Finally its alive!!!

Congrats! That is very cool. It is very nice when it all comes together.

If you put it at 0 the spark starts to burn but it takes a micro second to light the A/F in the champer. buy that time the piston is down a little in the hole. So to get it to light off at TDC you need to light the plug a little befor top dead center to give the A/F time to burn all the way.

Don't know if that helped you any but some of the tech guys will chime in and give you a better example.

Good luck and have fun.