1. Cam
It is a part of a distributor that is attached to the distributor shaft and rotates with it. It consists of lobes to open the contact breaker point. The number of lobes in the distributor is similar to the number of cylinders.
When the cam rotates, it drives the cam, follower and the breaker points are separated causing the current to break.
2. Capacitor
It also has a capacitor to protect the contact point of the contact breaker from overheating. It improves the output of high voltage current by reversing the current flow through the primary coil.
3. Condensor
Each ignition distributor is provided with a condenser at the contact points to reduce sparks as they open into the distributor thus minimizing burns and pitting of the points. Arcing occurs due to the effect of self-induction in the coil as the points block the flow of current.
4. Contact Breaker
The contact breaker is a mechanical designed breaker point. One end of the contact breaker is movable and the other one is fixed. Its function is to create and break the primary circuit current and is connected to the breaker assembly.
As the cam’s lobe pushes the cam follower of the contact breaker, the breaker’s points that were touching each other separately and break the primary current to flow through the ignition coil’s primary winding.
5. Distributor Cap
As the name suggests, it is the cover that protects the internal parts of the distributor system and maintains contact between the internal rotor and the spark plug wires.
It has only one post for each cylinder but contact point type ignition systems have a central post that is connected to the ignition coil to draw current from it.
6. Terminals
Inside the distributor cap, there is a terminal that corresponds to each post. The plug terminals are arranged around the periphery of the cap according to the firing order so that secondary voltage is sent to the appropriate spark plug at the correct time.
7. Distributor Shaft
The distributor shaft is located in the middle of the ignition distributor. This shaft is connected to the camshaft of the engine with the help of a gear drive. It has a cam that is used to break the point of the contact breaker.
8. Drive Gear
The ratio of the distributor gear is such that it gives the distributor one full turn for every complete turn of the crankshaft and for every two complete turns of the camshaft.
This assures that the spark plugs will burn in the correct position of the piston. The drive gear is firmly attached to the distributor shaft by means of a steel roll pin.
9. Rotor
The distributor rotor is a device in a spark ignition system that provides spark from the ignition coil for proper contact inside the distributor cap. It is driven by the camshaft of the engine and is therefore synchronized with it. As the camshaft rotates, the distributor shaft also rotates. This will cause the rotor attached to the distributor shaft to rotate.
10. Spark Advance Mechanism
It is a mechanism used in spark-ignition engines to drive the spark. Its function is to burn the fuel before the piston reaches TDC. This provides the air-fuel mixture in the cylinder to burn completely and, as a result, there will be maximum pressure on the piston.
There are usually two types of spark advance mechanism in this and i.e. centrifugal advance spark mechanism and vacuum spark advance mechanism.
