Ac help for ls3 conversion in 71 camaro with factory ac

[Tomcuschieri]

Hi I’m getting ready to install an LS three 525 in my 71 SSRIs Camaro with stock air-conditioning. I’m just trying to figure out what parts I can use off the old AC system to run with the new air-conditioning system.I assume I need to pull the air conditioning box off the firewall to fit the LS three is that correct.? Thanks for your help

[p51mus]

the best thing for you to do is scrap all the old system which is R-12 and no longer used. Go with a complete Vintage air system. Save yourself a lot of grief. And it will cool better than the old junk also.

[ULTM8Z]

Agreed... the newer stuff is lighter, more compact, and more efficient.

[Tomcuschieri]

Thanks guys. I did have it converted to r134 about two years ago. So I can still use the new condenser and dryer at least right?

[dhutton]

Any time you open a system the drier should be replaced. You can likely use the condenser, it is likely larger than the VA condenser.

Don

[parsonsj]

Right, what they said. Get a complete VA kit. You might be able to salvage the condenser, and that'll save you $75 or so, but that's not really worth it for later troubleshooting... "I wonder if it's the condenser...".

[69 Ghost]

If you are looking to still do your factory conversion PM me and I can help you. The factory units are waaaayyyyy better than any aftermarket you just need to modernize some components.

[TheBandit]

I am running factory AC on my 70 Nova with an LS engine. It's doing a great job keeping me cool, although I live along the Southern California coast where it only occasionally hits triple digits. I think the factory system gets a bad rap because most systems at 50yrs old are in a state of disrepair and need changes to work efficiently with r134a. If you are willing to refurbish, replace and adjust some items and make the right changes/upgrades to the system, I've found it works very well. That's not to say a new aftermarket, under dash setup like Vintage Air wouldn't be a great system - I just think people underestimate the performance of the factory unit when it's update appropriately.

https://static1.pt-content.com/images/pt/2020/04/ly6swap1481-1.jpg

Here are some notes regarding what I did to get the system working properly:
(1) Replace the TXV with a new one set for R134a. The original TXV will under-deliver coolant and reduce the evaporator cooling capacity, because the superheat setpoint in the TXV is not appropriate for r134a. I replaced mine with 4Seasons 38622.
(2) Adjust the POA valve suction setting to around 26psia. The original POA setpoint will result in higher evaporator temperatures which will reduce the cooling effectiveness significantly. By adjusting this, the evaporator temperature can be brought back down to near freezing which maximizes heat transfer to the cabin air. I have videos on testing and readjusting the POA valve in videos linked below.
(3) Upgrade the condenser to a modern replacement. The original tube-and-fin condenser will not transfer enough heat to keep up with the evaporator when using r134a at higher ambient temperatures. Newer condensers are parallel flow which greatly improves cooling capacity. I used a Vintage Air condenser kit P/N 021171, but any modern universal condenser will work well provided you use one of the largest area available.

Other things that may or may not need to be done, depending on what you've got going on, include making appropriate lines to connect things, replacing the drier, flushing the evaporator, and using a compressor in good working condition. I used a Denso compressor that came factory in the newer Silverados. The factory system also may need repairs. You need to make sure the blower resistors are working as well as the high speed relay. You also need to make sure the switches on the control unit and ducting are working. And finally you need to make sure all the ducts and vacuum actuators & control valve are functioning. A factory service manual is really helpful for understanding how the system works and finding problems. My system current has a malfunctioning vacuum valve, so sometimes I get recirc air and sometimes not. Recirculation helps to get the lowest possible vent temperatures. Without recirc on a hot day my vent temps get down to around 42 driving around.

One major benefit of the factory system is you can bring in fresh air instead of using recirc air only. I definitely prefer that for general ventilation. Most of the time I don't need the AC running to feel comfortable in the car. Another benefit is that the system is very simple with no electronics whatsover. The drawbacks include a system with some 50yr old components, some of which are very difficult to refurbish or replace. I also think the blower capacity could be improved but I may just need to rebuild mine. Some advantages of a newer Vintage Air system (for example) include all new components, increase engine bay space & "cleanliness", and a warranty. You also wont have to figure out charge amounts or risk charging a system that may have issues now or down the line. I would say ease of installation is also an advantage over making the modifications and custom lines for the factory system, but I haven't installed VA myself so I'm not sure what you might run into.

Here are a couple of videos you may find helpful:
POA valve testing:
https://youtu.be/PhWW7hD9-Yw

POA valve adjustment:
https://youtu.be/B95_q7Z8DIE

Evaporator flush:
https://youtu.be/vMpsEwh7Uqg