Benefits of Electronic Ignition System Upgrades
For many enthusiasts that delve into a classic vehicle project it is often the first time they come across the standard breaker-point ignition system used in most cars up through the early 1970s. These original points ignition systems were standard equipment on every domestic engine, be it in inline-six or big block V8 back in the day. This mechanical ignition system was simple and effective for the fuels and base timing used in that period (though some that have attempted to set up dual point distributors might argue the simplicity fact).
The breaker points system was made up of the ignition points with condenser within the distributor housing that opened and closed using lobes on the distributor shaft, along with an ignition coil (the primary ignition system), while a traditional distributor cap, rotor, and spark plug wires (secondary ignition system) finished out the ignition system to get the voltage to the spark plugs. However, being a mechanical system, the breaker points were prone to wearing, burning/arcing, mechanical rpm limitations, and in need of constant adjustment.
In the early 1970s Ford, GM, and Chrysler did just that by introducing factory electronic ignition systems. Ford’s Duraspark system used an external transistorized ignition module with traditional coil, as did Chrysler’s Electronic Ignition System. General Motors, on the other hand, went a slightly different route by replacing points and condenser with electronic ignition with its High Energy Ignition, or HEI. The HEI system not only utilized a complete under-cap electronic ignition module, but GM relocated the ignition coil to reside within the distributor cap itself, making the HEI system self-contained within the distributor body. All these systems replaced the mechanical breaker points with an electronic pickup assembly with no moving parts.
Over the years many people have upgraded their breaker points systems by replacing the points and condenser with electronic ignition using factory or factory style electronic ignition conversion parts, and they do work great for mild street performance or daily driver-type vehicles. However, finding the ignition modules, wiring connectors, and so forth gets more difficult with each passing year. With GM’s HEI distributor system being the most popular “drop in electronic distributor” upgrade for those on a budget, even in non GM engine platforms, it has by far been the most accessible as an aftermarket upgrade. That said, we’ll review your electronic ignition conversion upgrade choices from mild to wild here in this guide.
While we have already mentioned a few of the benefits in our opening copy, such as no moving parts to wear and no maintenance requirements, there are several additional reasons to update your ride with some form of electronic ignition conversion. An electronic ignition provides a hotter spark with a higher voltage, which allows a wider spark plug gap and a solid spark output to a higher rpm range, which many performance-built engines can take advantage of. The efficiency of an electronic ignition means more complete combustion, which in turn not only makes more power, but is also more efficient (less emissions, better fuel economy, etc.). It is a win-win all around when upgrading to electronic ignition in your vehicle.
Leaving breaker points systems behind us and focusing on only electronic ignition systems, we wanted to briefly touch on the distinct types of electronic ignition systems and their installation requirements or difficulties. There are three main electronic ignition system types we will discuss:
- Coil On Plug/Coil Near Plug
Distributor-Based Electronic Ignition This is the most popular retrofit by bar, as it is a simple and effective upgrade for most any engine. Options include upgrading the breaker points to a drop-in electronic module or upgrading the complete distributor. Some upgrades require an external ignition amplifier or control box, and it is wise to upgrade the ignition coil to something more suitable to the higher voltage requirements as well. Distributor-based electronic ignition solutions are available from Pertronix ignition, MSD ignition, and more.
Distributorless Electronic Ignition In the early 1990s the OEMs began replacing the distributor-based electronic ignition systems with distributorless electronic ignitions. These systems often used a camshaft position sensor in place of the electronic distributor assembly along with coil “packs.” The typical V8 of the day would have a cam sensor mounted in the old distributor mounting hole, a crankshaft position sensor (either inside the block as part of the crankshaft, or externally on the crankshaft damper) and two coil packs that fired four cylinders each. This is known as a “waste spark” system. Aftermarket crank trigger systems are technically distributorless, as the old distributor housing is only used for firing the proper spark plug and all ignition control and timing is done externally.
Coil On Plug/Coil Near Plug Electronic Ignition To further rid the engine of moving parts the OEMs would soon drop the cam position sensor (essentially a shortened distributor with just the lower shaft and gear with electronics mounted on top), coil packs, and plug wires all together for the Coil On Plug (COP) system. With each cylinder having its own ignition coil there were no longer any moving parts in the electronic ignition system, no plug wires to misfire, fewer connections, and the coils could provide more spark energy with longer saturation time since they only have to fire for their assigned cylinder versus one coil firing for all eight cylinders. Not to mention you could control individual cylinder timing with factory or aftermarket EFI engine management. Coil Near Plug (CNP) gets its name from the fact the coils aren’t mounted directly on the plug, but usually on the valve/cam cover with a short secondary ignition spark plug wire to the spark plug. It all comes down to packaging.
Both distributorless and COP/CNP systems can be quite involved from a retrofit standpoint and generally are only mentioned here for those that are dealing with modern crate engine installs (Ford’s Coyote, GM’s LS, and so on) with computer controlled ignition systems. MSD does offer its Direct Ignition System, which is a Coil Near Plug conversion for small and big Chevys and small block Fords. Our focus, though, will be on distributor-based electronic ignition upgrades.
There are several upgrade paths you can take to convert points to electronic ignition and move on from your tired and worn breaker points ignition system. The most popular upgrade paths we’ve found include:
- Under Cap Electronic Ignition Conversion Module
- Direct Replacement “Ready to Run” Electronic Distributor
- External Electronic Ignition Amplifier with Magnetic Trigger
Further details with pros and cons of their installation are found below.
For those that have, perhaps, a unique or rare distributor, or are looking to keep things stock looking under the hood, a simple drop in “under cap” points to electronic ignition conversion kit module that replaces the breaker points assembly is a great solution. The big name here in this field of points conversion is the Pertronix Ignitor, but you’ll find similar offerings from Mallory, FAST, and others. These modules install in place of the breaker points ignition and work with your factory mechanical and vacuum advance systems. A points to electronic ignition conversion kit will work with most stock coils if you really want to keep a restoration/original look, but we recommend a performance ignition coil to really work together with the module. A little paint and detailing and you can usually “hide” the aftermarket coil by making it look like the OEM coil too.
These points conversion kit systems often require bypassing the factory resistance wire or ballast resistor assembly that the points ignition system used, so you’ll either need to run a minimum 14 gauge (12-gauge is better) switched 12V source wire right from your ignition switch that is hot in start and run or use your factory wiring to trigger a standard 12-volt relay that you can then power the module directly from the battery. This upgrade is simple, budget friendly, and rids your stock ignition system of the mechanical points setup. It is also the most “low key” solution if that is a concern for your build.
The answer here often relies on your automotive knowledge and abilities. Many enthusiasts can quickly “stab” a distributor in and set their base ignition timing in a matter of minutes, some even by the sound of the engine’s idle. While others have trouble even finding the distributor in the engine bay. That’s fine, we all had to start somewhere and we’re here to learn, but if the idea of pulling the distributor out gives your stomach butterflies you may wish to stick to the under cap upgrades we mentioned previously, as they are really just simple screwdriver work.
That said, if you’re game to update the whole distributor in your quest for electronic ignition you won’t be sorry that you made the effort to do so. Complete electronic ignition conversion distributors utilize a built-in ignition module and optical or magnetic sensor in place of the traditional breaker points system. These electronic ignition distributors are often available with adjustable vacuum advance units and tunable mechanical advance via swapping out weights and/or springs, such as an MSD distributor. MSD’s line of Ready to Run distributors are popular due to their basic wiring setup. Most require a specific coil ohm resistance that can handle the higher output (usually noted in the product instructions or in our “related items” section of the product page), but often will work with an OEM coil if you’re upgrading in stages.
GM’s HEI distributor, with built in ignition coil has become such a popular upgrade in this segment that several companies offer a GM HEI-style electronic ignition distributor with Ford or other engine shaft/gear fitments, including our own Speedway Motors line of HEI-style electronic distributors. While purists may cringe at the look of a GM HEI electronic distributor sitting front and center on their small block Ford engine, the compact unit works great, saves the hassle of mounting a separate coil, and is simplicity personified when it comes to wiring, as all you must do is provide a key switched 12-volt wire to the “BAT” terminal on the HEI unit to power it and you are off and running!
As your engine’s performance level increases, especially if it is via forced induction, nitrous, or other power adder, having greater control over ignition timing and keeping the spark across the spark plug’s electrode from being blown out is imperative to keeping your engine running its best.
We like to look at these electronic ignition upgrades accordingly: If you have some minor performance upgrades an under cap conversion is perfect. Moving up to some real engine modifications like aluminum heads, performance camshaft, higher compression, and the like, then we suggest replacing the distributor and pairing it with a capable ignition coil. But when you get to making big steam, you need to take your electronic ignition conversion to the next level with an external ignition controller/amplifier.
Using an external electronic ignition controller, like those from MSD ignition, offers several benefits. Many provide a built-in rev limiter like the super popular MSD 6AL, part of the MSD 6 Series ignitions to keep your engine’s max rpms in check. While under cap conversions can have this feature as well, you must gain access to it under the cap, whereas the external ignition box rev limiter switches are easier to access, or the rev limit can even be accessed via software.
Furthermore, many of these external electronic ignition amplifiers utilize a multiple spark output, usually up to 3,000 rpm, to create a hotter spark and aid in full combustion. Their built in capacitors allow for higher voltage output, something that an under cap ignition module does not have the room for. There are models that feature programmable control for such things as a full timing curve, nitrous retard, and boost-referenced timing control all via PC software that allows simple adjustments via a laptop and data cable connected to the ignition box.
External electronic ignition boxes can be installed as an add-on to an existing electronic ignition powered distributor, or better yet, can be used with a locked distributor housing a magnetic pickup, or a crank trigger assembly. So, if you are already running an electronic ignition, you often don’t have to ditch your current components to see the benefits of an external electronic ignition amplifier, as it can “piggy back” your stock system and use the distributor’s pickup as a trigger since these external ignition boxes offer multiple wiring options, and many applications can be wired with plug-and-play coil adapter harnesses.
Early breaker points ignition systems used rather small diameter female socket style distributor caps. These sockets required a certain type of spark plug wire terminal to properly mate with the distributor cap and most of these points based ignitions used 7mm spark plug wires. As the OEMs moved into electronic ignition systems in the 1970s the hotter spark allowed for greater timing advance, but this could also generate what is known as crossfire, when the rotor’s arc jumps to the wrong distributor cap plug wire terminal.
This was addressed by moving to a larger diameter cap, spacing the terminals further apart, while also moving to a male distributor cap terminal (universally referred to as an HEI terminal). There are some cap conversion kits available for MSD’s Ford and GM distributors but using an HEI-style distributor will net you the wider cap specs as well.
As noted, these larger caps use HEI-style terminals and require the correct HEI-spec plug wires to make everything work together. Today’s low resistance 8mm or larger performance plug wires are just the ticket for your upgraded electronic ignition conversion system. You can learn more about spark plug wire design and choices in our Toolbox guide on performance spark plug wires.
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