Ignition Coil

• An ignition coil is a type of transformer that converts low voltage power from the battery to high voltage power that’s needed to activate the spark plug.
• It consists of copper or brass coils, terminals, and iron core.
• Ignition coils vary in types, which include canister, coil-on-plug, coil pack, and ignition blocks.
• A malfunctioning ignition coil can cause engine backfire, misfiring, and other engine problems.
• It costs around $16 to $2,300.
• Installing an ignition coil replacement on your own is possible if you have the right tools and know-how.

Before you’re able to drive your car, you must start your engine by turning the ignition switch clockwise using a key. To enable electric current to reach your engine, the car is equipped with an ignition coil. This piece of transformer converts the low voltage power from the battery to activate the spark plug and ignite the fuel in the combustion chambers.

A basic car ignition coil features an iron core, coils, and terminals, working together to receive, convert, and pass electric current from the battery to the spark plug.

A car battery is only capable of putting out 12 volts but the engine needs more than that. This is where the ignition coils come into play.

Inside an ignition coil, you’ll find a primary and secondary coil. The primary coil generates a magnetic field when the low-voltage current reaches it. A contact breaker collapses this magnetic field to induce a high-voltage pulse in the secondary winding that is enough to reach the spark plug.

Ignition coils were invented in the mid-18th century as a specialized version of induction coils that were invented in 1836. Engineers sought further advancements by developing the induction coil, which eventually led to more complex systems.

Before car ignition coils, car manufacturers used magnetos to supply enough voltage to generate sparks in internal combustion vehicles. It wasn’t until 1910 when carmakers started incorporating battery-and-coil systems in production vehicles.

Early ignition coils were made from varnish and paper that have insulated high-voltage windings. These were put inside a draw-steel can and filled with asphalt or oil to provide insulation and protect it from moisture. Nowadays, the coils in modern vehicles are cast in filled epoxy resins that seep into any voids within the winding.

There are different types of ignition coils available in the market, and knowing what type your car uses can make your OE replacement purchase a lot easier. Each type varies in terms of design, circuit layout, and capacity.

Canister type

The can-type coil is one of the oldest types of ignition coil found in classic cars with rotating high-voltage distribution and contact breaker control. It incorporates oil that serves as its insulator and coolant, while modern versions have dry insulation.

Coil-on-plug

Coil-on-plug, also known as pencil, plug shaft, or simply plug, is a type of ignition coil that is found directly on top of the spark plug. They normally don’t need ignition cables but high-voltage connectors are a strict requirement. With respect to its design, the number of ignition coil needs to match the number of spark plugs, as each one needs an ignition coil.

Coil pack system

This type of car coil is a single component of multiple plug shafts attached to a “rail,” which is mounted on a series of spark plugs. The main advantage of this design is that you won’t need multiple connecting cables, which also helps in the aesthetic value of your engine compartment. The number of plug shafts on the rail depends on the number of cylinders in your engine.

Ignition blocks

Ignition coil blocks come either with single or double spark technology. Single spark blocks have ignition cables supplying power to a single cylinder, while dual spark ignition coils supply simultaneous power to two cylinders.

Your vehicle's ignition coil is engineered to last around 100,000 miles, but the actual lifespan can vary depending on several factors, such as your vehicle's model, your driving routes or terrain, and how you drive. Talk to a technician if you believe your ignition coil has prematurely failed.

Worn-out ignition coils cause your engine to backfire, so much so that you’ll end up sacrificing your car’s fuel efficiency. If you don’t address this problem, your car might develop further issues like engine misfiring, which could render to your engine losing some power or occasional stalling.

If the problem worsens, your car might not start or stall on the road. Although the problems stated can be due to other reasons, it is still best to have a mechanic check your car as soon as you notice even a minor issue. Replacing your worn-out ignition coils as soon as possible can save you from further hassles that can arise if the problem persists.

If you are not looking for a component that will enhance your performance, you can get a stock replacement ignition coil designed to replace an old or busted one.

However, note that there are also coils that are made for specific road use. These are street or strip coils and race only coils. The street coils are normally rated from 35,000 to 55,000 volts. These coils can give a significantly greater performance than stock ignition coils. They provide easier and quicker starting, better throttle response, and improved gas mileage.

Another thing that will help you choose the best ignition coil is by knowing what kind of distributor your car has. This will help you minimize your choices for a coil. If you have an HEI type of distributor, for instance, then should only buy an ignition coil that can fit within the distributor cap or one that entirely replaces the distributor cap. Externally mounted coils for "points style distributors" are the kind of coils that you can find the most in the market. If your ignition system doesn't have a distributor, you will still need an ignition coil for it to operate.

If you’re looking for an OE replacement ignition coil for your car, the next thing is to determine the quantity of part you need; be it a single part, kit, or set. Pencil ignition coils and blocks are sold individually and in sets, so if you’re after a coil pack, specify it by selecting the specific type in the design category.

Individual ignition coils cost roughly around $16 to $630 (An ignition coil pack costs around $2,300). If they are part of a kit, they may cost around $60 to $900. Meanwhile, if they are part of a set, they may cost between $50 and $1,100. Note that these prices don't include installation or service costs.

If you have the right tools and a bit of DIY skill, you can certainly save a lot of money if you change the ignition coil yourself. In this guide, we'll show you how you can replace the ignition coil in your car:

Needed tools and materials:

• Screwdriver
• Socket wrench

Step 1: Pulling out the wires

With the hood propped open and the ignition key turned off, disconnect the negative battery terminal and unplug the wires running from the center of the ignition coil to the distributor cap. Make sure that the wires don't get mixed up. Take note that vehicles with conventional points have a green wire that leads from the side of the distributor and goes into the negative side of the coil. Cars with points replacement units, on the other have, have a red wire that goes into the positive side of the coil and a black one that goes into the negative side.

Step 2: Removing the oil coil

Loosen the coil mounting bolts and remove the old ignition coil from the distributor cap. The coil is likely to be attached to the mounting bracket by a single bolt, so you will have to loosen this bolt as well to remove the coil as well. If the coil also comes with a rubber insulator and carbon button and spring, remove them as well.

Step 3: Preparing for installation

Clean the cavity where you removed the ignition coil and install a new carbon button and spring or rubber insulator if necessary. Make sure to coat the rubber with dielectric tune-up grease before putting it back in its place.

Step 4: Installing the new coil

Install the new coil into the cavity and secure the two leads into the cap connector. Once the coil is in place, insert and tighten the coil mounting brackets and plug all the wires back into the coil, double-checking that the positive and negatives wires go to their respective terminals. Reconnect the negative battery terminal, close the hood, and test drive the car.