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TOPIC: Upgrade 1979 928 A/C Compressor to 2nd Gen 1980 and newer

Upgrade 1979 928 A/C Compressor to 2nd Gen 1980 and newer 20 Jun 2020 10:17 #21319


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My 1979 Porsche 928 air conditioning was leaking refrigerant from the hoses and compressor front seal. It was time for a major repair. The original generation compressor was only used from 1978 to 1979 production years. Parts are hard to find if available.

I had previously replaced the air conditioning compressor and hoses on my 1987 928 S4 and kept the old compressor. My idea was to upgrade my 1979 to use the 2nd generation and much more widely available compressor. I also used R134A refrigerant. This story outlines how to perform such an upgrade.

Thanks go to Dan Warner, owner of Exotic Motorwerks in Scottsdale Arizona (www.exoticmotorwerks.com) for making this idea a reality by specifying the parts & procedure, sourcing the used parts and performing the installation. Dan is an expert and makes these special projects happen.

The only new/rebuilt parts needed for this upgrade are:
  • A/C Compressor (2nd generation)
  • Desiccator bottle (receiver/dryer)
  • A/C Compressor Lines (comes with O-rings)
  • Desiccator bottle O-Ring
  • Misc O-rings for any other fittings

DSC06550LUpgradeparts.jpg


Dan is a perfectionist. Even though these are used parts, he had them replated to look like new.

The second generation Nippon Denso air conditioning compressors are widely available and are a good choice for this upgrade.

The used parts should be widely available as there are many early 1980s 928 parts cars and companies like 928 International stock used parts.

These are the new parts required:

AChosesanddessicant.jpg


NewPartsrequired.jpg


The choice of these new model year 1980 parts enables the existing 1979 Porsche 928 condenser to be used.

The compressor mounting hardware listed below should be available as used parts.

Compressormounting.jpg


UsedPartslist.jpg


PressureValvediagram.jpg


CompressorSuctionPressureValves.jpg


The items 4 & 5 (pressure & suction valves) are not included with a rebuilt compressor. They may be the most difficult items to source used. New parts are quite expensive so take your time to source these prior to starting the project.

The proof of success: On my drive home, the outside temperature was 100F / 38C. At top fan speed while driving at freeway speeds, the center vent output air temperature was a bit below 40F / 4C … I was smiling!
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Rich
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Last Edit: 20 Jun 2020 10:22 by Rich928.
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Upgrade 1979 928 A/C Compressor to 2nd Gen 1980 and newer 20 Jun 2020 13:20 #21322


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Thanks for doing the leg work, Rich! This might be in the future for my 79 as well!
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Upgrade 1979 928 A/C Compressor to 2nd Gen 1980 and newer 20 Jun 2020 13:46 #21323


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I have a PDF document with a bit more detail that outlines this information. Send me a note at 928ocmembership @ earthlink.net (remove the spaces in the email address) and I'll send it.
Rich
Membership Chairman
Charter Member
1993 928 GTS Cover Girl
1987 928 S4
1979 928 5-speed rescue
1979 928 5-liter track beast
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