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Replacing Points With Electronic Ignition

Lev Lowrie wrote (reprinted from the Slant Six News):

Are you still running a points type distributor? Are you tired of getting a crick in your back replacing the points and condenser? Or maybe dropping one of the hold down screws into the case and having to pull the distributor anyway? There is a solution.

Point/condenser types of ignitions have been around for more than a half century and while they have progressed to where they are considered reliable, they have some definite drawbacks.

First of all, they require regular maintenance. By 10,000 miles a set of points is shot whether the car is running or not. The pivot and bushing wear so the movable points rattle around, especially at higher RPM's. The contact surfaces wear and become pitted and no longer conduct current well. The springs become weak and don't close the points as fast, and the rubbing block wears off and the gap closes up. The correct way to set points is not by their air gap when open but the degrees of dwell (the amount of time the points are closed). To get the correct setting requires the use of a dwell meter. But still this setting can change after only a few hundred miles of driving.

In 1973 Chrysler replaced the points type ignition with an "electronic" type. Instead of points opening and closing to complete a circuit, it features a stationary contact which passes current to a rotating reluctor, set at a fixed distance. Since this system has no contacting parts, an electric current is a constant amount on each pulse, and can be much hotter, for more complete burning of fuel. Since there is no point bounce and no parts to wear out, it not only gives a hotter constant spark, but also eliminates almost all maintenance. It also offers increased secondary voltage and current for improved starting and will keep the spark plugs cleaner and give greater plug mileage as well as increased performance throughout the whole RPM range. AND YOU WON'T HAVE TO CHANGE POINTS ANY MORE.

You can replace the points type ignition in your Mopar with the new improved electronic type. while the procedure is not a completely foolproof bolt in, it almost is. And you don't need an Electronic Engineering degree to accomplish the basically simple procedure. For those with 70-72 cars, it is (other than mounting the control box) a simple bolt in. For 69 and earlier it requires a little more effort, but still can be accomplished in less than an hour, with only hand tools.

One easy but expensive method is to purchase the conversion kit (#P3690789) and on 70-72s just bolt it in and plug it in. The kit contains a new distributor, control box and ballast resistor. Those with 69 and earlier cars will have to read on for hook-up instructions.

A second and far less costly way is to locate a 73 or later Mopar in a wrecking yard. From it get:

  1. The distributor...remove the hold down bolt, the cap , unplug it and lift it out.
  2. The Electronic Control Unit..or control box
  3. The dual ballast resistor (with 4 outlet prongs)
  4. The wiring harness, which consists of the wires connecting the control box, the distributor, and the ballast resistor.

Be sure to get everything.

Be sure to get the mounting bolt for the dual ballast resistor as the screw from your single resistor will not fit. Don't forget the screw that holds the plug into the control box and the screws that mount the control box to the car.

It is probably a good idea to buy a new ballast resistor. They are cheap and do go out from time to time. It is also a good idea to keep a spare in the car because when the resistor does go out it gives no warning. If needed or wanted replacement control boxes can be purchased at most discount parts stores or the dealership.

Check the distributor (1) Rock the center shaft back and forth. if there is any perceptible movement,get another distributor. (2) Make sure the "O" ring under the distributor is in good shape. (3) If you have a vacuum pump, test the vacuum advance to see that it works. (4) Check the air gap (the distance between the pickup and the reluctor). It should be .008 and must be checked with a non-magnetic feeler gauge. Make sure that the reluctor has not been contacting the pickup.

Next mount the control box on the car, away from heat and vibration. A good spot for this on an A body is the inner fender. Make sure the control box and screws make good contact (a good ground) to the car. Next mount the dual ballast resistor, usually in place of the original one.

At this point it is a good idea to disconnect the battery. It will probably save your fusible link. Then remove the distributor cap and locate the rotor. Disconnect the wire to the coil, unbolt the hold down bolt and lift the distributor out of the engine. Install the new distributor making sure the rotor points to exactly the same place.

Now comes the tricky part--the wiring! Note that each of the new wires to the ballast resistor have have a lose wire (actually two wires...one is brown the other is blue).

Plug the harness into the distributor and the control box (be sure to re-install the hold down screw). You will find off the harness a black wire with a yellow stripe, this connects directly to the negative (-) side of the coil.

At the ballast resistor plug-in, one side has a blue wire and a brown wire. Find the plug on your old ballast resistor that has two blue wires and attach them all together.

Make up a new brown wire, long enough to go from the positive (+) side of the coil to the loose brown wire on the new ballast resistor. Connect the new brown wire. the loose brown wire from the new plug, and the two wires from the other side of the old resistor plug (blue and brown) together. That is 4 wires all connected into one. The old wire to the (+) side of the coil coil will now hang loose, just tape it off.

Now go back and read those last two paragraphs again to make sure you've got it right. AND THAT'S IT!

Oh yes everything has to be plugged in correctly or it won't start. Don't forget to re-connect the battery or it won't start anyway.

Remember to tuck the new harness away, along with the old harness. Make sure there are no bare wires showing and tape everything up nice and neat.

Since you're going through all this trouble, do things right and install new spark plugs, distributor cap and rotor. Check the plug wires and replace as necessary.

One additional thing to check is the ignition coil. It may work fine with the point type ignition but may develop a misfire or worse with the higher output of the electronic.

Once you have done this conversion and seen the advantages and increased performance, your only question will be...Why didn't I do this sooner?

Other people wrote...

Russell Mendivil wrote about the Petronix electronic ignition kit:

This kit all fits in your existing distributor where the points and condenser used to go. There is a little sleeve that fits over the distributor shaft and the new rotor fits over this. One wire goes where the wire that used to go from the points to the coil goes. The other goes to the other side of the coil. It comes with good instructions and even a little plastic piece
to adjust the gap. It's also only half the price of the Mopar kit.

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