Spark Knock in my '59

["Rex Crews" <rexcrews@xxxxxxxxxxxxx>]

Hi, Guys and Gals,

I would like some feedback on spark knocking or pinging on my '59.  I have
changed the points, checked, set and re-set the timing, and bought different
gasolines.  Still, I have a weird problem with spark knock on acceleration
and can even hear it at high speeds.  The odd symptom is, though, that the
problem is not consistent.  One day it doesn't ping at all, and the next day
it is terrible.  My mechanic thinks the distributor shaft is worn and is
shifting the timing, but the car has only 75,000 original miles.  Any
suggestions about the cause?  BTW, my 60 and 61 Imperials have zero spark
knock....  Thanks in advance.

Rex Crews  '59 and '60 Crowns, '61 Custom