Rockers?

[elev8_dude]

This has been an ongoing problem. I set my valves and the engines hums. With about two weeks of driving (regular), the car goes back to sounding like a diesel truck. My mechanic says my rockers are worn out. It used to do this prior to getting new valves, which I have now. But even with the new valves within 2 weeks maybe 3 they start knocking and get progressively worse.

So here I am, looking for a second opinion before I have to spend $$ again.

Any thoughts.