Quote:
Originally Posted by CWPASADENA
This may also sound strange coming from an Engineer but a Model A Ford is a simple car and I like to not make things all complicated.
If someone wants to try to optimize the operation of their Model A by constantly adjusting the spark, that is fine with me BUT I think he is missing the enjoyment and simplisity of driving a car that has been around for more then three quarters of a century.
A Model A is a very simple and straight forward machine, Lets keep it and its operation that way.
Chris
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I agree.
Simplicity is why many people are drawn to the Model A even today.
Controlling the timing manually is not some complicated science; it's basically just common sense. The best place for the timing is always just short of detonation.
If you hear any pings then you have the timing too advanced for the particular speed and load. Retard just enough to make the noise stop. At this point you will have the best power or peak cylinder pressure which occurs between 14 and 18 degrees after TDC on a normally aspirated engine.
I might add that anything that affects the temperature of the combustion chamber (even hot or cold weather) will affect the correct timing setting for a particular speed and load.
Heat increases as compared to cooler temperatures make the fuel mixture burn faster just like increases in turbulence and compression. This is why the timing sometimes has to be retarded when climbing a hill for example.
When climbing a hill the extra load put on the engine generates more heat which causes the flame to burn faster AUTOMATICALLY. If too much of the burn occurs too close or slightly before TDC the chambers get hot fast because the piston is harder to push down (in fact temporarily static for an instant and basically locked until the crankshaft rotates) or it is still coming up to the top. If the temperature is greater than what the octane will stand then here come the pings or knocks. Retarding the timing moves the best part of the burn beyond TDC and the piston is easier to push down so the heat becomes less and the knocks stop.
Simple.
Larry B.