Automotive Air Conditioning Information Forum (Archives)

Vetteman61 on Tue July 29, 2014 12:15 AM

Year: '71
Make: Pontiac
Model: Grand Safari

Hey guys,

I've been reading a whole bunch on the site in the last week. Despite the amount I've read I still am not confident about what to do in some areas of my 134 conversion (1971 Pontiac full size station wagon based on a Grand Ville/Bonneville/Catalina). It has a POA system. A/C systems are entirely new to me so the information is a bit overwhelming with so many different systems. I have read through my shop manual to attempt to understand the original components to the best of my ability. I was wondering if some of you guys could help fill in the gaps.

What I know and have done so far:
-I have a new evaporator core.
-I am going to fit a large, universal parallel flow condenser in place of the original finned condenser. The things I'll be looking at here are size and making sure the hook ups are near the same location as the original (same side of car). The mounting will take some modification but I am OK to handle that.
-I am going to test the original POA valve and reset it to the correct psi for 134a via the guide on this website
-I am going to use a Pro6Ten compressor to fit in the original mounts, which maintains as close to the same BTU output as an A6 compressor without the problems of oil slinging and bad rebuilds which are prone to happen these days
-I will get a 134a o-ring kit to replace my originals


What I don't understand:
-Can I simply bypass the muffler? To do this would I just make the new hose longer and leave it off completely?
-I understand I need a pressure cut-off switch since my system will not be cycling. How and where to I install this in my system?
-The Pro6Ten website offers two part numbers, one for Superheat and one for high pressure. I'm still not quite sure I understand which one I need. I understand one can replace the other, but I'm not sure what is involved here. If I add a pressure-cut off switch, would I still need either one?
-I don't exactly understand how my new hoses will need to run since I am changing the system. Right now it has clamps on the hoses but I have read that I need to convert to a crimped set of hoses. I know someone that can do the crimping, but I'm not sure how to go about getting fittings and things. I assume (perhaps wrongly) that there are universal sets of different turns and shapes for the metal parts of the hoses.

I don't see many pictures on this site. I get my car back tomorrow and I can take pictures, if they are acceptable on this site, of my setup after I have installed the new condenser and compressor. I believe I have a general understanding of what to install, I'm just not exactly sure how I need to connect it all back together since it will be different than what I have taken out.

Thanks,

Vetteman61 on Fri August 01, 2014 6:24 PM

Anyone?

94RX-7 on Sun August 03, 2014 1:50 PM

You need a high pressure cutoff (HPCO) switch installed somewhere on the high side of the system, preferably as close to the compressor as possible.

Ask the vendor of the compressor you're looking at if the HPCO will suffice for both types of switch. I suspect the answer is yes.

A good shop should be able to take your factory hoses, weld on some crimp type ends and crimp new rubber on. If the factory stuff won't work, you can get all sorts of A/C hose ends in various shapes and sizes to crimp onto various sizes of hose.

Muffler....no clue on that one.

Vetteman61 on Sun August 03, 2014 5:27 PM

Ok, thank you for the response.