Ignition Basics - Has Your Truck Lost Its Spark

Ignition Basics And How To Improve Them Thanks To Pertronix

By Grant Peterson

One of the furthest things from smart that we could do today is keep a points-type distributor in a classic truck, let alone any vehicle. With all the advances and simplifying that's been done to ignition systems in recent years, it would give us all a leg-up on performance and economy to employ an electronic distributor as the driving force in sparking internal combustion in motion. Prices have come down from what they were in the past, and you don't really need one of those big ignition boxes that look like you should be at the track instead of the 7-Eleven getting a hot dog. As the years go by and parts become more plug-and-play, the desire to adjust, fine-tune, and maintain tricky little things like point gap, dwell, and advance curves has dwindled substantially, not to mention all those who don't even know how or where to start, let alone understanding them.

Pertronix is a household name when it comes to ignitions, and it now offers an all-new polished distributor that's CNC'd from a solid piece of billet 6061 T-6 aluminum, and is part of its famous Flame-Thrower line. The cool things about this surprisingly affordable unit is that it has a roller bearing at the top and an oil-impregnated copper powder bushing at the bottom of the oversize tempered 1/2-inch shaft. With these being CNC'd by Pertronix, you won't find the mass production sloppy tolerances and years of wear that comes with some of the old standby electronic swaps.

Now that we know that its distributors are made better--what makes them work better? One of the biggest advantages to upgrading to the Flame-Thrower electronic ignition is that with a points-type ignition when the rpm climbs, it's harder to control the dwell period. What is dwell? First of all, it is the amount of angle out of 360 degrees that the points are closed in one rotation of the distributor shaft. During that dwell period while the points are closed, the coil is essentially building up voltage--known as coil saturation--to produce the next spark when the points open back up, and is therefore easy to see that as the rpm climbs that the system has to work much harder to achieve a hot enough spark. At high enough rpm, the points could actually be a governor of sorts, as they bounce off each other and cut out any real dwell period. Pertronix developed its Igniter II module to cure this problem, and is basically the electronic iteration of breaker points. This little module provides Pertronix's Adaptive Dwell Control and varies the dwell angle as needed by the engine's rpm, resulting in an average of four times more available energy between 3,000 and 5,000 rpm, as well as twice as much voltage at the spark plug. In short, that is why points are outdated. You'll never have to get near this Pertronix distributor with a piece of sandpaper and feeler gauge. Pertronix hasn't reinvented the wheel; they've just made it roll better.

The recipient of this beautiful setup is a '72 C-10 short-wide that was bought out of the local paper and is on par with what many start out with for a decently priced truck project. It runs and drives, but needs help in every area. Our first goal is to get the Goodwrench 350 running as best we can before we get to any cosmetics. It may seem like we're putting lipstick on a pig, but we want to make sure it'll get around town to pick up parts along the way, and with gas at a premium it's important to get it burning efficiently.