I'm assuming carburator fuel injection mo at walang EFI, simple lang yan... nung makita ko gawin ng mekaniko, loosen the distributor holding screw (or clip... di ko na matandaan), run the engine, markahan mo yung original position ng distributor by making scratch marks using a flat head screw driver para kung gusto mo ibalik sa dating timing, you have a reference mark to guide you. then, veeerry slowly, turn the carburator either clockwise or counterclockwise, depende sa ikot nung contactor sa loob ng distributor. kung gusto mo i-advance, turn it opposite the direction of turn of the contactor, and vice versa... mararamdaman mo din naman yung engine mo kung tumutulin or bumabagal yung rebolusyon nya. Now, as how far you can advance the engine timing, yan ang di ko alam pano i-determine dahil depende yan sa model ng kotse mo. usually, gusto mo advanced. pero may danger pag sobra advanced, worst case yata is pwede mabaluktot piston rods mo, kasi parating pa lang ng TDC (top dead center) yung piston mo, nag-iignite na agad yung air/fuel combo sa loob ng cylinder. yun pagkaintindi ko pag sobra advanced. tsaka alam ko, medyo hirap din starting pag sobra advanced (at sobra delayed). hth.... baka matulong din yung ibang gurus ..intay mo lang sila.