i have a 93 civic lx. it has a non vtec d15b block. i cant seem to advance the ignition timing far enough. i have been told that the d15b is from japan. it has a pm3-6 head. i read on another forum that its supposed to have a pm9-3 head. does any one know what that head came on and if its a obd 0 head and if im trying to use the wrong distributor or something. any help would be appreciated thank you