Hi there,

In my stable are two 89s, a 90, and two 91s. There's definitely a great deal of difference between 90 and 91 - the txv system vs the orifice tube GM type. I hadn't thought about grabbing the components from a 91 to retrofit, although I have installed the Volvo kit in a 90 which includes the evaporator.

Here are a couple of pics I recently posted to show how the 91+ ac components make it a rougher job to change the Crank Position Sensor (CPS) at the top of the bell housing.

You can see the 91+ AC components literally take away the elbow room to work behind the head. What is not so obvious, is when the hard aluminum piping needs to be moved to replace the heater core on the other side of the firewall, this later GM system becomes a liability, unless of course, you can get it recovered and refilled.

But the advantages for cooling can tip the scales - it is so much easier to convert to R134, and, with the 91+ condenser fan, has a chance of being successful.

I don't know that the compressor or AC bracket has changed 90-91, in fact I rather doubt it, but I believe the hoses and piping are indeed specific to each one, judging by my memory from Monday, attempting to connect a gauge at the compressor test port before remembering the one by the accumulator.

It does still look like a project. And I am fairly sure the hard-line connected evap is a longer and round-ended shape that will not fit in the pre-91 heater box. Surely there are many on this board much more concerned, and knowledgeable, on the subject of 240 air conditioning, especially those living in Florida, who could fill in the details for you.






--
Art Benstein near Baltimore

To err is human, to moo bovine.