More than likely you will be ok using the onboard resistor, it that's what you wish to do, only IF the coil isn't too low in resistance. If the coil is one with a low primary resistance, then the onboard resistor will run too hot.   For example, the Ford yellow top coil should be used with a 1.5 ohm resistor as the two components establish the correct total circuit resistance.  By eliminating the resistor, a yellow top coil would run much too hot.    Pertronix makes a 1.5 ohm coil, among others, which would be totally  compatible with the Pertronix unit in the distributor and can run with no resistor.  By eliminating the resistor, the spark energy will be greatly increased and the Pertronix coil is designed and proven to function in this combination.  Trying to mix and match components could very well cause either the coil or resistor to run too hot and fail.  Also, I agree with the above post that a condenser doesn't know weather it's used with a 4, 6 or 8 cylinder engine. You probably have one of the numerous poor quality condensers now available.  

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I don’t believe the condensers of years past would know the difference other than the possibility that 1/2 the operations would keep it cooler on a 4 to an 8 and 1/3 on a 6 to an 8. In all the years owning a points automobile engine I only had one condenser fail and it was a combo unit it on a 1973 Monte Carlo. As stated prior I have used a Pertronics coil AND a stock 56 ballast resistor for 9 years without fail. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

I have been trying to decide whether to continue to use the internal-resistor coil as I make the switch to pertronix, or instead to swap in one of my other external-resistance coils. The instructions state that I can use any coil with an internal resistance of 1.5-3.5 ohms, and/or that total primary resistance including external resistor is not to exceed 3.5 ohms. My internally resisted coil is in the accepted range, but so are the 1.5-ohm point-type coils I have. I suspect it will work fine with either.

Curiosity has led me to try to determine what the intended application was for the internally resisted coil. The only thing I’ve been able to nail it down to is a late 60s Opel Kadett! In fact, the only factory applications I’ve found for internally-resisted coils are 4-cyl European cars.

I have 3 such coils in my possession. All 3 have approximately 3.0 ohms primary and 9500 ohms secondary. I have 4 external-resistor coils, including an original mustard top, all of which have about 1.5 ohms primary and 7700-8700 ohms secondary. I know nothing about the performance properties of these coils besides their resistances. It has me wondering whether my points troubles were caused by incompatibility between the coil and condensers, knowing the coil was probably intended for a 4-cyl and the condenser for an 8-cyl. Any ideas whether this could be the case?

Regardless, I’m probably going to go with one of my 1.5 ohm coils and not use a resistor with pertronix.

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

Looks like things are headed in the right direction. When you have the new Pertronix unit and coil installed, I think you will put your ignition issues to bed for good.   Thanks Charlie for fixing the link. I'll probably be an analog person for ever...........

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Interesting reading from Magnecor. It is refreshing to read what appears to be a transparent, no-nonsense representation of the product and its appropriate application.

I measured the resistances of my new wire set and it looks like they are about 4500 ohms per foot. This is definitely an improvement over what I had on there, which was probably deteriorated from age, oil, antifreeze, temperature, etc.

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

Fixed it.  There was an extra space at the end.


Lawrenceville, GA

Charlie, can you fix my posted link so it will open?  I think this article will explain some of what you mentioned above along with what is important, what is not and why.  Thanks.............

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Sortof off topic.

I've started checking plug wire resistance when new and writing it down.  This  helps to confirm that the new wires have no problems but also provides a baseline for future trouble shooting.  Resistance per foot can vary wildly from one wire tech to another so knowing this from the start can be a big help.


Lawrenceville, GA

https://www.magnecor.com/magnecor1/main.htm       Hopefully I did this correctly. If the link opens, on the left side of the screen click on "THE TRUTH A BOUT IGNITION WIRE CONDUCTORS".   It's a long article by Magnacore but very good..........................

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I should of added that the actual resistance with an ohm meter with its 3 or 4 volts across the probes is not a true indication of wire condition but the resistance I stated above is typical of what I'm used to seeing.  The resistance of the core is designed to reduce RMI and RFI interference.  The actual energy passes over the core (skin effect) rather than through the spiral core. Someone else with more knowledge than I on this subject could explain this much better.  

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