Plug Wires

While we were on the topic of wires, we also asked about spark plug wire technology. You probably already know about the importance of keeping your spark plug wires off of hot header tubes and the necessity of providing insulation from heat. Spark plug wires should be discarded if they are burned or discolored from touching a header tube in order to protect yourself from future ignition troubles, but Johnson also gave us a great tip to help separate marketing speak from actual useful technology when it comes to selecting spark plug wires.

"The diameter of the cable means nothing. We only make 81/2mm wire now. We used to make an 11mm spark plug wire, it looked like a towrope. It was huge and it turned out that it did nothing more than an 81/2. So it is not the size that's critical, and you can ignore that when it is advertised as a feature. What is critical is you have to use a reactive core cable with a spiral. Solid core wire just won't work, it will just disrupt the signal because it isn't able to shield the signal from electrical interference. The plug wires have to be spiral core, and as long as it is, you're in good shape. It doesn't matter what brand it is or how fat you make it, just make sure that that core is made correctly. And you will know it because if it is a spiral core wire, the manufacturer will definitely tell you right there on the box."

Test it Yourself

One of the newer products Crane has available is a Digital Ignition Tester that is pretty trick. In fact, Crane had not even planned to make it a catalog item and simply offer it to racetracks as a testing tool, but the tester became so popular with engine builders and race teams as well that the company put it in the catalog right alongside all of its other products.

"We had an analog ignition tester before, but when we designed this new digital unit, boy, it really took off," Johnson explains. "There were multiple issues that we thought a tester like this could help with. Number one, the tech line at the racetracks can easily become a headache for both the track management and race teams. Tracks can't afford to hire different people for all the different things they need to check, so they kept asking us for a checker for the rev limiter that was easy to operate, and still really accurate. They wanted something that did not require a lot of training or a lot of technical expertise, so that was the initial thrust.

"A second thing was we kept getting complaints about the disparity in the inaccuracy of rev limits with different systems. We had seen different systems where the rev limit could vary by 200 rpm, and that's not fair to a guy who thinks he's getting 6,300 and he's only getting 6,100. So we wanted a system that would be able to validate that and also be able to confirm whether it was the ignition system or the tachometer that was off. So that was the second thing going on."

Johnson says the digital ignition tester is popular with race teams because it allows them to quickly determine whether there rpm limiter is operating accurately because no one wants to get the racetrack at a disadvantage. It also allows a team that maybe having engine trouble to quickly and accurately get a determination whether the ignition system is the source of the problem or you need to look somewhere else. To Crane's credit, the tester is brand agnostic and will not only work with Crane ignitions, it will also work with MSD and Mallory systems (along with others) as well. It will also work if you are mixing and matching different brands of ignitions, coil and ignition boxes.

The ignition tester stays in your toolbox until you are ready to use it, it doesn't stay in the car and it does not require the engine to be running. Using it is relatively simple, pull the six pin connector to the ignition, plug the tester in to it, plug the spark plug wire that comes with it into the coil so that the tester can fire the coil, and it is installed. From inside the car, turn on the ignition and then turn on the switch at the ignition tester box. The tester will go through a diagnostic routine that takes about 12 seconds and then tells you the exact rev limit on the system. Also if it makes it to that point then you also know that the ignition system is working properly. To test the accuracy of your tachometer, you have about 10 seconds after getting the readout from the testing box to hit the recall button on the tachometer, you do that the tester sends a signal to the input on the tachometer, and you can actually see if there is any disparity between the rev limit displayed on the tester and what the tachometer reads. So if the box says 7,000 and the tachometer says 6,900, you know that the tachometer is off by 100 rpm at that point and can account for it on the racetrack. It's that easy.

Optical Trigger Technology

Crane uses an optical trigger technology in its distributors that is also becoming very popular. In fact, we have done dyno testing with Crane's optical trigger ignitions in previous issues of Circle Track and seen that it does, in fact, work very effectively. So why we had Johnson, we took a moment to ask him exactly what is going on with that technology.

"It is all about producing a better signal so that you can more accurately time when the spark plug fires. It's just the nature of the signal created by the optical trigger and the speed of the signal that we generate. We do it electronically, and then we convert that signal into a magnetic output so that it is understood by the ignition regardless of who's ignition it is. That is something we want to make sure is very clear, just because you run a Crane optical trigger distributor that doesn't mean you have to run a Crane box or wires. It is the speed of the signal and the fact that rpm doesn't change the accuracy of the signal. That's the nature of a magnetic signal, the higher the rpm, the broader that signal becomes, which, in turn, starts retarding your timing. By using an optical trigger, ours does not do that. It stays stable all the way to 9,900 rpm.

"The proof of that is simple. When you put a timing light on an engine with our distributor, it looks a lot more like a crank trigger because it is so stable. It only moves about a half of 1 degree at most. But a magnetic signal can jump anywhere from one half to 31/2 or 4 degrees, which is a big difference. That also makes it really tough to lean on a motor because you do not want to let it get into detonation so you have to retard the timing enough to account for that signal jumping around. You have to err on the side of caution and detune the motor basically. Because you don't have to do that with our optical trigger ignitions it's like finding free horsepower. Engine builders set their timing for maximum power and do not have to worry about. They have caught on to that and just love it."

Another difference is all of Crane's racing distributors have eliminated the mechanical advance components inside the distributor. That means there's less for you to have to tune, less mass spinning inside the distributor cap, and fewer components to wear out or cause problems. Johnson says that removing the mechanical advance helps improve accuracy, which is their number one goal.

Instead of a mechanical advance, Crane has built-in a timing retard into some of its ignition boxes. The box automatically pulls 20 degrees of timing out of the ignition from zero to 600 rpm. That makes the engine easier to start and by the time it gets up to idle, the timing retard has kicked off and the engine is running at the timing used at that rpm. This feature is especially helpful when trying to crank a hot motor in the pits or if you have stalled on the track. It, however, it isn't adjustable, so there are no concerns about racers cheating up the box to use this feature as a poor man's traction control.

Crane Cams
1830 Holsonback Drive
Daytona Beach
FL  32117