The use of motor oil is not recommended since it might contain some sort of detergents which may be beneficial for combustion engine but can be harmful for air compressor. Instead, use air compressor oil.
The California air tools are known to be quite. I have heard some very good reviews about California Air Tools CAT-1P1060S and California Air Tools 8010.
Hi pretty late to the thread but the use of motor oil is not recommended since it might contain some sort of detergents which may be beneficial for combustion engine but can be harmful for air compressor. Instead, you need to use air compressor oil.