So i converted my chevy truck to 12 volt. I started and ran it without a ballast resistor. It ran fine. Then someone told me i needed a ballast resistor. So i installed one in the coil wire but when switched on the resistor started to smoke. The truck will not turn on with the resistor. I took the resistor off and it ran fine. Why is it that it smoked?
new ballast resistors will smoke a bit when they are new why your truck won't run with one installed is a good question...you need to tell us more about what you have , how it is set up , what parts/motor/ignition/coil etc and how it is wired
Well, they always smoked when they were new, fresh out of the box for a few minutes.. When you say you installed it in the coil wire,,,, Which wire ? The coil positive, the coil negative, or the coil high voltage wire ?? Before anybody flames on this question believe me, I have seen much , much worse !! LOL.... The resistor needs to be installed in the coil positive wire. Dave
Well i did a basic conversion. I have a 235 chevy. I still kept my floor starter. Installed a 1 wire alternator, new 12 volt coil, installed the voltage reducer to the fuel guage, got rid of the voltage converter because the 1 wire has one inside. Replaced all bulbs and headlights to 12 volt. Installed the ballast resistor in the wire going to the positive of the coil. My coil only has 2 wire hookups. Positive and negative. Negative going to the distributor and positive to ignition. When i turn the key to get ready to start it, it smokes.
seams like you have it wired right. if your points are closed when you turn your ignition switch to the on position it completes the circuit..so there is current flowing through the resistor. as already said , they will smoke a bit when new as for not starting...do you have that wire coming from the R terminal of the starter going to the + side of the coil? that gives full 12 volt power to the coil during starting
Also- Ballast Resistor: This is an electrical resistor that is switched in and out of the supply voltage to the ignition coil. The ballast resistor lowers voltage after the engine is started to reduce wear on ignition components. It also makes the engine much easier to start by effectively doubling the voltage provided to the ignition coil when the engine is being cranked. Not all car manufacturers used a ballast resistor in their ignition systems So you should check to see if yours does.
The fact that the car starts without the ballast means that it's wired correctly. An ignition system doesn't necessarily depend upon the resistor for starting, it just makes it operate better. If the car doesn't start with the ballast installed and its smoking, then it's probably either the wrong part or defective.
Thats what i figured because it starts perfect without the resistor. When i install it, it wont turn on and it smokes. Some one told me thay have had bad luck with ballast resistors but happened to be ok with the Mallory 700.
Some coils have a built in ballast resistor. I have never seen a new ballast resistor that didn't smoke initially. There is a coating on the resistor wire that is burning off. Most 12 volt systems use 12 volts to start and the voltage drops to about 8 volts when the ignition switch is in the run or on position. Joe
Doesn't the ballast resistor reduce 12 volts to 6volts going to the points. Anyhow, I was told that years ago by a "mechanic". He said that 12 volts would burn the points, therefore the resistor was needed.
i would take it off and check the voltage at the coil without it, some coils have an internal resistor (some will say you need a external resistor on the coil). also check the voltage with the resistor on first. or put a petronix kit in and run with 12v .
vertible59<SCRIPT type=text/javascript> vbmenu_register("postmenu_3834173", true); </SCRIPT> It drops it from 12 volts to about 8 volts,as you said to stop from burning the points!
I thought if you have a 12 volt coil a ballast resistor is not required unless the coil is designed for one, it should say on the coil. Effectively the coil is 6v and the starter drops the voltage to 6v when cranking and resistor drops it to 6v when running. I use a ballast resitor on 12v so I can run my 6v coil as I worry about the caperbility of 6v model A ignition systems on 12v. Regards Brendan
Do you have a good digital ohm meter that is accurate around 1-5 ohms? How many ohms does the ballast resistor have? The later stock 235 with 12V ignition coil required an external ballast resistor at 1.82 ohms. If your starter isn't wired for bypass and the ballast resistor has too high ohms, it will drop too much voltage for start-up. Napa has the correct resistor for 1955-62 235 cars & trucks. You can also order online, if no auto store in your town has it.
I had trouble with my roadster last year at Bonneville. I burned up two resistors before I finally found a chaffed wire on one side of the resistor so it was acting like a slow burn fuse and blowing out. I replaced the coil with one with the internal resistor. It is a cleaner looking setup.
Napa has a cheap one and a more expensive one.... Resistors Difference is probably country of manufacture. You can also find a starter switch that has the extra bypass terminal for wiring directly to the coil for extra amps just for starting.
Get a coil with internal resistor and forget the external ballast resistor. NAPA Echlin Pt # IC64, or Standard Ignition Pt # UC-15. This info is from Rundel's 12V converson guide.
Chevy 12 volt cars used a ballast resistor through 1957. The 1958 and later used resistance in the wire.
I could be wrong, but I think the internal condenser and the ballast resister are completely different animals. Some coils take a condenser that is usually bolted to the coil bracket and hooked to one of the coil terminals. A ballast resistor is spliced into the wire going to the coil. If you have trouble with the car starting with the ballast resistor, you might wire the car so that it starts on 12 volts and runs through the resistor when the starter disengages. All of the old point style 12 volt cars were hooked up this way from the factory. Larry T
If your coil needs a ballast and it won't start with a ballast then it means your wiring is not working properly. As noted there should be a 12V wire to bypass the ballast for cranking. If the ballast makes a no-start, it's because you're not getting 12v during crank and the 8v is not enough to fire the plugs at low cranking RPM. The easy answer to this whole deal is an internal ballast coil. I'm pretty sure they've got a transistorized dealie inside that bypasses the internal ballast at cranking speeds. The harder answer is figuring out why your cranking wire doesn't deliver 12v It may also be a situation where the coil is suspect because it's been run without a ballast for too long. Good luck!
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