In this age of electronic fuel injection and ignition it’s hard to believe there are still some running around with a points-trigged ignition system. The concept of breaker-points ignition is all about storing large amounts of electricity and discharging it at just the right time to sync with an engine’s cylinder timing events.
The ignition coil is little more than a transformer, which converts electricity from one form, or value, to another. In this case, we’re taking 12-14 volts of electricity and changing it to 20,000-50,000 volts so it can jump a 0.035-inch spark plug gap. In order to discharge large amounts of current the ignition coil needs two circuits (primary and secondary) and a switching mechanism. The primary circuit consists of the positive and negative terminals on the coil. The secondary circuit consists of the positive terminal and the discharge terminal at the coil’s center, which goes to the distributor.
Ignition points open and close via the rotating distributor cam in time with the firing of each spark plug. When the points are closed a powerful field of electricity builds in the coil awaiting the moment when points open, discharging via the coil lead to the distributor to fire each spark plug. Ignition points do a pretty good job when they are fresh with plenty of lubrication at the rubbing block, clean contacts, and good spring tension. Problems abound when contact points become pitted and wear out. Performance suffers when this happens, typically leading to hard starting and misfires.
PerTronix Performance Products conceived their breakerless electronic ignition system when it became clear motorists needed a solution to problematic ignition points. In fact, PerTronix was born of the need for an electronic ignition retrofit for industrial applications where engines rack up a lot of hours and go through a set of points in no time. PerTronix then developed quick-change electronic ignition retrofits for automotive applications—and the list of applications keeps growing.
We’re working with Ted’s Carburetor Shop rebuilding a classic Delco distributor for small- and big-block Chevy applications. We’ve opted for the classic, original PerTronix Ignitor in black, which is the economical solution for enthusiasts on a budget who are tired of changing and gapping ignition points.
A Delco distributor rebuild and PerTronix upgrade is something you can do in your home garage or you can ship it off to Ted’s Carburetor where it will receive the close attention of Ted Granger, who rebuilds and curves thousands of these distributors every year.
The first thing Ted does when he receives a distributor is a close inspection to see what’s there to begin with. He looks for inappropriate and excessively worn parts. Ted gets a lot of already rebuilt distributors mindlessly thrown together by mass rebuilders encompassing the wrong parts and poor tuning. Ted’s job is to rebuild distributors employing all of the right parts and proper tuning. This square hole is a reference mark for the rotor. However, it is also a reference point for the distributor drive gear at the other end of the shaft. This hole and the gear reference dimple must be in alignment.
Here’s the dimple in the distributor drive gear that should be lined up with the hole at the top of the shaft in the advance head. Not all gears, especially aftermarket drive gears, will have this dimple. When there’s no dimple, you have to rely on the distributor gear tension pin and how it relates to the reference hole in the advance head.
Distributor shafts can be hard to get out of the housing due to carbon build-up and crud. Saturate the bushings and shaft with penetrating lubricant, then work the shaft back and forth aggressively until it comes free.
This is the mechanical advance limiter pin, which limits mechanical advance travel. It should have a bushing around it, which further limits travel and total timing. This one doesn’t have a bushing. Look to Summit Racing Equipment for a replacement bushing along with advance weights and springs, which come in kit form.
Here’s the distributor shaft and advance head. The advance head slides onto the shaft and is secured at the top. It works hand in hand with the flyweights and springs, which control spark timing as rpm increases. The vacuum advance goes to work when you start out. As vehicle and engine speed increase and intake manifold vacuum decreases, this mechanical advance mechanism goes to work giving us total advance above 3,000 rpm.
Breaker plate removal is next, beginning with the breaker points and condenser, which will not be used again.
The vacuum advance unit is retained with two machine screws. Vacuum has to be applied to the advance unit in order to move the breaker plate enough to remove this screw. You can also move the breaker plate with a screwdriver to get at this screw.
We’re removing the vacuum advance at this time, which will be replaced. Vacuum advance units go bad when the diaphragm tears, rendering the unit a throwaway.
The breaker plate, which is cycled by the vacuum advance unit, is retained with this C-clip mid-section. Once this C-clip is removed, the breaker plate comes right off. Be careful removing this C-clip. Wear eye protection and make sure the C-clip doesn’t go flying across your garage.
This is the Delco distributor’s lubrication pocket, which is packed full of grease to keep the shaft and bushings lubricated. We will fill this cavity with grease during assembly.
The PerTronix Ignitor comes with everything you’re going to need to get your Delco up and running. This is a Hall effect system where the reluctor ring, which contains eight magnets, fastens to the advance head. The reluctor revolves past the pick-up module mounted on the breaker plate, performing the same task as the ignition points. It works as an electronic switch to allow ignition coil saturation and discharge.
The first order of business is to fill the lubrication pocket with high-temperature wheel bearing grease, which is what Ted suggests. At high temperatures this grease flows to the bushings and shaft to provide lubrication. Engine oil works its way up the shaft to provide lubrication as well.
This felt ring is saturated with penetrating lube, providing lubrication to the bushings and shaft. This felt ring should be sprayed with lube every 25,000 miles.
PerTronix provided us with a new vacuum advance unit, which is installed as shown using two machine screws.
We’re installing the breaker plate at this time, attaching it to the vacuum advance arm. The C-clip is reinstalled to keep the breaker plate in place. Check the breaker plate for freedom of movement. If it doesn’t move you won’t get the benefit of vacuum advance.
Next, we’re mating the shaft and the advance head prior to installation in the housing.
The PerTronix reluctor ring is tied to the advance head and shaft at this time using two self-locking nuts provided in the kit.
The shaft and bushings have been lubricated with wheel bearing grease, which is very effective according to Ted.
The distributor shaft endplay is controlled by how many shims are installed between the drive gear and the housing. You want 0.025-0.030-inch endplay. Add shims to reduce endplay. Subtract shims to increase endplay.
The reluctor ring is secured at the advance head as shown here. We have one nut securing the reluctor for setup purposes. You will need both nuts installed and tightened before adjusting the air gap between the pick-up and the reluctor.
The PerTronix Ignitor pick-up module has been installed and secured. Make sure the pickup wires (red and black) are clear of the breaker plate and advance head.
Next are the mechanical advance flyweights and springs. Apply a thin film of grease between the flyweights and the advance head. Check them for freedom of movement.
We’re installing the distributor rotor to the advance head using the hardware provided by PerTronix. These locknuts are secured with a 3/8-inch socket. Do not overtighten or you will crack the rotor.
The air gap between the reluctor ring and the pick-up module is checked next. You want a 0.020-0.030-inch air gap, according to Ted. What you don’t want is contact between the two. PerTronix provides brass shim washers in the kit to adjust the air gap. We didn’t need any shims.
Ted checks every distributor with a run-up on this classic Sun distributor tester. Unless you’re modifying your engine with a hot cam and the like, stock mechanical advance springs will deliver a seamless advance path.
Our completed Delco distributor is ready for action thanks to PerTronix and Ted’s Carburetor. Ted stands behind every distributor build and is ready to take your call if there’s a problem. PerTronix also offers excellent customer service and tech support should you have any questions. PerTronix tells us one of the most common mistakes people make is forgetting to install the ground wire between the breaker plate and the housing, which yields no-start and rough running.
PerTronix is the best source for all ignition parts for classic Delco and late-model HEI ignition systems. We’re talking high-caliber ignition parts like this distributor cap and rotor, which offer brass construction for reduced corrosion and pitting, along with excellent conductivity.