08-04-2022, 08:03 PM
Large gaps, with a system to support, are beneficial with weak mixtures but in search of power and to avoid seat recession most Sevens are not run weak.
As before the plug gap for giant Double Wasp 18 cyl aero engines is .012".
When I used to drive my car every day in regular traffic I was convinced the engine was more smooth with small gaps. I suspect a large spark gets the burning underway more rapidly and gives a slight effective advance.
Large gaps raise voltage and compund any insulation weaknesses. Must not be used with delicate magnetos.
Decades ago there was an oft repeated advert where an engine was run with normal igniton and elctronic ignition and wide gaps and certifiably tested. There was a power gain. But the ign specs were unusually retarded. and not optimised for each.
As before the plug gap for giant Double Wasp 18 cyl aero engines is .012".
When I used to drive my car every day in regular traffic I was convinced the engine was more smooth with small gaps. I suspect a large spark gets the burning underway more rapidly and gives a slight effective advance.
Large gaps raise voltage and compund any insulation weaknesses. Must not be used with delicate magnetos.
Decades ago there was an oft repeated advert where an engine was run with normal igniton and elctronic ignition and wide gaps and certifiably tested. There was a power gain. But the ign specs were unusually retarded. and not optimised for each.