When magnetos are internally timed, what are you checking?

When magnetos are internally timed, what are you checking?

• A. Breaker points opening time relative to the engine's RPM.
• B. Internally timing a magneto consists of adjusting the breaker points so they will open at the instant the rotating magnet is in its E-gap position, and the distributor rotor is in position to direct the high voltage to cylinder number one.
• C. Setting the distributor to align with cylinder four.
• D. Ensuring the ignition switch aligns with the battery.

Answer: (B)

Magnetos that are timed internally rely on the magneto’s own timing mechanism to determine when the breaker points open. When checking this, you’re confirming that the points interrupt at the exact moment the rotating magnet reaches the E-gap position and the distributor rotor is aligned to feed the spark to cylinder number one. That precise opening time ensures the high-voltage spark is produced at the correct crankshaft position for cylinder one. Context helps: in an internally timed magneto, timing isn’t set by external engine timing hardware. The E-gap position is a fixed reference point inside the magneto, and the rotor’s orientation directs the spark to the correct cylinder. If the points open too early or too late relative to the E-gap, the spark would fire at the wrong time, harming engine timing and performance. Why the other ideas don’t fit: aligning to a specific engine RPM or to cylinder four isn’t about the magneto’s internal timing reference. The ignition switch’s position is not what sets the magneto’s timing. The key check is the points opening at the E-gap with the rotor positioned to fire cylinder one.

Magnetos that are timed internally rely on the magneto’s own timing mechanism to determine when the breaker points open. When checking this, you’re confirming that the points interrupt at the exact moment the rotating magnet reaches the E-gap position and the distributor rotor is aligned to feed the spark to cylinder number one. That precise opening time ensures the high-voltage spark is produced at the correct crankshaft position for cylinder one.

Context helps: in an internally timed magneto, timing isn’t set by external engine timing hardware. The E-gap position is a fixed reference point inside the magneto, and the rotor’s orientation directs the spark to the correct cylinder. If the points open too early or too late relative to the E-gap, the spark would fire at the wrong time, harming engine timing and performance.

Why the other ideas don’t fit: aligning to a specific engine RPM or to cylinder four isn’t about the magneto’s internal timing reference. The ignition switch’s position is not what sets the magneto’s timing. The key check is the points opening at the E-gap with the rotor positioned to fire cylinder one.