Tim Huber, IDG Nashville, reports the story from Greg Hunter, Hunters Tractor & Equipment.
Mr. Hunter’s father purchased the R-17 used in 1957 and the serial number 18851 shows that this is a 1942 vintage vacuum pump. Mr. Hunter started using the R-17 as an air compressor in 1985 and continues to use it TODAY.
They were not sure what oil to put in it since the oil looked like 90 weight oil, so since 1985 they have only added oil to it and have not changed the oil. They operate the vacuum pump as an air compressor at 80 psig. The only service done to the R-17 is replacing a check valve in 1985 and a head gasket in 1985 and 2009.