"Bob" wrote in message
...

My question is this...does altitude affect ignition timing?

If you have the old fashion mechanical distributor then no, altitude would
not change your timing. If you have a totally electronic computer
controlled fuel and ignition system then it would be possible.

It is far more likely that the reduction in the amount of ping is due to the
lower atmospheric pressure. The lower air pressure will have the same
result as if your engine had a lower compression ratio, which is what
requires the higher octane fuel to avoid pinging.

Rod