There are currently two types of ignition systems in use in cars and trucks. The first is the electronic ignition system and the second is the distributorless ignition system (DIS). You can easily tell which you have when you pop the hood by looking at the spark plugs. If there are thick wires all running to the same location, you’ve got an electronic ignition system. Conversely, if you pop the hood and see a couple/three smaller wires running from a block on top of the spark plugs, or short thick wires running to what are known as coil packs, you’ve got a DIS system.
Prior to electronic ignition, which became ubiquitous in the late 70s and early 80s, there was also the points-type ignition system. This type of ignition system can be identified by the presence of a small aluminum can mounted either on the side of the distributor or very close to it on the engine. Quite often, except with newer electronic ignition systems, both points-type and electronic systems will also have what is called a ballast resistor mounted to the bulkhead behind and above the engine.
If you’re building up a strip burner basically from scratch, you’re going to need to decide what kind of ignition system you want to use. Unless we’re already building on a car that’s got a computer, our choices are going to be limited to standard electronic or points-type systems. I’m going to discuss the pros and cons of each to help you decide which one you want to go with.
What Tells Fire to Go to Your Spark Plugs
Your ignition system is the electronic/electrical system in your car that sends properly timed sparks to your spark plugs to ignite the air-fuel mixture in the combustion chamber. On most ignition systems, the charge that creates the spark is created and contained by an inductive ignition coil. However, some performance ignition systems use a capacitor to store this charge.
Whether an ignition system uses a capacitor or an inductor, the circuit creating the charge is broken, causing an electrical field on the ignition primary side to collapse, sending the charge to the proper plug on the secondary side. Points-type and most electronic ignition systems use a cap and rotor to pass the secondary, high current-voltage spark to the plugs. DIS systems use a series of sensors and switches to open and close the primary ignition circuit and fire the secondary side.
Standard Points Type Ignition System
The points-type ignition system uses a set of contacts, known as points, and a capacitor (to filter AC noise), known as a condenser, to break the electrical circuit, creating the spark. The points are attached to a plate in the distributor. As the distributor shaft rotates, a cam riding on a bumper on the points rides up and breaks the points contact. For this reason these are also known as breaker-type ignitions.
Pros and Cons of Points-Type Ignition Systems
These ignition systems are capable of passing large amounts of current and electricity, which makes them great for high performance automotive ignition systems. They’re also extremely accurate, also making them great race cars. I had an old Mopar (a Charger) that I first used on an Accel dual-point (the distributor held two sets of points instead of one) distributor in it. My big Holley 1100 double-pumper almost couldn’t pump too much fuel to burn. They’re also really easy to troubleshoot. No spark at the plug? Got power to the ballast resistor/coil? Pull the cap and make sure the points are opening and closing properly and are properly gapped.
The problem is keeping even single-point distributors properly adjusted. Performance engines vibrate, causing the adjuster to move over time. You’ll be adjusting the points between each pass on your strip burner to get the best performance on each run, I guarantee it. Also, even when you use the recommended lube on the cam and rider pad, both wear over time, especially the pad, as do the springs and plates inside the distributor, making them even harder to keep properly adjusted for maximum performance.
However, when converting from a stock points system, they’re the easiest to do. Typically it’s just a matter of sticking in the new distributor, hooking up the power, installing a new coil and wiring it, and putting on new plug wires, and then timing it. It can be done in a couple of hours in your garage with minimal tools.
Electronic Ignition Systems
Electronic ignition systems use a magnetic field to open and close the ignition primary circuit. Instead of an ignition breaker, a special type of transistor (which is called the pickup) that works with a magnetism is used. Instead of a cam spinning on the distributor shaft, a component known as a reluctor rotates with the shaft. This reluctor has several small magnets on it which pass the pickup as the shaft rotates.
The primary circuit is opened when the reluctor magnet passes the pickup, sending a signal to the electronic ignition control module. The control module reads engine speed and throttle position to determine the timing and temperature for the spark. The ignition control module then opens and closes the primary circuit on the ignition coil, sending the spark to the distributor cap, through the ignition rotor, back through the cap, and finally to the plug.
Pros and Cons of Electronic Ignition Systems
If you’re converting a car that wasn’t factory-equipped with an electronic ignition, the cons start with the difficulty of the conversion process, unless you install a factory electronic system (See image above the Direct Connection Mopar Performance ignition system I used). This is what I did with my Charger. Out with the old distributor, in with the new, mount the new racing coil I bought, and hook up a few wires and connectors. The hardest part was finding a spot for the control module and the over-sized racing coil that I liked.
Take a look at the MSD performance electronic ignition system in the image above. Not only will you need to replace the distributor and find a coil mounting location you like (although this coil actually fits in the factory location and mount), but you’re going to have to route the wires for the control module through the bulkhead between engine and passenger compartments. On top of that, you’ll have to find a place that you can securely mount the ignition control module. Taking that one step further, if you get one that allows you to make adjustments on the fly, you’ll have to find a place to securely mount in and that you can safely reach to make those adjustments.
More things can go wrong with an electronic ignition system, too. The plate that the pickup is mounted to can wear and move, causing the reluctor and pickup to move out of adjustment and stop working. The reluctor itself can wear and chip in extreme cases. Competition systems have chips that control the function of the controller that can fail or wiggle loose and are not easy to diagnose right away. Don’t get the controller properly grounded and you can experience an intermittent ignition failure that is as hard to track as the Abominable Snowman.
The aforementioned ability to make ignition system adjustments while driving is one of the major selling points for high-end high-performance competition ignition systems. Most performance controllers are also equipped with rev limiters that can save both you and your motor in a runaway condition at the track. Keeping the spark timing (and heat) properly adjusted is much easier with electronic ignition systems. No moving parts that rub together and electronics that learn over time make this possible.
Electronic ignitions also allow for ignition coils that deliver more spark, such as capacitive discharge (CD) systems. Since they’re mostly solid-state, there is less to wear out. They’re also not as susceptible to timing problems when things in the engine compartment get wet.
Installation time varies depending on a few factors. The longest and most difficult install is going to be the conversion from an old points-type ignition system to an aftermarket competition electronic ignition system. Install time can take anywhere from a few hours to a couple of afternoons, depending on how familiar you are with tools and how much you know about automotive electrical systems.
Distributor-less Ignition Systems
These are the new kids on the block. They’ve only been in regular use since about the year 2000, although they aren’t the only electronic ignition systems in use at the moment. They are the most involved ignition systems, although as the name implies, we’ve done away with the distributor. Now we use sensors to trigger the opening and closing of the primary ignition circuit.
Instead of a distributor with a cap and rotor direction the fire to the individual plugs, DIS ignition systems use a coil pack. A car can either have a single coil pack for multiple packs. Each coil pack contains at least one ground wire and multiple “hot” wires, all of which lead to the ignition control module, which have now become engine control computers that accept a wide variety of sensor inputs. Either or both a cam and/or a crankshaft sensor are used to tell the computer where the engine is in the rotation and what cylinder to fire.
Pros and Cons of Distributor-less Ignition Systems
Because DIS systems use a larger number of input parameters to control spark duration, timing, and temperature, they are much more accurate, especially at higher engine speeds. This is extremely cool if your strip burner is also your daily driver and/or you’re operating on a tight budget. No need to dive in with tools and meters to adjust this and that. The computer takes care of everything. Even better, if you’ve upgraded your computer, you can plug your laptop in and make adjustments to everything on the fly. You can also swap out system “maps” between passes at the push of a button and click of a mouse.
If you’re working on an older car that was factory equipped with a points type ignition, forget converting to a DIS system unless you’re installing a special crate motor of you’ve got the tools, time, and experience to assemble a DIS motor. Cam and crank timing are minute with points and older electronic ignition systems, but they become microscopic when computers and DIS systems come into play. In most cases, every bit of wiring is going to need to be replaced.
Again, the level of control that a computer-controlled ignition system puts at your fingertip is amazing. Removing the wear item that a distributor is just makes your ignition that much more adjustable and adaptable. Over time, as wear gradually occurs, the computer can make small adjustments to keep performance at its peek.
Conversely, quite a bit more can go wrong, too. With points and older electronic systems, if ignition timing goes out of adjustment, fixing it is quick and really easy. DIS systems make you hook up meters and testers. Finding out why no spark is getting to the plugs involves quite a bit more testing and checking – wiring, coil packs, connections, sensors – some of which can be located behind the engine, and more. A no start condition can take you hours to find, but be nothing more than a connector with a wire loose because we’re talking about such small voltages and currents.
What I’d Choose to Install in My Next Strip Burner
What kind of ignition system I’d install in my next strip burner would depend on what year and make it is, the condition of the existing wiring, and if I’m building up a Nostalgia Drags car or something more of an Unlimited Drags car. If I’m going Nostalgia and electronic was available from the factory, then points it is.
However, if I’m going overall “ease of use”, which means both during install and on race day, I’m going with a high-performance aftermarket system like the MSD system pictured above. They’re not as hard to install as they look, they look cool, and they work really well. There’s also the fact that I’m not going to build anything that first hit the streets after the year 1980, and there’s no way I’m plunking down all the dinero that going high-performance DIS would require.