It seems nowadays most commercial air compressors available at the stores are a cheap induction motor spinning at 3600/3000RPM coupled to a compressor via direct drive - Noisy and possibly not long lasting.

My first attempt, some 7 years ago was to build a silent model with a hermetic freezer compressor. The thing has been running happily ever since, although the output contains oil (Fine for the garage tools, not so great to paint)

I'm thinking about upgrading the design with a Semi hermetic compressor. These have a sump with oil and I'm under the assumption dont rely on the oil circulated by the refrigerant for their lubrication, my question is: Do the valves on the head require some kind of lubrication, or am I good just ensuring the sump oil level is maintained?

The particular model I'll be using is a Prestcold PK10X0017P, 1450 RPM.

Many Thanks