I ran my C2 for just a few minutes & touched the ballast resistor on the firewall next to the Window wiper motor. Is it supposed to be HOT??
Thank you in advance for info, Don
Thank you in advance for info, Don
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Re: Ballast Resistor Hot??
Yes. That is why it has a ceramic insulator. -
Plus...
the heat profile is a function of electrical duty cycle. The worst case situation is when the engine isn't running, ignition is ON and points are closed. Then, the ballast is seeing 100% duty cycle and it'll get HOT as a pistol!Comment
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Re: Plus...
I had this very condition on a 65 about 35 years ago. Irealized the ignition was on when the coil exploded. Fortunatly, the ignition shielding trapped most of the flying particles of hot tar. Cleaning the inside of the shielding proved to be something of an adventure, however.Comment
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Re: Plus...
Jack:
Yes, very much like a toaster. If the circuit is closed, it gets very hot. When the toast is ready, it cools off.
JoeComment
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Re: Plus...
As the resistor gets hotter, its resistance increases, which reduces primary current. So, if you leave the key on and the points are closed, it should keep the coil from frying, but not always. That's why it's called a "ballast resistor".
It was common for engines with the 091 coil and 0.3 ohm ballast to fry their points, especially in cold winter weather when the ballast ran colder. Chevrolet wrote a TSB in 1963 recommending that the "normal" 1.8 ohm ballast be installed in these cars during the winter months and limited the 091 coil/0.3 ohm ballast to just SHP/FI engines as a running change in '63, then abandoned the low resistance ballast after 1964.
In past years we had some great discussions on this subject with the late Dale Pearman explaining how the ballast is an "analog computer".
This met with some guffaws, but Dale was right! It does function as an analog computer, albeit a crude one.
DukeComment
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One of the nice features...
of the Breakerless SE ignition system is it's intelligent power profile. While the solid-state ignition module doesn't 'get it' for having your car judged (judges can still detect the module despite its single wire hook-up by simply lifting the point adjust lift-window on the distributor cap and peaking inside), it's pretty neat for the daily driver car...
Basically, the Breakerless SE powers up when the ignition is turned ON then immediately goes into a 'sleep' mode where it turns OFF primary side ignition current leaving the ballast and coil primary circuits 'cold'. When you key the starter, the ignition module detects a wave train of pulses from the Hall Effect trigger mounted in the distributor. Something like four consecutive pulses cause the ignition module to power-up and fire the plugs.
System works similarly in reverse... The absense of something like 12-consecutive distributor pulses tells the ignition module the engine has been turned off and it automatically enters 'sleep mode' to squelch primary ignition current and thwart 'cooking' your ballast + coil.Comment
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