PFF - Pennock's Fiero Forum, PDA Edition

Using A/C lines with 4.9 compressor (Page 1/1)

falcon_ca

AUG 23, 10:32 PM

One of my project next winter is to install A/C in my non A/C Formula with a 4.9 swap in it.

I have everything from the donnor 88 Fiero except for the compressor. Obviously, some parts will nee to be replaced such as the dryer and the orifice tube.

I will use the compressor form the 4.9.

I am aware of the the high pressure sensor needing to be installed on the Fiero's high pressure line.

I am just wondering why I can't use the Fiero compressor connector on the Cadillac compressor. It seems to fit. No ?

Dennis LaGrua

AUG 24, 09:51 AM

The Fiero A/C compressor fitting should fit the Cadillac compressor. IIRC, Ed Parks used the same compressor hose in his 4.9L swaps and bent it to fit. In the worse care you can install the old fittings on a new A/C hose with new crimp sleeves.

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Dennis LaGrua

AUG 24, 09:52 AM

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[This message has been edited by Dennis LaGrua (edited 08-24-2020).]

Raydar

AUG 24, 04:48 PM

The original 4.9 compressor had the holes in the back head filled in, but if you end up replacing the compressor, the replacement will likely have removable "blank plugs". You can install a high pressure switch in one of those positions, and wire it in.
(FWIW... The Fiero Factory installations did not include a high pressure switch at all. They depended upon the compressor to "vent" if the pressure got too high. I found that out when I was coming back from the 30th, and blew off the high pressure hose. Made a hell of a noise.

)

[This message has been edited by Raydar (edited 08-24-2020).]

falcon_ca

AUG 24, 05:32 PM

quote

Originally posted by Raydar:

The original 4.9 compressor had the holes in the back head filled in, but if you end up replacing the compressor, the replacement will likely have removable "blank plugs". You can install a high pressure switch in one of those positions, and wire it in.
(FWIW... The Fiero Factory installations did not include a high pressure switch at all. They depended upon the compressor to "vent" if the pressure got too high. I found that out when I was coming back from the 30th, and blew off the high pressure hose. Made a hell of a noise.

)

Yes , That is why I will install and external high pressure swith somewhere on the high pressuere hose

Thanks

Dennis LaGrua

AUG 24, 07:44 PM

The Delphi Compressor on my 4.9L does not have the hole for the high pressure switch. I don't believe that all the GM 4.9L Harrison compressors did as well. The solution is to add a high pressure switch on the high side line. I did this on my 3800SC system by aluminum brazing in a 10mm switch port on the aluminum line at the manifold connection at the firewall. While I do have respect for the Ed Parks 4.9L swaps and they were done well, this is one area where he could have done better