Hot Rod Forum banner
1 - 7 of 7 Posts

·
Registered
Joined
·
800 Posts
Discussion Starter · #1 ·
We have a debate going on with friends. What is the purpose of having a ballast resister on your cars wiring? Some said you have to have a ballast resister if your running points ignition. Others say you don't need a ballast at all and everything works fine. Any opinions? I'm talking about the square ceramic looking thing with a connection on both ends. Also, how do you know if the ballast is going bad?
 

·
Steel Dreams
Joined
·
323 Posts
kleen56 said:
We have a debate going on with friends. What is the purpose of having a ballast resister on your cars wiring? Some said you have to have a ballast resister if your running points ignition. Others say you don't need a ballast at all and everything works fine. Any opinions? I'm talking about the square ceramic looking thing with a connection on both ends. Also, how do you know if the ballast is going bad?
Ballast resistors were used to drop 12 volts to 6 so a 6 volt coil could be used on a 12 volt system, and they were used on point systems.They cease to be used as the manufacturers switched to 12 volt coils and electronic ignition systems . Some had relays to supply 12 volts to the coil to start the engine and the relay would drop out of the start circuit when it started,others supplied 12 volts thru the starter solenoid then drop to 6 volts when the motor started.
So if a car has a ballast resistor with a 6 volt coil it is possible to change to a 12 volt coil with no resister as long as all of the other requirements of the system are met. ................make sure that it is wired right.

Hope this helps!
Kenny
Lost your job yet? Keep buying foreign.............
Oh ...to check to see if it is bad,use a volt/ohm meter on the ohm scale....no continuity....bad, high resistance ( more than a few hundred ohms) bad. Also with ignition in the start position ,a test light to coil side of resistor should light but wont tell you if it has high resistance.
Hope this helps!!
Kenny
 

·
Registered
Joined
·
129 Posts
On a points type system you need a ballast resistor, coil with a built in resistor or a resistor wire. You will burn your points out in short order. 55 to 57 chevys for example used the block and a 12v coil. Fords of that era used a 12v coil with an internal resistor built in. Later GM used a resistance wire built into the wiring harness. If you rewired your car and didn't put some type of resistor in you usually melted your points. Points are only designed to use 6v. I don't know why, but that is the way they were. The older GM cars used a starter solonid with an S and R on them. The S wire bypassed the resistor to give points 12v for a short time and then switched to the R wire for run thru the res. for 6v. If you changed starter and got the wires switched it would run when cranked and die when starter was released. They all used some type of res. until elect. dist were used and then they went to a full 12V or more to dist.
 

·
Hotrodders.com Moderator
Joined
·
6,391 Posts
The Ballast resistor is used to prolong point life. All points style ignition systems used them. They usually dropped the voltage down to about 9 volts when running. During craning the ballast was generally bypassed to give more voltage to the coil for a little hotter spark while cranking.
Most coils will take 14 volts and well beyond so there really is no limit there. A coil is just a form of transformer and basically the more you put in the more you get out. Its not exactly that simple but it is close. The same coil that will work on a standard ignition system will also work wth an MSD style system that uses 450V or so on the primary side.
 

·
Registered
Joined
·
800 Posts
Discussion Starter · #5 ·
Interesting? A friend is running 12V system and has one of those white ceramic looking resistors connected. He's running Mallory Supercoil, to a Mallory dual point distributor which was altered to a Pertronix electronic ignition. NO POINTS anymore. The truck runs fine, starts, doesn't miss,etc. Does he need the resister because of the Mallory supercoil? so it won't fry the Pertronix ignition? or should he remove the resister all together because he doesn't need it?
 

·
Hotrodders.com Moderator
Joined
·
6,391 Posts
kleen56 said:
Interesting? A friend is running 12V system and has one of those white ceramic looking resistors connected. He's running Mallory Supercoil, to a Mallory dual point distributor which was altered to a Pertronix electronic ignition. NO POINTS anymore. The truck runs fine, starts, doesn't miss,etc. Does he need the resister because of the Mallory supercoil? so it won't fry the Pertronix ignition? or should he remove the resister all together because he doesn't need it?
Most electronic systems require full battery voltage to operate at full efficiency. As always follow the manufactures recommendations.
The coil should not care, it is the points or module that are effected.
 

·
Registered
Joined
·
129 Posts
Been awhile since I've converted one but seems we eliminated the res. but best to check. We run a Malloy unilite dist. on our race car. Found out the hard way you have to use their special res. I think it's 9.4V or something. The ceramic one doesn't work and full voltage doesn't work either. At $90 dollars a pop for the bulb it was an expensive lesson. My kid bought it cheap but with no instructions. These really take care of all elect. problems and seem to have no rpm limit.
 
1 - 7 of 7 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top