16-05-2021, 12:07 AM
A butt joint inside a plug could show infinite resitance but be of no consequence to the spark. Pugs which incorporate a radio resistor read quite high ohms. Not always satisfactory on simple coil ign systems.
Incidentally very wide gaps as moderns only necessary with weak mixtures, this undesirable on Sevens as need all power and to minimise valve recession. A normal mixture is fired by a very small gap as the magneto cars. The wWsp engin as DC3 ran .012 inch.
When running my Seven everyday and very familiar with its characteristics, I convinced myself that wider gaps had the same effect as slight spark advance.
Incidentally very wide gaps as moderns only necessary with weak mixtures, this undesirable on Sevens as need all power and to minimise valve recession. A normal mixture is fired by a very small gap as the magneto cars. The wWsp engin as DC3 ran .012 inch.
When running my Seven everyday and very familiar with its characteristics, I convinced myself that wider gaps had the same effect as slight spark advance.