Checked LOGSA, found some -20P manuals, but they were only external serviceable parts, inlet filter, drive pulley, seal, bottom plate, nothing on the insides. I looked for info on the MS51322-1, 7.25 CFM, 1209 series compressor, the twin cylinder, air cooled one.
Just in case, here's some #s,
TM9-2320-211-20P
TM9-2320-209-20P
Maybe someone smarter than me can lend a helping hand.