Automotive Air Conditioning Information Forum (Archives)

Positrack on Sat April 11, 2015 4:23 PM

Year: 1978
Make: Chevy
Model: K30 pickup
Engine Size: 400 SBC
Refrigerant Type: R12

I'm building a '78 Chevy K30 for work, trail, and camping use. It came as a non-A/C truck, and I have converted it to use the full factory A/C system. However, I'm really not very experienced with A/C and would greatly appreciate some guidance.

So far, I've rebuilt and installed the factory heater and A/C boxes from another truck (and installed a new heater core and evaporator). I also installed a new evap. temp switch (has capillary tube that wraps around the small evaporator line), supposedly for R12. I am now trying to decide what compressor to run, and I've read conflicting info about this. my options:
-I have a used factory A6 compressor from the donor truck that was converted to 134 and DID work, but the clutch failed (I may have overcharged it).
-new or rebuilt factory A6
-Sanden or another more common/modern compressor

I'm less concerned with cost than with getting it right the first time, long-term reliability, and getting the best performance possible out of the A/C system. I read some on Vintage Air's website, and they claim that the A6 is too large in displacement and the Sanden would be far better. On the other hand, I've read all over the 'net that the A6 is a fantastic powerhouse of a compressor worth keeping if you can stand the size and weight. It seems everyone agrees the rebuilt compressors are not good.

If it matters, I'm also planning on running a more modern parallel flow condenser, and this one matches the dimensions of the factory tube and fin unit perfectly:

http://www.summitracing.com/parts/vta-037030-ovr/overview/

Any thoughts there? Any other advice? Again, I'm willing to do some work and spend some money on this, but I want to do it right and get the best performance I can out of it. Though I have liberally covered the cab in Lizardskin and some other mat and foam insulation, the truck is going to run a bare bed-lined floor, and it gets hot and miserably humid here so I (well, more the wife and kid... ) need all the A/C performance I can get. Any advice would be greatly appreciated.

Edited: Sat April 11, 2015 at 8:58 PM by Positrack

TRB on Sun April 12, 2015 1:00 PM

Nothing really wrong with the A6 it just big and heavy. Swapping to a sanden style compressor will have added costs for the compressor mount. I prefer the Alpha over the Sanden but Sanden is a good option. Pretty pricey condenser, make you own mounting tabs and save $100.00 dollars.

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Positrack on Sun April 12, 2015 1:54 PM

Thanks for the reply! I'd be perfectly happy running the A6, but as I said, I've come across conflicting info on them. I'd also be willing to go with a more modern design if it would improve performance or reliability, but if the A6 is as good or better than anything else I could get, I might as well stick with it.

I'll have to research the Alpha - haven't run across that one yet.

Do you think I'd be better off buying new over rebuilt? Can the used compressor I have be tested to see if it's still good? If I ran the used one, I'd still need to put a clutch on it. What is the most reliable source for a new one?

As to the condenser, yeah, it's pricey, but it doesn't seem WAY out of line with the stock replacement tube/fin type they sell at the parts store. I think I was looking at somewhere around $140 for a stock replacement from O'Reilly's. I'd be perfectly happy building mounts; in fact, it looks like I'll have to modify that one to work, but I would like to run the more efficient parallel flow style since I'm starting from scratch. It may not be necessary, but a more efficient modern condenser couldn't be a bad thing, right? The VA unit in my post is the only one I could find that matched the stock dimensions (28.5"x16"). If anybody knows of any others, I'm all ears. Thanks again.

Edited: Sun April 12, 2015 at 1:55 PM by Positrack

TRB on Sun April 12, 2015 3:28 PM

New A6 and update the condenser is a good option.

http://www.ackits.com/painted-parallel-flow-condensers


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Positrack on Sun April 12, 2015 6:25 PM

Wow, that IS a difference. Thanks for the link! You guys don't sell new A6 compressors do you? By the prices, I'm guessing the ones you offer on the site are rebuilds?

TRB on Sun April 12, 2015 9:49 PM

New Single Groove A6.

http://www.ackits.com/comp-a6-1gr-5in-12v-200-metric-th-r134a-whps-2941?search=20-10406


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Positrack on Sun April 12, 2015 11:23 PM

That's great, thanks for your help. It says in the description "R134A," will it also work with R12? You don't happen to have the same new compressor with the same 5" (+-) pulley in SAE rather than Metric do you? Not a big deal, but if you sell them either way, I'd rather have standard threads.

I searched under my vehicle app., and I couldn't find a new one; thanks for pointing me in the right direction. Assuming it will work with R12, I'll be buying one. I appreciate the help.


Edited: Sun April 12, 2015 at 11:27 PM by Positrack

TRB on Sun April 12, 2015 11:46 PM

I'll check our supplies Monday.

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TRB on Mon April 13, 2015 12:01 PM

All the standard thread A6 compressors are remans.

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Positrack on Mon April 13, 2015 7:45 PM

I see it's listed for R134; will this compressor work with R12? What's the difference, the included oil?

TRB on Mon April 13, 2015 8:03 PM

Oil, swap the oil to mineral and you will be fine.

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