How did you set it by ear?
-The best or highest idle?
-The most adv without pinging under load?

Most, if not all, motors will like a lot of advance at idle. Bad thing is it ends up with too much total when you drive it.
Setting it by ear usually means to adv the dist till it pings under hard accel, then back it off a bit.

Hope your motor repair will be an easy fix.