Why is it necessary to use a ballast resistor with the mopar electronic ignition? As I understand it, the ballast resistor was used to prevent the points from frying by lowering the voltage.

Please advise

Thanks

The ballast resistor is so the coil doesn't fry......

The condensor is to protect the points from arcing and frying.


Originally the ballast resistor was used to lower the voltage so that the 6V coils could be used when they went to the 12V system.

If you use a 12V coil, you don't need the ballast resistor (points or electronic ignition)

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Not so. The balast resistor is a current limiting device. It actually is a temperature sensitive variable resistor. The more current that flows, the hotter it gets, and the higher the resistance. The higher the resistance the less current that flows. It is self regulating. With point ignition it was used to keep the coil and points from overheating at low rpm, or engine off with key on, if the points were closed. (The condenser is to prevent the points from arcing when they open.) At higher rpm, the points are closed for a shorter perion of time, so less average current flows, and there is less time for coil saturation, so the balast resister allows more voltage to the coil for better spark. It serves a similar purpose, with electronic ign. It limits the current flow thru the transister in the electronic module.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Charlie,
Please help. I'd like to do the GM HEI ignition change, and I've been to a good site with good info, but I'm older and rusty! I have a '87 Dodge Ram, lean-burn system, and I don't have one of the older ceramic style ballast resistors. I do have a rectangular unit on the fire-wall, epoxy filled, with a 2-3 pin push connector. Also, my ignition is aleady "electronic", why can't I use my existing distibutor? Is it "curved" wrong, or what. Thank you in advance!

Not Charlie, but I can answer your questions.

One, a HEI ignition does not use a ballast resistor, so you don't have to worry about those. You'll bypass the resistor anyway. Slant Six Dan had a post about how to install HEI.

The trouble with the Lean Burn ignition is not that it's curved wrong... it's that it doesn't have an advance curve at all! The usual cure is to replace the distributor with a conventional electronic distributor that does use an advance curve.

However, you can make a performance ignition work with a Lean Burn distributor. I intend to do this on my turbo slant six. If your electronics are working correctly, you can use the output from the Lean Burn computer to trigger an aftermarket ignition box such as an MSD-6. It's possible to make one trigger a HEI - conenct the G pin on the module to the Lean Burn's spark trigger output. Then run 12 volt to the same pin through a 1 kOhm resistor. Ground the W pin, and hook up the B and C pins as if you were doing a normal ignition install. I've never tried this, or even heard of anyone attempting to do this, but it should work in theory.

I'm planning to combine a Lean Burn distributor with a Megasquirt ECU to give me computer-controlled timing that I can program. The reason I'm doing this is so that I can have it retard the timing under boost.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

One of the main reasons for doing away with the lean burn computer, is because the the timing advance is not working at all or it is totally wrong "curve". Why would you want to use it to trigger the HEI module or MSD. The reason to convert to a "normal" electronic dist with either HEI or MSD, or Mopar Module, is to get away from the lean burn computer.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Ok so the ballast resistor is the two pronged thing on the firewall right?

So what the hell do you call the "voltage regulator" on the firewall with FIVE prongs... (in the process of getting off my lazy ass to get to o'reilly's to get one as a matter of fact)So itd be nice to go in there and tell them what i want and then get the hell out (O'rielly's is not the place i would like to spend my thursday's...)

Thanks
Dave

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1974 Plymouth Gold Duster

Are you refering to the "electronic ignition module"?

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Yes

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1974 Plymouth Gold Duster

A few years ago I wondered about the elec. ignition (1 ohm) vs point type (0.5 ohm cold) ballast resistors and got one of each and tested them from 0-8A.

The point type gets hot and increased resistance a lot (to roughly 2.5 ohm); the elec. type didn't change resistance. I don't know why Chrysler changed it for sure, but I suppose it was to avoid running the wires inside the ballast red hot and subsequent failures.