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Discussion Starter #1
We have a 68 coupe with stock 289 2bl 2100 with distributor with points. We seem to go through a lot of points. Is there a step down transformer or voltage regulator on this vehicle that I'm missing? I don't see anything on the vehicle. I finally have the carb squared away so everything is good now until I burn my next set of points.
 

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There is supposed to be a resistor wire at the ignition switch leading to the coil that drops the voltage. If someone has bypassed it or something and there is a full 12 volts at the coil (and points) then they indeed will be short-lived.
 

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There is a resistance wire in the harness from the ignition switch (PINK wire) to the firewall. This adds 1.5 ohms impedance to the ignition primary circuit, in addition to the 1.5 ohms provided by the internal windings in the ignition coil. The BEST way to check would be either using an ohmmeter between the ignition switch "C" terminal and the ignition coil + terminal or a voltage drop test, with the engine running, between the battery + post and the ignition coil+ post. If you have insufficient resistance you can replace the resistance wire, if defective, or add a ballast resistor to the circuit, but the ballast needs to be installed to the ignition switch side of where the BROWN wire from the starter solenoid is spliced in, typically at the engine compartment side of the firewall plug.

A couple things that can aid in the destruction of points are a bad ignition condenser or a coil that's wired in reverse polarity.
 

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Discussion Starter #5
Man you guys are good and fast. Will check it out this weekend. There is a decent chance that has been bypassed but I need to check it out. I usually replace the condenser and points at the same time. I've had the carb so messed up but that is in the past. Points are classic and easy enough to set. What do you think about electronic? Is it worth the spend?
 

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Some go with Pertronix Ignitor in the stock distributor but you'll have to follow their instructions for installation with or without the resistor wire. I have two cars, one running points, and one running an Ignitor, but I have a points plate with points and condenser ready in case of a failure.
 

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What is over looked is that the coil also produces a spark in the primary circuit of the coil the same time it’s producing a spark in the secondary coil when the magnetic field collapses. This spark energy is what damages the points. The condenser is put in place to absorb this spark. However if the coil ballast has been eliminated it’s possible the condenser is not up to handling the extra energy.

Check the power to the coil as well as installing a top quality condenser
 

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Most points car engines have two feeds for the coil. One is a direct 12v from the starter relay (ford) or solenoid(everything else) that is only present during starting to provide a stronger spark for starting. When it has started it continues to run on the power fed through the resistor which lessens the load on the coil and points. Chrysler had a goofy 4 terminal resistor on theirs before going to an external electronic ignition module that would melt down like the big Ford one.

Personally I will immediately convert every engine I have to electronic ignition ASAP. I replaced and adjusted too many points on small engines and hate points...
 

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Points are awesome for cars that stay below around 5500 rpms. Huge fat spark, excellent for lighting off the mix. Minor maintenance issue around 20-30k miles; you check the points, clean as needed. Cheap, simple, really good, if adjusted properly and maintained.

Electronic units produce an intense, but very short spark. Essentially no maintenance, higher cost. Effective to most any RPM you care to name.

So there are advantages, and disadvantages.
 

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I converted back from the Petronix II to points. While obviously not as hot, I don't need maximum performance. Mine is basically a look and a sound with not many miles per year. I did have a Petronix failure on another classic. My take is the Petronix II is the most prone to failure.
 

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IMHO, rpm has nothing to do with the effectiveness of points IF they are designed to handle the higher rev's.

My Honda CB350 has dual points and a red line of 10,500. No problems all the way to the redline and beyond. The 289 Cobras would routinely rev to 7,500 with a stock K code distributor, and K code Mustangs are good for 6,500 + rpm.


I do understand why some folks can't get 7,500 miles between points adjustments, and several times that number between replacements.

It's because there is a fault in the ignition system, or a poorly thought out modification. In either case, the fault can be corrected. Points get a ton of bad press because it's easier to blame something as substandard, than it is to learn how a system works, and thereby learn how to diagnose and fix a problem.

No need to throw out the baby with the bathwater.


Z
 

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Discussion Starter #14
Thanks for the thoughts on electronic vs points. Any recommendations on "good quality" points and condenser? I've been going to Autozone or O'Reillys and just use what they have in stock. Might need to be more selective.
 
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