In a conventional ignition system, when is the spark timed correctly?

In a conventional ignition system, the timing of the spark is largely dependent on the opening of the breaker points. When the breaker points open at the correct moment in relation to the position of the piston in the cylinder, it allows the electrical current to flow through the ignition coil, generating a high-voltage spark at the spark plug. This spark needs to occur at the right time to ensure that it ignites the air-fuel mixture efficiently and effectively, which is crucial for optimal engine performance.

The moment when the points open, typically just before the piston reaches the top of its compression stroke, dictates when the spark will happen. If the points open too early or too late, the combustion process may not occur at the optimal point in the engine cycle, leading to reduced performance, increased emissions, or engine knock. Adjusting other components like the spark plug gap, armature air gap, or connecting the condenser with the breaker points may be important for the overall functioning of the ignition system, but it is the timing of the breaker points that directly ensures the spark happens when it should.