"Ping" as in detonation...if you go too far on the timing, the engine will start to ping (sounds kinda like marbles in a soda can). You'll have to advance the timing and drive it, advance and drive it, etc. Once you go too far the engine will either lose some power or start pinging...it's basically a trial and error thing. If the engine is pinging already, you'll have to diagnose and fix that first before you start messing with the timing

*EDIT* You must be careful while doing this, extreme detonation can burn holes in pistons...

 

oh shetos!!!! well its not pinging at all at this moment..it was just leaking oil from the intake valley....or so i was told..and well from wat i can see it dose look like its coming from there.well thats the reason for the work im gona do to it..cap&rotor,sparkplugs and wires intake and valve covers gaskets...

 

Just be sure to mark the position of the rotor, or set the engine up to TDC before you pull the distributor out Add a distributor gasket (or o-ring, not sure what a 90 uses) to that list...