i’ll start off with my car is a 80 l48 modified 350. it had non working A/C when i bought a few years ago and when i installed new heads i took it all out except for all the wiring. i’m buying all new parts which include a parallel flow condenser, and all new components made for r134,seals etc.

i have a high flow water pump paired with a cold case aluminum radiator, factory fan an a 180 stat. as well as a properly functioning vacuum system an water valve.

my question is there anything thing i should be concerned about with engine cooling or interior wise?

i live in north east connecticut so summers aren’t too bad

 

Other than check that fan clutch. No worries.

 

I would use a sanden compressor..the oem one draws some serious power. Do you have an auxiliary fan? Wire it to come on when ac on. I would add manual shut off valves too for summer.

good luck!

 

i already ordered a R4 style factory replacement compressor. 🤷‍♂️. as far as power loss i don’t plan on spritely driving while the A/C is on, so as long as it doesn’t feel like i’m driving a 4cyl i’ll be ok with that.

i don’t have the factory aux fan but have been debating on adding it. would it be that much help?

 

In your climate, with your mechanical driven fan running all the time I seriously doubt you will need it.
If you do decide to install a supplementary electric fan I would then replace the factory low pressure switch with a more modern trienary switch. Then trigger your fan relay off the trienary switch. Like a modern car with electric fans. Then the electric fan will only run when needed.
I don't have a mechanical fan at all. Only electric fans. Very rarely does my air-con actually kick the fans on. And I live in a much hotter climate.

 

ok thanks. yeah it hit high 90’s last summer and the temp gauge only went up too 190ish just below 200 so i hope it’ll be good.

i’m more or less concerned with the a/c not being cold enough but i went with all new components made for r134 so i should be good right?

 

I converted my 82 to 134 and installed a parallel flow condenser. I was blowing 46 degrees out the grill during 95 degree south Louisiana summer days. I did wire my auxiliary electric fan with an additional manual switch and kept the engine temp switch. That way I could run the fan if I felt it was necessary, like in slow moving traffic.

I have a Vintage Air system in my 75 now with the Sanden Compressor now. You should consider just returning the R4 compressor for a refund and contact Vintage Air about the Sanden with mounting kit for your car. It is SO much nicer driving with the Sanden.

Either way, the parallel flow is the key. You will
be fine if you pull a good vacuum, use the right oil, and get a proper charge.

 

There are no new reliable R4 compressors.
Even the new Delco ones are not what they once were.
That design had o-ring case seal problems even when brand new, back in the day.
That is the reason GM did not use that design for too long.

The rebuilt ones are extremely unreliable, the cores are all worn out.
I would return that thing in a heartbeat and put a sanden on.

My local corvette shop will not even work on an R4 and guarantee for it to continue working......

Change it over to a cycle switch style system while you are at it.
There is a retrofit accumulator available for that.

 

ok. i just got off the phone with vintage air an the salesmen told me that the sanden compressor won’t work with any factory components and that i’d need to buy there complete kit?.. 🤷‍♂️

 

Well of course they want you to buy their complete kit! $$

It is very complete and does work very well.

But if you already have a lot of the major components, you will need a bracket kit to mount the sanden compressor.
IIRC it may be old air products that makes one. High & wide IIRC.

I have used this one: I believe Vintage Air uses exactly the same compressor and brackets.
https://www.oldairproducts.com/produ...mpressor-mount

You will also need an accumulator set up for R134 and clutch cycling. A stock setup for an 80 may already be there and work. But a new one for a fresh dessicant bag is required. Here is an aftermarket conversion one:
https://www.oldairproducts.com/produ...ir-eliminator/

Note that even once you get all the major components, this is not a bolt-in conversion. With the sanden you will almost certainly need an AC hose shop make you some custom hoses. But it will run well and work well for years vs the R4.

 

That salesman is just trying to make money.
An awful lot of us are running a Sanden or sanden copy compressor.
I run a sanden, parallel flow condenser, aftermarket evaporator, custom made hoses, (any automotive air-conditioning shop can crimp them for you) And cycle mine with a adjustable temp switch with the probe right on the line going into the evaporator box.
Everything else is factory other than a trienary switch replacing the low pressure switch. It's very cold and I live in a very hot climate.

 

yeah i’m researching now about what i’ll need.

so you can’t use a factory style evaporator with the sanders type?

 

sure you can!

 

I'm in a hurry here as I need to leave for an appointment so this is going to be a shotgun of various tidbits and not something well organized. Take it for what it is.

I'm not sure I'd agree with New England weather not being too bad these days (I'm in southern NH). Maybe 20 or 30 years ago it seemed you'd need AC for 2 weeks in August. Now I run my AC in the cars 95% of the time. So AC is very important to me and must cool properly and be reliable. For my Corvette I went through the entire system and refurbished is 5 years ago with all stock components. The compressor that came on the car was junk because the previous mechanic didn't change the fouled orifice. So I replaced the compressor with a NEW production Four Seasons brand R4. The AC is still working to the same values 5 years later. I haven't touched it since. Never ever buy a "Rebuilt" compressor! Never. Most of what is "rebuilt" are just sloppy spray paint jobs. They are so bad.

There must have been 10's of millions of R4 compressors installed during their run a being the "current" go to compressor for so many brands of cars, trucks, and heavy equipment built all over the world. You can pressure test an R4 before putting it on the car so as not to waste your time and materials. Note: In the 1980s the R4's changed over to Metric threads for the holding bolts. Since them ALL new R4s ship with Metric holes. Check your bolts and the R4 holes with gauges to verify the threads. Metric vs SAE with be VERY close so be meticulous with this or you will be plagued with a slapping belt, high head pressure shakes at idle, etc. My car is stock so I used the stock bolts and simply Helicoiled the R4''s holes for SAE thread.

You should be able to achieve 40-45 degrees out the vents with R-134 or perhaps lower with that parallel flow condensor. Yes, the newer Sanden 5-series compressors are better than an R4 but you will need to spend some time and effort adopting it to your system. New production R4s should have a better design shaft seal. Think of it as an engine where you put a new carb on it and then must time and tune to make it work effectively. Most people won't have the knowledge or tools to dial in a different type of compressor or even a different value orifice tube.

You car is already a CCOT air conditioning system. That is a Cycling Clutch Orifice Tube. The orifice is the throttling valve for this type of system which is what converts high pressure liquid to low pressure as it enters the evaporator core where it will boil and turn to vapor. The orifice typically gets changed to a different model of orifice that throttle R-134 properly. You will also need a new accumulator (down behind the dog leg of the passenger fender) as it will be full of garbage and incompatible oil for R-134 refrigerant. An Flush the system backwards using a proper AC flush solvent NOT "any" solvent.

There is so much to say but I'm out of time. Be very meticulous with your work and the many details. This isn't an automotive thing is Chemistry. You can easily achieve a cool pleasant C3 cabin in 95 degree weather in New England whether cruising back roads or spending all day on the highway. I know I'll catch some flack for saying that but it IS my experience.

Goood luck and soon it will be Corvette weather here again!

 

I agree with the Four Seasons assessment above.
I have had good luck with them.
If you are going to stick with an R4, that would be one of the only places I would get one from.
It certainly would be simpler.

 

i’m still debating on going sanden but i’m glad four seasons is the compressor i got. new not referb

 

I’m on #2 napa’s best new r4…under warranty but i lost some r12… 134 much cheaper , stock up at walmart while u can. I would still consider the sanden. The r4 is very noticeable when on and just cruising you are very aware it’s on.
but im a 4 speed with no idle kickup on a 79 l82. I cannot compare to autos with idle kick up.

 

I put in all new ac on my 81 and here are a few tips. I got all parts from rock auto except pressure switch and it came from Napa. How much refrigerant and Pag oil is key. 36 oz refrigerant and 8oz Pag oil. Make sure your carb kicker is working and bumps idle up to about a 1000 rpm when you engage ac also oil your O rings and don’t tighten them to tight. I didn’t know anything about ac until I put mine in and it’s not hard. I get 36 degrees all day and I live in Tex. There is a great read on this forum if you look for it. He had all the proper measurements and pressures. Good luck

 

It is totaly doable at home, and you can easily wind up with as good or a better job than the "pros".
They are always in a rush.
Take your time.

It is chemistry, not mechanics. So my advice:
Vacuum it down for along time, like an hour, make sure it holds, for another hour.
Otherwise re-check your o-rings etc. til it does.
Once it holds, or immediately before, makes sure it has new dessicant. That is very important for it to live long.
Add a little freon, and then have it sucked out, and back down to a vacuum again.
The vacuum is so important.

Then add the correct freon amount using a kitchen scale to weigh the cans.
Make sure it pulls down to near 29psi before the cycle switch trips.
I wound up using an adjustable cycle switch, and tweaking it.
32* inside the vent with a IR gun, 36* at the vent, on high.
Add a few ounces more, or less, and see if it gets colder at the vent.
If it does, believe what the car wants.

I like it freezer cold.
Do not listen when someone else tells you it's "good enough"
There is no reason to settle.

I had a car once that would never go below 50* at the vent, and it made instant "fog" inside the car a couple times, and almost killed my family, at 70mph. Scary as ****
The pros said "that is all it does"
"We did it by the book."

I said throw the book away!
I gave the car what it wanted.
I fixed it, 32* !!!!

a Retired Chemistry Teacher

 

yeah i got most of the major components from rock auto an accumulator an hard line from old air. rock auto had the parrell flow condenser which came in today.

im gonna roll the dice and stick with factory for now. 🤞.

will see how bad engine drag will be. i have right around 375hp out of the motor and 3:54 gears.