RE: Old new car question,please see what you think
Pinging is the air/fuel mixture igniting OUTSIDEof the flame front, meaning not where/when optimum combustion happens in the cylinder. It's typically caused by a hot spot in the cylinder, which can often be caused by too much timing advance. Timing only affects cylinder pressure, not compression. Compression is a function of mechanical variables, like piston design, cylinder head design, head gasket thickness, etc. Cylinder pressure can be affected by timing, air/fuel ratio, engine rpm, etc. Compression is determined by the difference in cylinder volume when the piston is at the bottom of its stroke, to the top of its stroke.