Definition 1 of 2
Definition
In a magneto, the precise relationship between the position of the rotating magnet and the opening of the breaker points (or equivalent triggering device). When the magnet is in the position that produces maximum magnetic flux change (the E-gap position), the points must open to induce the highest possible voltage in the secondary coil for the spark plug.
Plain English
It is the timing inside the magneto itself — making sure the points open at exactly the right moment in the magnet's rotation so the magneto produces the strongest possible spark.
Context Anchor
Seen in aircraft engine ignition maintenance, especially when inspecting, overhauling, or installing magnetos.
Derivation
"Internal" because this timing happens inside the magneto, between its own moving parts. It is set and checked separately from external timing, which is the timing of the magneto to the engine's crankshaft.
Why Pilots Care
Proper internal timing prevents late or early ignition that can cause detonation, power loss, or engine damage.
Analogy
It is like setting the hands inside a clock correctly before hanging the clock on the wall. If the clock itself is wrong, placing it neatly on the wall will not make it show the right time.
Intuition Check
Do not confuse internal timing with timing the magneto to the engine. Internal timing is the setting inside the magneto; engine timing is how that magneto is positioned on the engine.
Example Sentence 1
After reassembling the magneto, the technician set the internal timing by aligning the rotor to the E-gap position and adjusting the points to just open.
Example Sentence 2
Once internal timing was complete, the magneto was installed and external timing was verified against the engine timing marks.