[Shogun]

Based on what I have seen from the new pics. I can only guess at what could be the cause of the problem. The pic at the top, the left rocker has scars near the base which might indicate an overtightened rocker during assembly of the engine thus leading to failure of the lifter which supports it. Why there is such a wierd wear pattern of both rockers is unknown, but still suggests to me it is not a rounded cam lobe unless you are using a non-synthetic oil which might cause pre-mature failure of said cam lobe. Because this is isolated to one cylinder, I believe the problem lies with the lifters, hense the tapping sound you hear after replacement of the worn rockers. In my experince, roller rockers are inhearently noisely anyway because of the many moving parts. There definantly is a problem if there is too much noise. my .02