rpk55

All: Finally got the 88 3.2 back from the engine builder. The top end rebuild turned out great. I was able to help with some of the detailing, bead blasting and painting. And it's running really well. Now on to getting the AC working. The car has all barrier hoses installed about 3,000 miles ago along with a new rec/drier. The AC clutch crapped out the first time I turned it on. So, rather than replace the clutch I figured just put a new Denso with a clutch. All good, right?
Since the car had been converted to r134 and PAG with the new hoses, PAG is the way to go. However, Denso sends the compressors with Mineral Oil, or Ester already installed. I called Denso and they do not have a recommendation for the ration of PAG to Mineral oil to start the new compressor and Rec/drier with. The Bentley only has specs for mineral oil. Searching the Googleverse brings nothing trustworthy .
Any input, as always, will be appreciated. My AC helper is very good for the evac/fill/leak detections, etc. But I he is not an air cooled specialist and I don't want to burden him with this kind of stuff. Or maybe I'm over thinking?
Have a great Memorial Day weekend, and whatever is celebrated up North!
Rob

paranoidandroid

Overthinking it. The AC system is not much different than any other car, other than its chopped up (multiple condensers mainly) and way too many lines due to space.

The oil in your denso is there for shipping. Drain the oil completely from the compressor. You should probably get 2-3oz. You will need to rotate the compressor pulley to get all the oil out. It should turn freely without binding. If you see metal bits in the drained oil, stop and replace compressor.
Replace with the same amount of PAG in the compressor only - and no more than 3oz. If you add more, the compressor can lock up upon startup.

If you are unsure how much oil is in the hoses and other components, evac that out as well. In total, you should only have 8-10oz of oil in the total system. Any more than that you are losing efficiency with heat transfer or worse, you can lock up the compressor.

P.S. Your engine looks great. Also, if the drier was exposed to atmosphere, you probably need to replace it again.

rpk55

Android: Thanks for the well stated reply. I do have a new rec/dryer ready to install. I shouldn't find ant metal bits in the compressor oil as it just came from Denso, but I'll check anyway. 8-10 total is what I'll share with the person who will be handling the refrigerant part for me. Just the info I was looking for!