I think you have a bad check valve in that lifter. It may quiet down after the check valve wears in.
How many miles should I give it to wear in before replacing it?
Has the engine been rebuilt or are you using it as it came out of the car just with new gaskets etc? I had one back in the 70's when I was young and dumb just couldn't get rid of that tapping valve lifter. Couldn't seem to get rid of it buy replacing a lifter or adjustment. My father in law, an old time mechanic, ask me if I was tired of messing with it yet and I let him look at it. He said cracked piston around the wrist pin. I didn't believe him and pulled down found it as he said. Never doubted him again.
Larryw
It hasn't been rebuilt. Whats confusing me is that I can make the noise go away by tightening the valve adjustment. Which, in my mind anyhow, would seem to point to a valve or lifter issue. Between that and hearing a distinctly different noise when touching the valve spring on that lone valve makes me fairly confident it isn't something else making noise. That said, I am definitely going to keep that thought in the back of my mind. I could just be young and dumb.
