Spark Plug Magic

So it’s time for a tune-up & you’re interested in better mileage and perhaps a bit more power. You’d like to maximize both the expense of the spark plugs and the time spent changing them. Well here’s a magic trick that has shown up to 22% increases in torque and similar increases in fuel efficiency. While many of you have heard about indexing the spark plugs, we're going to go even further and turn the plugs into pencil torches This will make it virtually impossible to have misfires and promote a much more complete combustion, yielding more torque and mileage.
The project starts with a brand new set of copper core spark plugs.
This trick doesn not work with platinum, iridium, split, halo, multi-electrode, or anything other than conventional spark plugs. You will need a drill, drill press, or lathe (which is what I use), with a drill bit the same diameter as your center electrode (3/32” for the illustrated set) and a 1/16” bit. If using the drill or drill press, you should have a vise suitable for holding the spark plug while drilling. As a last resort, Vise Grips might work (though I never tried that). Never ever hold the spark plug with your hand while drilling!! Of course you’ll need your handy-dandy spark plug gapping tool, a set of pliers, either sand paper or an ignition file, and a fine tip magic marker.



For the indexing, you will probably need indexing washers. These are varying thickness copper washers available from Jegs, Summit, and many auto parts stores. There are 3 different types of indexing washers. There is the standard 14 mm flat washer, the tapered washer, and the less common flat 18 mm washer. Be sure to purchase the correct type for your engine.
First bend the outer electrode away with your pliers, exposing the center electrode. With your larger drill bit, cup the end of the center electrode creating a satellite dish effect. Be careful to drill it dead center, and only drill deep enough to create the cup. On turbo and extreme performance engines, use a drill bit a xize or 2 smaller than the center electrode. The sharp edge left by the larger bit may create hot spots and lead to detonation under load.
The next step is to bend the outer electrode back into place and get it centered. You want it centered not only side to side, but also front to rear. You should have the tip of the outer electrode about even with the edge of the center electrode. It is not necessary to gap it at this point, just get it close by eyeball. Next drill a 1/16” hole dead center in the outer electrode. It is more critical on high output engines to get the hole dead center side-to-side, as offset holes lead to thin spots that will hold heat better, and again lead to detonation. Notice how little of the drill bit actually sticks out of the chuck. It is really easy to break these small bits. Using the file or sand paper, debur all sharp edges. Run the bit through the outer electrode hole again to clean out any small pieces of metal that may have worked their way in while deburring. Now it’s time to properly gap and blueprint the plug. The outer electrode should be centered over the center electrode, should be square, and should have the 1/16" hole centered over the cup in the center electrode.
How this works is the center electrode will act like a satellite dish and “broadcast” the flame kernel toward the outer electrode. The 1/16” hole in the outer electrode will allow this flame to pass right through, giving the pencil torch effect. The pencil torch flame then extends into the swirling air-fuel charge and ignites far more fuel than would otherwise ignite, and it ignites it earlier in the combustion cycle so that the chemical energy in the fuel is more completely converted into heat energy in the cylinder when and where it counts!
After we've modified the spark plugs, we need to install them. Low and behold, there is a magic way of doing this that yields additional gains as well. You want the outer electrode to face the head, exposing 350 degrees of the cylinder’s combustion chamber to the spark. A little towards the exhaust valve is acceptable. Using your magic marker, draw a line along the side of the spark plug that will indicate where the outer electrode connects to the body of the plug. This allows you to see the position of the outer electrode without pulling the cylinder head. Start by installing your spark plugs one at a time in the first cylinder until the line you drew indicates that the outer electrode is facing correctly. Then move to the next cylinder. I find that on a V-8 I can usually index about 5 plugs before needing the indexing washers.