ignition points are arcing out of the gap

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December 04, 2008, 12:02:09 PM

im trying to get my 440 running. i checked spark at the plug and it is intermittent. i then set the engine to #1 firing position and turned the rotor by hand and found that the points were arcing out of the gap and to the distributor. what should i do to fix this?

Replace it with an electronic........

It's likely that you just have bad points and condensor, but it could also be the distributor itself. At the very least a Pertronix will work IF the shaft isn't real sloppy in the dist.

Hello:
I agree ....I would replace it with a Mopar Electronic system, thats what I did on my '67 GTS. End of Problems.

Maynard

Replace the capacitor. Confirm the points have a secure ground to the breaker plate, the breaker plate to the housing, the housing to the block, and the block to the battery.

I assume the coil wire is secured to a ground, or a calibrated air gap, while you are performing the visual.

If the coil wire (secondary) is not secured to a ground or a simple path to ground via a calibrated gap then the spark generated by the coil will travel a different, easier path to ground. That alternative path may be the primary circuit. The primary circuit is the low voltage (8-14 volts) wiring that includes the condensor and points.

If the spark travels from the secondary windings in the coil to the primary windings in search for a ground it will leave a carbon track inside or outside of the coil and the coil is now junk. Never fire a coil without an easy path to ground for the spark.

Does any of this help?

The points will arc when they break, and one side of the points is grounded? I have never seen secondary voltage bleed over into the primary.

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what is a calibrated air gap?

Pencil neck talk for the distance you hold the discharge end of the coil wire from ground. Usually about a 3/8 inch, give or take a little. I agree with Jim, that you would be better off in the long run to replace the point set up.

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A calibrated air gap is just another way to say the air gap is not so large the spark won't jump. A spark plug gap is a calibrated air gap. The greater the air gap the greater the resistance. The greater the resistance the greater the voltage required to ionize the air gap and jump the spark. When the gap (resistance) exceeds the available voltage level then the voltage will not jump. It'll take another path to ground.

Electrons are lazy. They will always travel the path of least resistance. If that path easier path is from the coils secondary tower over to the primary side of the coil then that's were it will go. This is why you always give the spark an easy path. Put the coil wire (cap end) against a ground. Some techs simply clip a wire to the end of the coil wire and the other end of the wire to a bolt on the manifold, valve cover, etc.

As for the condensor (capacitor). It's job is to absorb and hold the remaining voltage (electrons) left in the primary side between the coil and the points when the points open (seperate). The points are nothing more than a switch (on/off). When the points are closed: Current (electron movement) travels from the battery-ignition switch-ballast resistor-positive side of coil-through the primary windings in the coil creating a magnetic field-out the negative side to the coil onto the single black wire-across the contacts at the points- and to ground and back to the battery.

When the points open, the current stops and the magnetic field in the coil collapses across the primary and secondary windings in the coil inducing voltage in a single direction. The voltage induced into the secondary windings is what fires the spark plugs. The voltage remaining in the wire between the coil and the points will jump the points when the points open (kinda of like people jumping over water to the ferry from the dock as the ferry pulls away). This jump destroys the contact points. The condensor acts like a sponge for those electrons when the points open and releases them back when the points close again.

If the secondary voltage seeks a path to ground via the side of the coil tower it will essentually ruin the coil. You can wipe the carbon tracking off the coil but a trace path will remain and the next time it seeks a shorter path it will travel the old path again. You may be midway down the track when it finds that path again. It may also create a path through the inside of the coil that won't be diagnosed until you replace the coil.

If it's electrinic ignition, the stray secondary voltage may find it's way across a circuit board in the ignition module destroying the module.

Always give the spark an easy path to ground so as to protect the primary circuit.

i have not yet replaced the condenser.

The basic rule is to change the condensor every time you change the points. In reality the old condensor is usually better then the new one as their main enemy is moisture and the one in the distributer is dry while the other one has been sitting on a warehouse shelf. They are there to prevent the points from arcing. They do go bad and it sounds like your's is shot. Replace it.

i just purchased a mallory distributor that i saw on craigslist. i paid $60 and i also got a complete driveshaft for $100 set up for my big block duster. i decided to buy an electronic distributor now rather than wait. why put money into the points type when i could just get what i want. thank u for the help. im sure the condenser was bad. thank you