i don't believe that the connections to the ignition coil should be reversed
when changing from positive earth to negative earth. ignition coils are not
polarity sensitive devices. the ignition system in a car works by interrupting
the flow of current through the coil by opening the points, setting up a
resonant circuit with the capacitor ( condenser). it is this oscillating
current transfering energy between the coil low tension (12volt) winding and
the capacitor that induces a voltage in the high tension winding of the coil (
the bit that connects to the spark plugs via the distributor). the resulting
voltage that fires the plugs is not D.C. as shown in some car manuals but is in
fact a short burst of radio frequency energy.
the point of all this is that the coil doesn't care which way the current flows
through it, only that the points interupt the current and that there is a
healthy capacitor ( condenser) with which to resonate.
changing the coil connections radically alters the circuit. it will still run
but with less spark. the fact that some coils are marked with '+' and '-'
terminals is misleading the + connection always goes to the ignition switch (
or 'hot wire') and the - minus always goes to the points regardles of battery
polarity.
happy negative earthing.
derek evans
south oz
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