if i had to take a guess, i would say you've been driving out of time for a while, and the cam and the crank gradually start slipping away from each other, did you crank the engine to number one cylinder to top dead center? that should at least line the smaller cog and then maybe try and crank the valves so that the pin fits with the two dots lined up correctly. I don't know for sure but this should at least get your post back up so someone with more knowledge can get a chance to look at it. i'm about to do the same to my 90 this weekend. let me know how it goes.