Timing help!!

Hi crackedback,it was all going so well,I had the manifold vac up, i could start off on a hill with little effort it sounded good,then i got out on the road and started going thru the gears and it started pinging!After that i shut the car off and turned the vac adv on the dist. clockwise 1/2 inch (2degrees?) and it bottomed out .What does that mean?Should i adjust it the orther way and try that.