A/C Compressor & Superheat Switch

**Rolf Krueger** · July 28, 1999, 03:10 PM

Re: A/C Compressor &amp; Superheat Switch

1. The GM remanufactred A-6 air conditioning compressors are generic in that they will fit a wide range of applications. GM stopped stocking a remanufacured compressor with the superheat switch a long time ago because of limited demand.

2. Most, if not all, of the remanufactured A-6 compressors have the provision for the superheat switch on the rear plate of the compressor. It is capped off and the cap is retained by an internal C retainer.

3. The part number for the superheat switch is 9956790 or Delco DL 15-2110. You can get these from a GM or Delco dealer (Delco is cheaper). You can install the superheat switch fairly easily before installing the compressor on the car. I have done this a number of times without any problems.

4. The factory installed part number for the Thermal Fuse was 6556440. The service replacement part number is 6551258 or Delco DL 15-2109

**Rolf Krueger** · July 28, 1999, 03:10 PM

Re: A/C Compressor &amp; Superheat Switch

1. The GM remanufactred A-6 air conditioning compressors are generic in that they will fit a wide range of applications. GM stopped stocking a remanufacured compressor with the superheat switch a long time ago because of limited demand.

2. Most, if not all, of the remanufactured A-6 compressors have the provision for the superheat switch on the rear plate of the compressor. It is capped off and the cap is retained by an internal C retainer.

3. The part number for the superheat switch is 9956790 or Delco DL 15-2110. You can get these from a GM or Delco dealer (Delco is cheaper). You can install the superheat switch fairly easily before installing the compressor on the car. I have done this a number of times without any problems.

4. The factory installed part number for the Thermal Fuse was 6556440. The service replacement part number is 6551258 or Delco DL 15-2109

**Jim** · July 28, 1999, 04:03 PM

Re: A/C Compressor &amp; Superheat Switch

Thanks Rolf, you're the man. I guess that they just sent me one of the compressors without the provision. If I understand what you said correctly, the remanufactured compressors available today may or may not have the provision for the switch (I guess it depends on the core they used). I'll take this up with the dealer where I got it. Jim

**Jim** · July 28, 1999, 04:03 PM

Re: A/C Compressor &amp; Superheat Switch

Thanks Rolf, you're the man. I guess that they just sent me one of the compressors without the provision. If I understand what you said correctly, the remanufactured compressors available today may or may not have the provision for the switch (I guess it depends on the core they used). I'll take this up with the dealer where I got it. Jim

**Jack H.** · July 28, 1999, 08:22 PM

Re: A/C Compressor &amp; Superheat Switch

Could be part of what Rolf is saying is the difference between dealing with GM/Chevy and AC/United Delco. Just sent a local member yesterday for an A-6 for his '71 that wanted correct internal displacement, correct clocking of clutch coil (most passenger cars mounted on LH of engine vs. Corvette's RH requiring clutch assy to be removed and coil 'flipped' on the common variety A-6 rebuilds) and correct clutch pulley dimension (another commonly changed out item on many generic rebuilds) to the local AC/United Delco dealer. NO PROBLEMA! Had the item in stock....

**Jack H.** · July 28, 1999, 08:22 PM

Re: A/C Compressor &amp; Superheat Switch

Could be part of what Rolf is saying is the difference between dealing with GM/Chevy and AC/United Delco. Just sent a local member yesterday for an A-6 for his '71 that wanted correct internal displacement, correct clocking of clutch coil (most passenger cars mounted on LH of engine vs. Corvette's RH requiring clutch assy to be removed and coil 'flipped' on the common variety A-6 rebuilds) and correct clutch pulley dimension (another commonly changed out item on many generic rebuilds) to the local AC/United Delco dealer. NO PROBLEMA! Had the item in stock....

**Jim** · July 29, 1999, 07:46 AM

Re: A/C Compressor &amp; Superheat Switch

Jack, I must be shopping in the wrong place then. I'm not trying to bad-mouth them, but I've been dealing with The Last Detail in Georgia who is an AC-Delco distributor and let's just say it was an effort trying to find someone who even knows what a superheat switch is. This should not be this difficult. I think I'm just going to go to a local A/C-Delco dealer and do what the member local to you did. Does anybody have the part number for what I need ???

**Jim** · July 29, 1999, 07:46 AM

Re: A/C Compressor &amp; Superheat Switch

Jack, I must be shopping in the wrong place then. I'm not trying to bad-mouth them, but I've been dealing with The Last Detail in Georgia who is an AC-Delco distributor and let's just say it was an effort trying to find someone who even knows what a superheat switch is. This should not be this difficult. I think I'm just going to go to a local A/C-Delco dealer and do what the member local to you did. Does anybody have the part number for what I need ???

**Jack H.** · July 29, 1999, 11:01 AM

Re: A/C Compressor &amp; Superheat Switch

Hum, thought ole Rolf did an EXCELLENT job of feeding you details (including P/N's) for the items. Remember, the early A-6 without safety switch is a bona fida functional replacement for factory original as it will run/work without the switch....

To get the real McCoy compressor assy, you need P/N from AIM (1131002) and insist on that P/N for concours application. Guys in the business handle many market segments (keep it running to full concours) and sometimes they work to the lowest common denominator.

Last, there ARE folks out there who will custom rebuild an original A-6 to preserve it (label was dated). Getting harder to find these days as the big boys with their reverse assy lines make it uneconomic to compete. But, local Delco folks should be able to point you in the right direction as they're probably supplying the boutique rebuilder with parts....

**Jack H.** · July 29, 1999, 11:01 AM

Re: A/C Compressor &amp; Superheat Switch

Hum, thought ole Rolf did an EXCELLENT job of feeding you details (including P/N's) for the items. Remember, the early A-6 without safety switch is a bona fida functional replacement for factory original as it will run/work without the switch....

To get the real McCoy compressor assy, you need P/N from AIM (1131002) and insist on that P/N for concours application. Guys in the business handle many market segments (keep it running to full concours) and sometimes they work to the lowest common denominator.

Last, there ARE folks out there who will custom rebuild an original A-6 to preserve it (label was dated). Getting harder to find these days as the big boys with their reverse assy lines make it uneconomic to compete. But, local Delco folks should be able to point you in the right direction as they're probably supplying the boutique rebuilder with parts....

**Jim** · July 29, 1999, 11:30 AM

Re: A/C Compressor &amp; Superheat Switch

Thanks Jack (and Rolf). I think I'm getting too wrapped up in this for my own good. My whole thought processs is this; I'm just reluctant to give up the low pressure cut-out protection on the system when I really don't see any reason that I need to. It shouldn't be this difficult to get a compressor with the provision for a superheat switch.

Rolf, I mean no disrespect. Your info. was and is proving exceedingly valuable to me in my quest. Once again, thanks. Jim

**Jim** · July 29, 1999, 11:30 AM

Re: A/C Compressor &amp; Superheat Switch

Thanks Jack (and Rolf). I think I'm getting too wrapped up in this for my own good. My whole thought processs is this; I'm just reluctant to give up the low pressure cut-out protection on the system when I really don't see any reason that I need to. It shouldn't be this difficult to get a compressor with the provision for a superheat switch.

Rolf, I mean no disrespect. Your info. was and is proving exceedingly valuable to me in my quest. Once again, thanks. Jim

**Duke W.** · February 9, 2001, 12:10 PM

Re: A followup question

Even with the 151 cam you're still limited to about 6000 RPM. If your rods pass maganflux they are probably okay, but shotpeening them would be a good idea. Now by the time you add up the cost of resizing, new bolts, and shotpeening,you might be close to a set of Sportsmans. They are overkill for your application, but will make the engine pretty much bulletproof.

When I rebuilt by '63 SHP engine I had one very badly cracked rod. I replaced it with the latter small bearing rod with the raised hump next to the bolt seat. Then I had them all resized, ARP bolts, and shotpeened. Relatively inexpensive rods weren't available back then, but if I was doing it today, I would probably just buy a set of Sportsmans.

Duke

**Duke W.** · February 9, 2001, 12:14 PM

P.S.

I believe the Sportsmans are a bit heavier than the OEM rods. Whatever you do - rework the OEM rods or go with the Sportsmans - you should have the entire rotating and reciprocating bottom end balanced by a suitably qualified shop.

Duke

A/C Compressor & Superheat Switch