it all out and got the fans and radiator in the car. I had to replace my power steering pump again, which only has maybe 150 miles on it because it was already leaking. I tried to rebuild it, but once I was inside I found several things I didn’t like so I just changed it again.





I also took this opportunity to put in a new upper hose, thermostat and water pump, which is now an aluminum high flow unit.



When I did the AC, I realized that my lower heater hose was in the way of the R4 compressor, and I didn’t like how the AIM said to run the lines, so I changed over to a 79-82 heater S tube which is a hardline that goes under the compressor. I wire loomed and zip tied everything to keep it looking good and organized. I am very proud of how it all turned out. I started to test drive and so far, so good.

 

finished product