scroll type R4 compressor replacement(GM cars,76-95)

[cfz2882]

on one of the automotive forums i am on,there is discussion of a new scroll type compressor to replace original GM R4 piston type compressor used in a lot of 76-95 carsrobably made in china,these aftermarket compressors look very similar to original GM version.some users of this scroll design note AC performance at idle seems subpar compaired to original R4. Earlier R4 compressors were known to be craptastic,but possibly was improved later in its life these things generated a lot of aluminum dust that would mix in the oil and foul the shaft seal causing it to leak,oil slinging off the clutch and pulley.The large o-rings for the outer sleeve would leak in cold weather too once they were a few years old.

 

[vacerator]

I'm sure

they're all about the same anymore, same as residential units. R134a not R12. I don't know if the expansion valve orfice in the evaporator input needs changing.
The R4 began production with the downsized full and mid size cars in '77, and '78. A radial design, not axial. They had pressure cut off switches to save fuel.
They made ice cold A/C, same as the former Frigidaire axial unit. The external thermal limiter fuse was no longer needed. Those popped often anyway.
Sometime in the mid 80's, fron drive cars got a new type similar to todays.