Subject: Engine Pinging

Over the last several weeks I've noticed that my Eldo is pinging when I
roll on some throttle.I don't think my driving habits hsve chsnged sny.
I put in new points and checked the timing and advance with a strobe.
All seems fine. I'm using the same high octane gas as usual. Could the
timing advance springs need changing? Could this be carbon build
up?..... Vince in NY