Located at the hear of Saturn's ignition system is the Saturn ignition coil. This coil is
basically a transformer that takes the relatively low voltage (12 volts) available from
the vehicle's battery and boosts it to a degree where it will fire up the spark plug as
much as 40,000 volts. There are actually two coils of wire looped around an iron core.
Saturn ignition coils are insulated from each other and the whole assembly is
capsulated in an oil-filled case. The primary Saturn ignition coil, comprised of
relatively few turns of a heavy wire, is linked to the two primary terminals located on
top of the coil. On the other hand, the secondary coil consists of many turns of fine
wires. It is attached to the high-tension connection on top of the coil.
Operationally, the battery's power is fed through a resistor or resistance wire to the
coil's primary circuit. It is then grounded through the sealed ignition points in the
distributor. "Powering" the Saturn ignition coil's primary circuit with battery voltage
produces current flow through the primary windings. In turn, this induces a very huge
and intense magnetic field. This magnetic field remains as long as current moves
around and the points remain sealed.
When the distributor cam rotates, the points are forced apart, breaking the primary
circuit and halting the current flow. Disrupting the flow of primary current results to
the magnetic field's collapse. As the current that flows through a wire creates a
magnetic field, moving a magnetic field across a wire will produce a current. As the
magnetic field collapses, its lines of force cross the secondary windings, producing a
current in them. With the secondary windings containing many wire turns, the voltage
from the primary windings is amplified considerably up to 40,000 volts.
The voltage from the Saturn ignition coil secondary windings flows through the coil
high-tension lead to the center of the distributor cap, where it is distributed by the
rotor to one of the outer terminals in the cap. From there, it flows through the spark
plug lead to the spark plug. This activity occurs in just a period of a split second and
is repeated every time the points open and shut, which is up to 1500 times a minute in
a 4-cylinder engine at stationary condition.
On Saturn vehicles, there is an individual Saturn ignition coil for each cylinder
mounted directly on top of the spark plug. This design gets rid of the high tension
spark plug wires for better reliability. Most of these systems use spark plugs that are
designed to last over 100,000 miles, which cuts down on maintenance costs.