22re Ping/detonation Over Advanced Timing?

[Ryan J.]

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.

[Brian R.]

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.

[Ryan J.]

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

[Brian R.]

You're welcome