Because the fiber or plastic block that follows the cam slowly wears down and the points themselves are prone to burning away, the distributor contact-breaker points require more frequent adjustment than most other systems in the engine. The engine’s performance will degrade as the setting changes, and starting may become difficult.
The cap on the most common type of distributor has been removed, revealing the rotor arm, points, and condenser. Before you set contact-breaker points, clean and smooth them with a contact file. Release the wires if they need to be ground or renewed (either by unclipping or unscrewing to allow them to be lifted out). To set the gap, make sure the assembly’s heels are resting against a cam lobe, loosen the retaining screw slightly, and use a screwdriver to move the fixed part while measuring the gap with a suitable feeler gauge.
Wipe out the distributor cap, clean any carbon from the brass contacts, and ensure that the sprung central brush is not stuck or worn down before replacing it.