Working on a Scintilla magneto is a journey into a remarkable piece of engineering history. By understanding the principles, following careful procedures, and appreciating its heritage, you can keep these iconic devices producing their vital spark for generations to come.
The Scintilla magneto operates via three interconnected subsystems:
Regular servicing prevents internal carbon tracking and ensures reliable engine starting. Every 25 Operating Hours
Over-oiling is the leading cause of magneto failure. Use a specialized high-temperature cam grease on the breaker cam, but only a tiny, "matchhead-sized" amount. 4. Troubleshooting Common Issues Likely Cause Grounded "P-lead" or fouled points. Disconnect the kill switch wire to isolate the mag. Weak Spark Weak internal magnet or aged capacitor. Test magnet strength; replace the condenser/capacitor. Engine Kickback Timing too far advanced or impulse coupling sticking. Retime the mag to the engine; clean the impulse springs. Misfire at High RPM Points bouncing or worn cam lobe. Check point tension and cam wear. 5. Safety Warning: The "Hot" Magneto
: Maintaining these units was no small feat. A basic torque check on the points screws—often including removing the cowl, p-leads, and the magneto itself—could take a skilled mechanic 4 to 5 hours to complete correctly. Historical Context
Ensure the mechanical flyweights move freely without binding.
1. P-lead grounded permanently.2. Breaker points oxidized or oily.3. Defective coil (internal short).
Once restored, proper storage is key:
Breaking the circuit causes the magnetic field around the coil to collapse instantly.
Routes this high-voltage current to the correct spark plug wire via a rotating rotor arm. 3. Step-by-Step Internal Timing (E-Gap Alignment)
Used extensively in aircraft (like Pratt & Whitney R-2800) and high-performance automotive engines. 2. Key Information in a Scintilla Magneto Manual