Interstage relief valve pops on high pressure side of Champion
(Wake Forest, NC)
Champion 2 stage air compressor
I have a older Champion 2 stage 175psi max 80 gallon air compressor.
On start up the pressure will build to about 50 psi and then the relief valve on the high pressure side starts releasing.
Noticed that someone had installed 200psi interstage relief valves, I guess to over come the issue instead of trying to fix the real problem.
I since replaced the relief valve with the correct psi of 75.
Now back to the original issue, what would be the most likely cause of the high pressure relief to pop at 50psi?
What specific type of oil for older Champion air compressor?
First off, I'm working with a standup 80 gal champion air compressor circa 1957. Has worked perfectly until lately. I noticed the oil getting a little discolored so I drained it and replaced it with SAE 30. Now, every time it kicks on, it smokes a little bit and now it's starting to smell. I'm kinda curious if today's standard of compressor oil is different than back then and it's too thin? Should I drain it and use an automotive 30 weight? If not, are there any ideas as to why it's acting up?