denyo dps 90 rotary compressor

Hey mate, I have a 90 cfm compressor here that over pressurize to the point that it stalls and pushes oil out of the air filter. I know the safety valve is not working and I have replaced the pressure regulator. It worked fine for about 3 hours and did it again this time tearing the delivery valve diaphragm out of place. Just wondering if you have ever seen this before any advise would be great