where should a ballast resistor be wired? my car has been converted from a 6v+ ground to a 12v - ground. i've heard it's a good idea to mount a ballast resistor and wire it to the coil so you get good 12v spark for starting but when the car's running it calms it down a bit. am i right in my knowledge of what a ballast resistor does? where do you wire it in at? mine definitely doesn't have one.
If you have a starter solenoid with a s and r post, you run power to the coil off the s to start (12v) and then run from the ignition to ballast then to coil for 6v during normal operation. I leave it stock, because I don't like wiring, so maybe someone else can be more help.
The ballast resistor goes in between the ignition switch and the coil + terminal. This knocks the voltage to the coil down from 12v to about 8v. But when you are cranking the engine, the starter draws the battery voltage down to about 8v anyways, so you only get about 5v at the coil, which is not enough under some conditions...so the resistor gets byp***ed during starting by connecting the R terminal on the starter solenoid or relay to the coil, giving it full battery voltage while cranking. If you are using a 6v starter, it won't have an R terminal, as it was not designed to use a ballast resistor in the first place. So, just hope that it starts ok without the byp*** wired...usually it's not a problem.
The balast resistor actually increases its resistance or effectiveness as it gets hotter…So (When wired directly from the ignition switch) right when you turn on the ignition, the coil will get some higher voltage, then as the car is on longer, the voltage will drop. You can measure this with a volt meter. You might actually get close to 12v right when turned on. Maybe a little less. Now on systems where there starter solenoid is wired in to by p*** the ballast resistor upon startup…the coil will get the 12v to start off and then act like the example above. You can wire your ignition either way…if the rest of your ignition system is healthy, there is no reason that you can't wire it directly from the ignition switch(without solenoid byp***). It should start right up. At least..I have never had a problem. Tim MBL
Its a metal wound resistor.. Resistors limit the voltage hot or cold it should knock it down to around 6 volts.To be wired properly it takes 2 wires and thats that. Dave
In a perfect world this is true. But after building several guitar amplifiers, I have noted that when the wire wound resistors heat up, the resistance changes a bit and therefore lower the voltage more. To see this...connect a volt meter to the cold side of the resistor, add voltage and watch the voltage read higher..then drop to the 8 or so volts. I measured this on my car 3 days ago. Many resistors have a drift rating for just this reason. I have also seen carbon resistors drift in the other direction. Some ballast resistors may have a higer ohms rating, and therefore lower the voltage more. Again..generally if all else is healthy, you will get your car started with either wiring setup. Its possible that it may start easier with the solenoid byp***...which is why they have it. Tim MBL
The way mine is wired, is I am using a 1940 ford column with the original on/off switch...on the cold side of the switch, I have a wire that goes to one side of the ballast resistor...on the cold side of the ballast resistor, I have a wire going to the coil. It works for me. Give it a try and if it works...leave it alone. To use the byp*** type of setup, you can have the secondary small terminal (R) of the starter solenoid hooked up to the cold side of the ballast resistor. Then..when the starter solenoid gets the 12v jolt..so does your coil..YOu will also need to have the cold side of your ignition switch hooked up to the hot side of the ballast resistor...this way...when you release your starter ****on, your coil will still have voltage..only it will be lower, cause it is fed through the resistor... Does this make any sence? Tim MBL
that only works if you have a starter solenoid with an R terminal on it. If you don't, then just leave the byp*** off, it will most likely work just fine.
Right...you need the right solenoid...sorry. what I would think is the "normal/conventionally used" solenoid should work as I mentioned above...If this is not the case...someone can correct me...But I have measured the voltages and in my experience....it worked. Tim MBL
my solenoid has three posts on it. i'm guessing this is + - and the relay terminal. so i need to wire the resistor between the relay terminal on the solenoid and the cold side of my ignition? i'm sorry if it's clear and i'm just not getting it, i'm a newb at wiring. other stuff (engine, fabrication) i'm relatively solid on but wiring is something i have limited knowledge of. especially with this car because it's been converted and i didn't do it so i have no idea where everything goes.
Need the r terminal solenoid...if you only have 3 terminals...it probably is not there. The R terminal is then connected to the cold side of the ballast resistor...sorry for any confusion.... Tim
Come to think of it….I'm pretty sure that you can't use your solenoid….if it only has the 3 terminals…cause then the solenoid would get power…when you weren't pressing the starter ****on…I'd see if you can get a solenoid from like a 57 Chevy dart or something. Then it would be hooked to the other small terminal..not the one hooked to the starter switch. Tim
I think this is how it would look in a real quick Paint. Somebody correct this if its wrong. If your starter is not like this (Three Terminal), you can add a Ford Starter Solenoid (one from an older Ford w/points) up on the fender and use it to activate your starter (Sort of like the hot start fix for a chevy starter) and pull the ballast byp*** off of it. Carry a spare resistor and the tools to change it in the glovebox. It will save your **** some day. They can burn out at the least convenient time.
Looks right to me...the purple wire that goes to the starter solenoid is connected to the (S) terminal. The Yellow wire is connected to the (R) terminal. This yellow wire can also be hooked to the cold side of the ballast...which is essentially the same thing as connecting it to the coil directly like in the diagram. TIm MBL
If you are using a modern style "key start" ignition switch, you can run another wire from the start terminal on the key switch to the coil as well as the one to the solenoid. That will put 12Vs at the coil only when the key is in the start position. When you release the key after starting, the coil is fed only through the ballast resistor. It accomplishes the same goal.
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