Keeping the stock engine and converting to 12 V. Question...original distributor hold the coil which is 6V, how do I connect. 12V through a ballast resistor..or ??? Help would be much appreciated.
The correct ballast resistor will work to protect the coil and points from too much voltage. That's what Chevy did in 55...
I'm not sure what you mean by "Hold the coil" ? There's a lot of threads on this, do a search. You need to change out the coil to 12v. You may or may not need a ballast resistor depending on the coil. Are your gauges 12 or 6 volts?
Just put an adaptor on a 35 distributor so I could use a conventional round coil. Available through various vendors. Got a coil with internal resistor and a bracket that bolted on with a water pump bolt. Adaptor came with mounting screws and condenser. Easy to change and works well
Not HOLD the coil...HAS the coil...my typo. I am keep the stock distributor and coil setup. Some 6V instruments will go thru an electronic power supply that will bring the 12V down to 6V. I don't want to change the look much on the dash from the original, so 12v side gauges will be located somewhere. ( gas & temp gauges )
Thanks guys, but the idea here is to retain the stock coil mounted on the distributor. Surely this must have been done in the past. Appreciate all input.
The way I've always done this was to get a ballast resister for a 57 or so Chevy and run my 12 volt input through that. It seems as though I've seen a 12 volt replacement coil for those Dizzy's, maybe Bob Drake? THANX RICH
I used the stock diving helmet distributor on my '40 with the stock coil when I converted it to 12 volts. I used a ballast resistor to reduce the voltage down to 6 volts and the stock resistor/circuit breaker system reduced it further to about 4.5 volts as per original. The coil burned out. I replaced it with another one I had. It burned out. I bought the adapter that permits you to run a regular 12 volt coil and everything worked just fine. I am still not sure why the stock coil does not work but it doesn't.
Let's revive this thread for just a moment, please! I was going to run a 14ga to my coil, a new 12v one, with a ballast between the coil and distributor. Am I right in doing that? I think that way once I want to upgrade the distributor, I only have to rewire from it to the coil. Time and location keep me from wanting to replace the distributor now.
In 1957 Ford went to 12 Volt. They mounted a resister on the motor and the 12-V switched wire went to it. The coil and dist still ran on 6-V. More little-known information is that all the Gauges still operated on 6-V through a voltage controller mounted on the back of the instrument panel. This basic system ran up through 1964 with little variations. I have used that stock Ford resister on many early Ford Dist like yours in the past with no issues. Should still work today. Don't make it difficult.
That guage system with the resister was used upto 1984, then some "smart" person at Ford decided to use 12V magnetic gauges like GM. I worked in Ford service then and the gauges were a nightmare! We had tons of problems with them. The old system was as reliable as Lassie! It took a while for Ford to get their act together again.
@Pist-n-Broke I may need a new coil, would you get a 12v or 6v, in that case? The one I've got is an unknown commodity, if so, would you simply but the resistor after the coil? Have you seen this, from Vintage Auto Garage, for the gauges? I'm definitely not afraid of factory Ford resistor though. https://vintageautogarage.com/multi-gauge-reducer-oil-gas-temp-gauge-12-to-6-volt-mgr1/
I can't say for others , but, my 1964 ford F250, that my Dad purchased new, has a voltage dropping resistor on the back side of the instrument panel. AND a dropping resistor that went to the coil. When I tried to swap coils one time with an average 12v coil, it would not start. Back to the one that came on it new, runs fine. Runs fine now in 2025. Factory original coil. Never bothered to do a dynamic voltage test on the input of the coil lead to see what the input voltage is. It's a ranch truck, runs. You can use something like this to adjust your 12-15volt battery system to 6v for the old dash instruments. I am not sure if it will provide enough amperes for the distributor. Worth a try. Easy solution. I have home made a better quality job but that was in the late 1970s and I worked in a nice small research laboratory. https://www.amazon.com/DROK-Waterproof-Converter-Adjustable-Transformer/dp/B00C0KL1OM/ref=sr_1_6?adgrpid=1232553570823975&dib=eyJ2IjoiMSJ9.Tbds63XX1ekJ02GOGAgxKYQUahk3jdh6e8ferqzYC_kq1FDjeMI1prYeBuIXshnnicR-w2es96_5b7NmqMicV45oo2yVSAS-9S4n1eODYuKwxzvar2ZpdPBeTn-fOsg8ySbEBg3q3V_866343POiXoanXvmxavABznLDSq-6FS6_kUBIjY7QiI-l6oJFAP02N0nlTa-lnvwvzH5sMUSu4V22t9js5A61MFwfdHjWxIw.gmt-FpKxOIZWKD7IapEwHQdowZau3t5_7ugIYepiBUE&dib_tag=se&hvadid=77034730271181&hvbmt=bb&hvdev=c&hvlocphy=79021&hvnetw=s&hvqmt=b&hvtargid=kwd-77034891355745:loc-190&hydadcr=18308_13576916&keywords=5v+to+3v+voltage+regulator&mcid=129602a29eda3259a9a3f0fbf0dc8b50&qid=1748549111&sr=8-6&th=1 This is an amazon link, may take a bit of time to load because HAMB I think checks to see if it is a BS link. But will load up.
Parts houses used to sell a matched set of coil and dropping resistor. When you asked for a coil for a project they would always ask if you wanted the matching resistor to that specific coil. New coils were wound for a specific resistor to get the most effective combo. I recall parts houses USED to give coil specs which would include the electrical resistance, output voltage and matching resistance resistor for that coil. Not all coils are the same, varies from manufacture to manufacture and output voltage and energy.
Not that it matters, but for clarity, Ford went to 12 volts in 1956, not 57. They used 12 volt gauges for one year only 1956. They had so many issues they went back to 6 volt gauges with a voltage regulator on the back of the dash for 1957, and through the 1980's. It reduced the voltage from 12 volts to 6 volts.
Use the voltage regulator box I listed a link to on amazon. Your 12v batt starts at 12.5 and up to 14.5 volts when charging and running down the street, should be at least 13.8v. Set the regulator box to 7.0 volts for your dash lights and instruments because a 6v system usually charges out of the generator at 7.0 to 7.4 volts. So when running your 6v instruments are looking at as high as 7.4 volts when cruising down the road on a stock 6v system. This way you have a constant voltage to the dash instruments and lights with no flicker or swag when cruising vs parked with the ignition on. Remember when the old 6v generator system, when at low speed the dash lights and instruments used to surge back and forth with the voltage regulator cutting in and out ? ? With the above mentioned regulator box that will not happen any more with a 12v battery system. We used to use a 8v generator on 6v system on the tractors on the ranch. It would make the starter spin faster and most 6v voltage regulators with tweaking on the voltage regulator would put out 8v. Yes there is 8v generator and battery systems on tractors and industrial equipment. Even my 1925 dodge is a 12v system.
Don't know if anyone caught this but the ballast resistor is wired in BEFORE the coil. Not between the coil and distrubutor.
Most people don't know that the points opening and closing does not just make a connect and dis-connect. Each spark discharge at the spark plug is actually a resonating signal like a radio transmission in fact the usual resonating frequency of the conventional points and condenser circuit is about 28 megahertz as I recall. About the same as a CB radio ! So that blue flash you see is not like lighting ZAPP it is a spitting buzz. It's a capacitor ( ignition condenser ) inductor ( the coil ) and resistor ( the in line resistor ) circuit. To get the maximum zap they all have to be correctly balanced.
Kelly, I'm not one to do the Mix-n-Match job on electronic parts. The resistor goes on the Power side pre Coil on everything I've done. I know Ford marked the Coils 12-V even though they are post resister and in my book that makes them actually 6-V. Not all resisters do the same resistance job. Coil output is actually rated on Ohms not Volts. When choosing a new Coil I would buy the same one that came Stock with the Dist you're connecting to, then decide what resister you need. I'm only 77 years young and growing up doing this stuff was a lot easier with only 2 combinations things electric pertaining to Hot Rods. It's only confusing if you make it that way. Personally, I stay away from one aftermarket persons idea of how to do it when a Factory engineer designed a system that worked well for years so the vintageautogarage unit would not be on my go to list. The total aftermarket industry is built so "they" make money, not usually to fix or even help you with a problem. Ever tried to get your $$$ back when one of those things let all the Smoke out of your gauges they told you it would protect?
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