The Ford Barn

rotorwrench · 02-26-2025, 02:43 PM

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Coils aren't strictly made for any particular voltage. The can type coils were mostly 1.5 Ohm primary types. Ford used them in the model A era but Henry was keen to use a front mount distributor on the V8 engine since it was direct drive to the cam. I'm not sure how Henry Ford got to know Marion Mallory but it's known that they were friends. Mallory worked with the Ford electrical engineer to develop the front mounted distributor and the coils that attached to it. These coils were using the same principle as the can type coil but the shape and packaging made them different. Due to this difference, they found that a 0.8 Ohm ballast resistor controlled the heat well enough to give an acceptable spark and give good reliability to both the coil and the breaker assembly to include the condenser. It was efficient enough to give a good hot spark at the lower amperage.

The dual point breaker controlled the dwell and the vacuum brake gave a decent amount of load control. It was actually pretty ingenious the way it functioned and was very reliable in service. Henry was already passed on to the ages by the time the Holley Load-O-Matic system was developed in the 8BA era. The can type 1.5 Ohm coils functioned just fine with no ballast but their load control was just good enough for a stock motor. If you add compression or change carburetors then all bets are off.

02-26-2025, 02:43 PM	#6
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 17,410	Re: Ballast resistor Sponsored Links (Register now to hide all advertisements) Coils aren't strictly made for any particular voltage. The can type coils were mostly 1.5 Ohm primary types. Ford used them in the model A era but Henry was keen to use a front mount distributor on the V8 engine since it was direct drive to the cam. I'm not sure how Henry Ford got to know Marion Mallory but it's known that they were friends. Mallory worked with the Ford electrical engineer to develop the front mounted distributor and the coils that attached to it. These coils were using the same principle as the can type coil but the shape and packaging made them different. Due to this difference, they found that a 0.8 Ohm ballast resistor controlled the heat well enough to give an acceptable spark and give good reliability to both the coil and the breaker assembly to include the condenser. It was efficient enough to give a good hot spark at the lower amperage. The dual point breaker controlled the dwell and the vacuum brake gave a decent amount of load control. It was actually pretty ingenious the way it functioned and was very reliable in service. Henry was already passed on to the ages by the time the Holley Load-O-Matic system was developed in the 8BA era. The can type 1.5 Ohm coils functioned just fine with no ballast but their load control was just good enough for a stock motor. If you add compression or change carburetors then all bets are off.