FIAT 124 Spider
Engine Maintenance + Modification
67
Spark Plugs have electrodes suspended in the combustion chamber and are connected
to a cap on top of the distributor by wires. When the distributor releases the coil’s
energy it travels through the cap, into plug wires, and into the spark plugs. The resulting
spark ignites the fuel/air mixture in the combustion chamber.
Plug Wires are designed to contain the high energy of the coil and deliver it to the spark
plugs. They are the largest wires in the engine compartment and are quite obvious as
they run the top of the cylinder head.
Points are small electrical switches that open and close as the distributor rotates. When
the points are closed an electrical field builds up in the ignition coil. When they open the
field collapses, releasing energy into the spark plug.
A Condenser is a small (typically silver) barrel on the body of the distributor. It absorbs
misdirected (for lack of a better term) energy that runs from the coil back to the points
instead of to the spark plugs. Without a condenser the points will deteriorate quickly or
weld themselves together.
The Magnetic Pickup is the equivalent of points on the electronic ignitions installed in
the 1979-1985 Spider. Instead of the striking motion and inevitable wear associated with
points, a magnetic pickup literally “picks up” the increasing and decreasing magnetic
wave created by lobes in the distributor shaft. The energy from the coil is released by a
control module located on the coil itself.
The Control Module is located on the coil pack of the 1979-1985 Spider. It
electronically collapses the coil’s electrical field.
The Vacuum Module is a dashpot located on the side of the 1979-1985 Spider
distributor. A diaphragm inside the dashpot is connected to a shaft that pulls or pushes
the advance plate. The diaphragm is moved via vacuum pulse from the throttle body.
On fuel injected cars it is connected to a port located near the throttle on the air flow
meter side of the throttle plate. On carbureted Spiders the port is located just above the
throttle plates. In both cases when the throttle opens a drop in air pressure pulls on the
diaphragm which in turn moves the advance mechanism.
9.2 Ignition System Identification
All Spiders made prior to 1979 had breaker points. A single-point distributor will have a
coil mounted to one of the inner fenders and a single condenser on the distributor body.
It is the least complex of the Spider ignition systems. A dual-points distributor is similar
to the single-point but has two condensers on the body and two sets of points on the
interior. Some 1973-1978 Spiders have had the dual-points removed (replaced with a
single point internally) or the entire distributor replaced with the single-point model. The
single and dual point distributors can be identified externally; single-point distributors
have a single condenser and wire (blue/black) running off of the distributor. Dual-point
distributors have two wires (green and green/black). The coil for both units is a common
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