This may be a bit of a stereotype, but we're going to make it anyway: Racers are mechanical people.
Whether on the dyno like you see here or in the race car, problems with modern digital ign
See, that wasn't as bad as you thought it was going to be, was it? What we mean is that racers are normally quite comfortable with the mechanical aspects of working on their race cars. Moving linkages, setting toe, measuring camber, moving around lead to get the correct crossweight, repairing damaged crush panels, you get the idea. Mechanical people are logical, they can visualize how the movement of one component affects another, and share usual method for understanding how something works is to dig in, get their hands dirty, and figure it out by doing.
The race cars ignition system, however, doesn't have much going on mechanically. Other than the moving parts in the distributor, practically everything else is all about moving electrons through either circuit boards or wires. We're still not to the territory of nerds in white lab coats, but it's a far cry from bolting up a set of shocks or cutting off a mangled bumper.
Crane’s optical trigger technology used in its distributors is an advanced method for timi
That's why it often seems that ignition problems can give racers the biggest headaches. The problems can't always be determined by a simple visual inspection, and understanding why something does or does not work often requires a different method of thinking for the racer who is more comfortable working with the mechanical parts of his race car.
If this doesn't describe you, congratulations. But for the rest of us, we sat down with Crane Cams' Terry Johnson, who heads up company's ignition products division, to get some tips the current state-of-the-art in race ignition technology. He also shared some excellent insights on how to avoid ignition issues he commonly sees racers suffering from at racetracks across the country.
Grounds and Connectors
Modern digital ignition boxes require a consistent, clean signal to work properly. Johnson
"I go to the racetracks, and I get to see a lot of cars," Johnson says, "and grounding is by far the biggest and most common problem that I see. Whatever you want to call it, inferior, not enough, low-grade, insufficient, poorly done, it all comes down to not being able to provide an adequate ground to the ignition system. I think ground straps or something that racers don't think about too much because it doesn't make them any faster, but if you're grounds are not good they sure will make you slower.
"Coming in a close second in that category is poor connectors that do not provide an adequate path for the signal to cross over. Poor quality connectors just aren't going to work, especially now that there are no more analog ignitions being produced by anybody. A digital ignition has to have a clean signal. If you have a dirty signal caused by insufficient or poor quality connectors, you're going to radiate noise off of them and just have problems. Then when the engine is missing, it always seems to be the box's fault—it's never your car. But it doesn't matter what brand ignition box you are using, if you have inferior harnessing, a modern digital ignition box isn't going to like that. Back when we were running analog boxes, it didn't care as much about the signal to get away with poor connectors. The new digital boxes have a lot of advantages over the old analog technology, but they do require that you have a crisp, clear signal."
Johnson says that weather pack connectors, which are popular among racers and engine builders, are a good option because they provide a solid connection with little resistance to electricity. Crane also uses what is called a "Deutsch" connector in racing distributors. "The Deutsche design is a far superior plug," he says. "The only reason that everybody doesn't use it is because they are so stinking expensive, but it is the absolute best connector you can buy so we feel our customers deserve it. All of our distributors come with that, and we also send along the mating plug as well as four feet of wire so the customer doesn't have to go out and buy the mate for the plug."
Crane’s Digital Ignition Tester provides both tracks and race teams with an easy, accurate
"The problem that gets a lot of racers isn't just the hardware or the ground, it's also the routing of the wires," Johnson continues. "I see it a lot with how guys will route the mag trigger lead that goes from the ignition to the distributor. And a lot of guys think that because they have put insulation around it like you see for spark plug wires designed to protect them from heat that they have shielded that wire. But they haven't achieved anything in terms of providing protection from electrical interference. I have seen that in an enormous amount of cars.
"To do it right, have a couple of choices there. For example, you may have heard of the term ‘twisted pair.' If you get the cable from us, we do provide a twisted pair set of wires. That's where you have the purple and the green wires braided together. By braiding them together one turn per inch, it actually creates a shield for those leads along the entire length of the wire that protects it from electrical interference. Or, you can buy a harness that has a coated shield sleeve that goes over it that's braided and is grounded on one end. Those are the two ways to protect the signal from electronic interference."
Johnson also warns that you have to be careful about routing wires too close together. "I've seen where guys are really trying to have a nice clean installation in their engine compartment and they've got that alternator wire going right by the distributor, so they take that wire and distributor wire and zip tie it all together nice and tight. Hey, I agree that looks great, but now the racer is scratching his head trying to figure out why the ignition just isn't working like it should. All that high voltage coming off the alternator wire disrupts the signal. The same thing can happen if you zip tie the coil wire to that mag lead. You do not want to do anything that will disrupt that signal coming from the mag lead, and that is why we tell everybody that mag lead, the twisted pair, from the distributor to the ignition should have nothing tied to it that entire length of travel."
Crane’s optical trigger distributor utilizes a stainless steel disc with holes punched in
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
Don’t be fooled by marketing that promotes an ultra-thick spark plug wire as better. The m
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.