Factory resistor block needed with new coil?

[38convsedan]

Rewiring my 38. Stock 6 volt positive ground with new coil that has built in resistor.
Question: Do I need to use original wiring block with the resistor?
If not, should I use a 4 gang block with bus connecting all four terminals?
Or do I use two 2 gang block?

[Lawson Cox]

You just need to send your old coil to Skip Haney to get it rebuilt and all other questions are moot. My 2¢

[koates]

New coil with built in resistor ?? Does this mean it is not the original Ford coil that sits on top of the distributor but is a can type coil that sits separately from the distributor. What is the ohms resistance of the primary winding of your coil ? Need to know that to work out if you need a separate resistor or not. Regards, Kevin.

[38convsedan]

Kevin,
The car has a 1949 8BA with a Pertronix Flame-Thrower canister 1.5 ohm coil.
Thanks!

Steve

[mfirth]

You need the correct Pertronix coil or you will have nothing but trouble. Personally I'd stick with points. Have seen too many electronic units fail.

[38convsedan]

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I do have traditional points/condenser.
The coil is a Pertronix brand.

[koates]

I woould have thought that if your Pertronix coil has a built in resistor then it would be a 3 ohm primary winding and not a 1.5 ohm winding as you stated. Pertronix coils are usually 1.5 ohm and 12 volts but you have a six volt system. Not sure why you have chosen that Pertronix coil. I would be using a standard 6 volt coil. The important thing here is to have the correct current draw in the coil primary circuit which should be 2 to 4 amps depending if you are measuring the current with the engine running or not running with points closed and ignition on. I could be wrong but thought Pertronix coils were designed for electronic ignition and not points systems like yours. If the primary current is too high you will burn out points fairly quickly. Regards, Kevin.

[rotorwrench]

Can type coils and especially modern 1.5 Ohm primary type coils don't need a ballast on 6-volts. The ballast was for the Mallory design coils that Ford used with the helmet and crab type distributors.

The built in resistor is the "primary coil". There is no separate resistor in there as most people think. The secondary coil is for the inductance so it's resistance doesn't affect the primary except to step up voltage for high tension sparks. It's the number of windings in the primary coil that gives the resistance. External resitors are current control devices for coils so that they don't overheat. A ballast is only needed when the voltage is too high for the primary coil to deal with. It makes them operate with more reliability.

[38convsedan]

Thanks Rotorwrench!!
I appreciate your insight….
Steve

[38convsedan]

And thank you to all who responded! I really appreciate your help!!!

[Ziggster]

I was just going through this exact same issue with respect to the requirement for a ballast resistor for my 6V negative ground wiring system. I also posted my question on the HAMB and some folks said I didn’t need the ballast resistor. Some said I did, so I found it very confusing. In my searching for help, J came across this post from the Barn which helped. I dug out the ballast resistor I had purchased which had 1.6 ohms stamped on it, and verified the resistance with my multi-meter which confirmed it was around 1.6 - 1.7 ohms. I then checked the resistance of the coil itself, and found it to be 0.2 - 0.3 ohms. So going by what he said about the maximum voltage for the points, I figured that for sure I needed the ballast resistor.

[38convsedan]

Thank you for the detailed info!!

[rotorwrench]

A 3.0 Ohm primary type coil is commonly used on 12-volt systems with no need for external ballast. The 6-volt systems primarily use the 1.5 Ohm can type coils with no ballast. If the primary side resistance is that low then there is likely an internal problem with the coil.

I can see some problems with the statements in that Barn post. Most ballasts for a 1.5 Ohm primary coil used in a 12-volt system will be from 1.3 to 1.5 Ohms. Ballasts are current control device but it also controls the voltage applied. I don't generally get into the voltage needs of a system since they vary from one design to another, The Mallory design coils that Ford used in the early V8 era have specific condenser and current control devices for their design. They used around .5 to .8 Ohms value for the ballast resistor on all those old V8s up through 1948 when they started the change over to the Holley Load-O-Matic distributor systems for the 8BA era. They went back to can type coils with 1.5 Ohm primaries and used no ballast at all in the 8BA time frame.

[Ziggster]

Originally Posted by rotorwrench

A 3.0 Ohm primary type coil is commonly used on 12-volt systems with no need for external ballast. The 6-volt systems primarily use the 1.5 Ohm can type coils with no ballast. If the primary side resistance is that low then there is likely an internal problem with the coil.

I can see some problems with the statements in that Barn post. Most ballasts for a 1.5 Ohm primary coil used in a 12-volt system will be from 1.3 to 1.5 Ohms. Ballasts are current control device but it also controls the voltage applied. I don't generally get into the voltage needs of a system since they vary from one design to another, The Mallory design coils that Ford used in the early V8 era have specific condenser and current control devices for their design. They used around .5 to .8 Ohms value for the ballast resistor on all those old V8s up through 1948 when they started the change over to the Holley Load-O-Matic distributor systems for the 8BA era. They went back to can type coils with 1.5 Ohm primaries and used no ballast at all in the 8BA time frame.

I have a helmet distributor with a new integral coil. As mentioned, I measured 0.2 - 0.3 ohms across the coil with the condenser removed. Is this value too low?