Most of us just buy new parts periodically, but
Danny Rearden says, "High tension ignition components such as distributor
caps and rotors are generally only faulty if they are cracked, or have
carbon tracks on the surface. Even both of these conditions are usually
repairable if you are prepared to invest a few hours. My dad specialized in
repairing obsolete vintage and racing ignition systems and magnetos where
parts were completely unobtainable...