This is probably a stupid question, but what does "pinging" sound like? I have never heard it before. I am advancing my timing, w/o a timing light, so its just trial and error. Thanks guys.
It sounds like a high pitched metallic noise to me. Most compare it to marbles rattling in a glass jar.
If you hear that, back the timing down a smidge at a time till it goes away. Since you dont have a timing light, be sure to make your adjustment, but then hold the dizzy cap (safely if you are doing this with the car running. You can/should make this adjustment with the car off since you are not using a timing light). But hold the dizzy while you tighten the hold-down bolt, as the final tightening can turn the dizzy a couple degrees (this can make you nuts real fast. ).