1970 AC parts interchangeability

[Steve G.]

Hello,
I am looking for info regarding ac parts in engine compartment for big block car. I found someone with parts from a '68 and am wondering if anyone knows if the following parts are correct and interchangeable from a 68 to 70: condenser, dryer, AC lines (including muffler line), AC box, compressor, pulley, and brackets. If 'correct', which of these parts are date coded and where would I look for date code? The seller has other AC boxes from 68 - 72 cars, but doesn't know which boxes came from which cars. He says the POA and expansion valves look the same on all of them. But there are some minor differences from one box to another - he mentioned the clamps as one area. Anyone know what the differences are? I have included some pictures of the parts for reference.

Last question - there is a shroud that protects the lines inside the right front wheel well. It is fibreglass. Anyone know if that available NOS, used, or repro?

thanks, Steve

[Steve G.]

Re: 1970 AC parts interchangeability

More photo's of the parts...

[Terry M.]

Re: 1970 AC parts interchangeability

I am skeptical that system is from a 1968 Corvette. The vendor is right that 1968 AC system has worm type clamps at some of the junctions between the rubber line and the aluminum pipe. This system is all crimped and is more appropriate for your 1970.

Well this paint program at work will not let me downsize these images so I can post them. I'll ship the images home and try late tonight from there.

If this electronic magic works, there will be two images with red circles on them posted below. All three circles are the location of date codes. In the case of the expansion valve there may or may not be a stamped code. For the expansion valve and the hose at the core support the code will be Julian date followed by a single digit for the year -- at least I think that is the sequence, working from memory without an AC system in front of me.

The compressor will have a label on it with a model # and code # impressed on it. The model # will be for a 1970 big block -- look it up in the TIM&JG -- I don't have one here at work. The code # on the label is the date and shift of the compressor manufacture. That sequence is in the TIM&JG as well, and I don't have it in my head. Look it up.

[Dick W.]

Re: 1970 AC parts interchangeability

The hoses in the photos are not OEM GM. They are either aftermarket, or a set that someone has had made at a parts house. The original crimps reduced the whole sleeve evenly whereas the ones pictured has multiple crimps

[Dick W.]

Re: 1970 AC parts interchangeability

Another point that I forgot is that the evaporator core is unique to the '68. I cannot tell you what the difference between it and the '69-'72. I believe that you should look at a '68 for comparison. I also believe that the A/C housing is different.

[Steve G.]

Re: 1970 AC parts interchangeability

Thanks for inputs. So I assume the ac box looks correct for my 70 LS5, right? And the ac lines / muffler looks correct, except the hoses were changed. Does anyone know where I can find ac box, lines / muffler, compressor and / or any other ac parts that are definately correct for my car? Steve

[Terry M.]

Re: 1970 AC parts interchangeability

Well this paint program at work will not let me downsize these images so I can post them. I'll ship the images home and try late tonight from there.

If this electronic magic works, there will be two images with red circles on them posted below. All three circles are the location of date codes. In the case of the expansion valve there may or may not be a stamped code. For the expansion valve and the hose at the core support the code will be Julian date followed by a single digit for the year -- at least I think that is the sequence, working from memory without an AC system in front of me.

The compressor will have a label on it with a model # and code # impressed on it. The model # will be for a 1970 big block -- look it up in the TIM&JG -- I don't have one here at work. The code # on the label is the date and shift of the compressor manufacture. That sequence is in the TIM&JG as well, and I don't have it in my head. Look it up.

Sorry I had to work late last night and just couldn't get my stuff together to struggle with these image size issues. Let's see if I can do better today.

Nope, no better I resized the pictures to 448 x 336 and the image manager still told me they were too large. I give up.

Steve why don't you tell us what you are trying to accomplish?

[Steve G.]

Re: 1970 AC parts interchangeability

Thanks for trying Terry. My car was missing most of the ac components in the engine compartment when I bought it. Even the ac box got hacked up a bit. I am trying to find and install correct parts. I found these parts and was wondering if they would be correct or not for my car. If I am understanding this correctly, it sounds like 68 parts are different than 70. Though these parts don't look like they are from 68, so they may be correct. And, the parts that are date coded are: compressor, expansion valve, and hose that attaches to expansion valve. Did I get that correctly?

I am looking for all the ac parts in engine compartment. If anyone has a lead on these parts, including the ac box, I would be interested. I currently have the motor out, so replacing mine with a complete one would be easy to do now. thanks, Steve

[Terry M.]

Re: 1970 AC parts interchangeability

Steve, I am not so sure the parts themselves are that different -- at least external appearance from 1968 to 1972. I don't think they are. Obviously the manner of hose attachment is, and as Dick points out these are not original style crimps anyway. That almost makes me think the seller put together parts from various years to make one system. That may not all be bad as 30+ year old hoses aren't much good unless you are intending to just display the AC in your car. If you intend that it function, new hoses will be an advantage.

You have the dated components more or less right. The hose date is forward near the core support and is stamped into the crimp of the top most hose. Some expansion valves are dated. I am not sure that all of them were, but I have seen some with dates. I just haven't spent enough time with various AC parts to be able to say for sure. The compressor is dated on the label. there is another thread on this board asking about those details. Check it out.

PM me your email address and I will send you the photos with the Paint additions for where the dates are.