SPARK CONTROL

Manawatu Times, Volume LIV, Issue 6811, 15 January 1929, Page 4

SPARK CONTROL

Many drivers fail to pay any attention to their spark control levers, and then wonder why there is a bad knocking in the engine when the car .slows down on a hill. This knocking is what is known as a spark knock. When on a hill, a driver wishing to get all the power possible out of his engine, opens his throttle wide, with the result that the explosion is a very powerful one. The "engine, however, has slowed down considerably, and if the spark lever is advanced, it is probable that the spark will have come in tho cylinders and the gases have been fully ignited before the now slowly moving piston has reached top centre. The force of the explosion will therefore, try to make tho piston go backward, or, in other words, reverse the direction of revolution of the engine. The forward movement of the car and of the flywheel, however, will not permit this. Thus, there is a sort of struggle taking place between the two forces, and if there be any looseness in the engine, there will be a violent ingProm this we seo that when climbing a hill, as the car slows down, the spark should be slowly retarded, but should you shift to second, the. spark should immediately bo advanced again.