Distributor Buyer’s Guide
- The ignition system’s distributor is a small device that distributes high voltage current from the ignition coil to the corresponding cylinder.
- There are two main components of this assembly: the distributor cap and rotor.
- Replace the distributor every 50,000 miles because the rotor and cap deteriorate over time.
- OE replacement distributors typically cost around $20 to $570.
- Replacing a failing distributor will guarantee uncompromised engine performance, reliability, and peace of mind.
Have you ever wondered what happens inside your car whenever you insert and turn your key in the ignition switch? To turn the engine on, cars are integrated with an ignition system. There are different types of ignition systems in existence, and most rely on an ignition distributor. This buyer’s guide will help you pick the best replacement distributor for your vehicle.
What is a distributor?
The ignition system’s distributor is a small device that distributes high voltage current from the ignition coil to the corresponding cylinder. Its main function is to channel the high-voltage current from the coil to the spark plug. At the same time, the distributor controls the timing advance of the ignition coil by maintaining the optimal firing order. The most common distributor design features a cap with protruding tubes along the exterior’s sidewall. However, the design varies depending on the manufacturer.
Parts of the ignition distributor
There are two main components of this assembly: the distributor cap and rotor. Here are the different parts you can find inside the aessmbly.
The cap serves as the housing’s top cover and protects all the internal parts that make up the distributor. It has protruding posts along its sides. Each of these posts is connected to a cylinder. In a contact point ignition system, there’s a central post that connects to the ignition coil. The central post is where the distributor receives the current from the coil.
Inside the distributor cap is a rotor that’s driven by the camshaft. It's important that the rotor's movement is synchronized to the engine’s camshaft. The rotor is designed to pass electric current to every internal plug terminal.
The distributor shaft is found in the middle of the assembly. A gear drive connects it to the engine’s camshaft, which spins it along with the rotor. The distributor shaft has a cam which it uses to break the point of the contact breaker.
The distributor’s contact breaker is a mechanical switch that controls the timing of the sparks that are transferred to the spark plug. There are two ends on a contact breaker, which are fixed and movable.
The cam is attached to the distributor shaft. It pushes the cam follower and breaker points to break the current. To open the contact breaker points, the cam features lobes, which are assigned to a corresponding cylinder.
The capacitor has a parallel connection to the breaker points. It's responsible for keeping the breaker's contact points of from overheating. It reverses the flow of high-voltage current through the primary coil. It also prevents premature wearing of the breaker points by suppressing sparking.
Spark Advance Mechanism
This component assures the perfect ignition timing for optimal engine power and fuel economy. There are two types of spark advance mechanisms: centrifugal and vacuum. A centrifugal or mechanical spark advance utilize weights and springs to rotate and configure the position of the timing sensor’s shaft relative to the engine. On the other hand, the vacuum advance mechanism uses a manifold vacuum that works in conjunction with the rotation of the distributor’s position sensor mounting plate.
How does a distributor work?
The rotor spins inside the cap as the engine camshafts spin the distributor shaft. The rotor spins past multiple contacts, depending on the number of cylinders. As the tip of the rotor passes each contact, the coil generates an electric pulse, which arcs across the tiny gap between the rotor tip and contact. The current then flows through the spark plug wire onto the spark plug, which sends it to the cylinder as part of the combustion process.
How to choose the right distributor
The distributor is responsible for distributing high-voltage electricity to the cylinders at the correct time for engine ignition to happen. If you begin to experience hard starting, misfiring, or stalling, there’s a good chance that the ignition distributor has to be replaced. Here are some things that you should look into when buying a replacement distributor.
What type of distributor system does your vehicle have?
If your vehicle was built in 1975 or earlier, it's most likely equipped with a mechanical ignition system, which is also known as the original distributor cap style. You can always upgrade this to a high electronic ignition (HEI) without any compatibility problems.
Meanwhile, an electronic ignition system is used for vehicles built in the late 1970s and early 1980s. This system is usually equipped with an electronic ignition module. If your vehicle has one, you can upgrade to an MSD Ultimate HEI without encountering compatibility issues.
A distributor is no longer necessary for vehicles that were built during the late 1980s and early 1990s, They have a distributorless ignition system. If your vehicle belongs in this category, you only need to replace your spark plugs at 60,000-mile intervals.
How do you use your vehicle?
If you mostly use your vehicle for racing, then you need to choose high-performance distributors. Race cars generally use this type of distributor because it's specially made to meet the demands of a racing vehicle.
However, if your vehicle is intended mainly for street driving, it's better to buy a distributor without race-only features. These features can cost more and can affect your vehicle's overall drivability.
Symptoms of a failing distributor
The distributor rotor constantly spins to keep the engine running. In turn, the engine sends large amounts of electric pulses to the rotor through the ignition coil. You should replace the distributor every 50,000 miles because the rotor and cap deteriorate over time. If your rotor begins to fail, the electric current won’t be distributed to the corresponding spark plugs. As a result, you could experience engine stall and a handful of other problems. Here are the symptoms of a busted rotor and cap that you should look out for.
Carbon buildup inside the distributor cap of a worn distributor can cause your engine to misfire. Carbon buildup affects the component’s capacity to conduct electricity. It shorts the voltage and compromises the connection inside the terminal. Bad point connections may also lead to engine misfires, as they cause engine overrun and timing issues.
Engine that won’t start
If the distributor cap isn't fitted properly, the engine won’t be able to send the spark that’s required to move the pistons in the cylinders. Since the spark can’t be transported to the corresponding spark plug, the car won’t start.
Check Engine Light keeps on coming on
The Check Engine Light is meant to light up if the system senses engine-related issues. A bad distributor will trigger the Check Engine Light warning.
Weird engine noises
A malfunctioning rotor and cap can cause the cylinders to misfire. If the cylinders fail to fire, they produce tapping or clicking noises. As soon as you begin hearing noises under your hood, immediately seek a certified mechanic’s help, and have your car thoroughly checked.
Importance of replacing a damaged distributor
Avoid the possibility of your car stalling by replacing failing components. A malfunctioning distributor cap and rotor could lead to serious engine compartment issues. Replacing a failing distributor will guarantee uncompromised engine performance, reliability, and peace of mind. You’re also achieving optimum fuel economy if your distributor is working properly.
How much is a distributor?
CarParts.com sells some of the most affordable and reliable OE replacement distributors on the market. These typically cost around $39 to $570. Ignition system distributors are sold either individually or as part of a kit. A kit may include spark plug wires, 3-prong oval connectors, and ignition module. OE replacement distributors with direct-fit installation are available, as well as performance upgrade parts. You may also choose from remanufactured and brand new parts.
Although you can replace the distributor on your own, we still recommend scheduling an appointment with a certified mechanic. Since a distributor is directly linked to your vehicle’s power supply, proper evaluation and adequate fitting are important. The mechanic can also trace any underlying problems surrounding the part to be replaced.
Enter your vehicle’s year, make, and model into our vehicle selector to find the most compatible distributor for your vehicle.