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LenNH
03-25-2008 11:33:58
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Re: Cranking a F-20 in reply to Va Gasman, 03-23-2008 10:30:09
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Lots of people in the "old days" got their arms broken by spinning the crank (the engine would kick back while they were pushing down). If the spark was retarded AND the impulse was working right, you SHOULDN'T get a kick back, but the impulse COULD fail to engage and then she goes backward---all 55 inches per cylinder--almost as much as a whole four-cylinder engine on some small cars. The impulse is supposed to give you enough spark to make the engine start without spinning. What will make everything work right is to have good clean points, a good condenser, AND a strong magnet (they do get weak over time). The spark lever was originally intended for use with the heavy fuels (kerosene or distillate). They knocked easily. If the driver heard knocking, he retarded the spark until the knocking stopped. Some of the early models (10-20, I think, and 15-30 for sure) had a separate water tank that allowed enough water into the intake to stop the knocking. Before automatic spark-advance, cars had "spark levers," too. The Ford A had manual spark advance/retard until 1931, long after other
makers had gone to automatic. This lever was used for starting the engine (retard to protect the starter drive) and in case it began to knock under heavy load. The driver could adjust for best power depending on the engine speed, too. Fun, if you happen to like telling your engine what to do. I did. My father's '32 Chevvy truck had a spark control, also, but it was just a little knob like the throttle that you could pull out if you had to crank it. It wasn't meant to be used on the road, because by this time, Chevrolet had an automatic (centrifugal) spark advance. I always used this knob just to protect the starter. The Bendix drive had a spring that was easy to break if the engine kicked back. No spring, no starter.
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