If theres a hole in the piston, your compression readings will be zero or extremely low, and your leakdown will be large.

Something is odd if it only runs at that timing, is it possible that the timing chain may have skipped a gear, or the cam timing was modified?

Pinging only happens when you have a lean mixture under load, or are using a low octane fuel that detonates easy. Raising the octane basically increases the fuels resistance to pinging, so 94 octane should lessen pinging (it has in my cars when I wanted to run more timing or boost).

Thats all I can think of now.