22re Ping/detonation Over Advanced Timing?

HAPPY XMAS ALL!
I've got a 88 runner/22RE. with 5btdc(short connect) im getting quite a detonation with accleration but not at idle. some say its just piston slap but the block only has 15k on it and if I bump initial timing to tdc, the terrible sound is gone.?? engine guy i know says ping/detonation can have a high pitch metallic tone and actually cause piston slap even if all clearances are to spec. anyone have similar experiences? input?
ryan J.

Sounds like detonation for sure. Doesn't have anything to do with piston slap - this is caused by too wide piston-wall clearance. The noise you hear is the piston/rod beating on the crank, and the head ringing from the way too high pressure caused by the detonation. Same effect as if you hit it with a hammer.

thanks brian, I have a much clearer picture of whats happening in my engine.!

You're welcome