Ballast resister

[Zippy]

Can anyone help me understand why there is a ballast resister on my 73 Cuda which has factory electronic ignition? I've always been under the assumption that a ballast resister was used to reduce the current to the points which helped to keep them from burning.

 

[FLY'NFISH]

I have read that it is there to protect the coil and ECM even when running the electronic ignition. I believe the newer coils have the resistor inside in order to eliminate the firewall resistor. I'm still running mine regardless of the newer coil/ECM. Maybe someone could elaborate further.

 

[704406]

The resistor is to reduce the voltage to the coil. The coil runs at roughly 8-9 volts. If you run it at battery voltage it will burn out and leave you stranded. The resistor allows battery voltage to the coil for starting only that's what the extra wires are for.

 

[Zippy]

Thanks!!

 

[Mad Cuda]

Im replacing my OEM distributor with an MDS coil and distributor. The new distributor directions says to bypass the resistor to allow the full voltage to the MDS distributor.

 

[Don Gould]

Must be a R2R MSD distributor?

 

[Mad Cuda]

Its a Chrysler 383-400 Ready-to-Run MSD Distributor, Part #8386.

 

[Don Gould]

Then it does not use the ballast resistor.
Good luck with that distributor we won't touch them, in this business the last guy to touch it becomes responsible and we won't take any responsibility for MSD's Chinese imports and let MSD off the hook.

 

[Mad Cuda]

Im new at this and just trying to do my best to make my Mopar run smoother. I've only had the car a few months. Are you saying that I just made a $400 mistake? Others I've spoken to recommended I go with MSD Distributor. By the way, what is the recommended spark plug gap. Im going with NGK's. Thanks Don

 

[Don Gould]

MSD is all Made in China now. (Some in Mexico)
If you want it to run right you need a distributor that can be tuned to your engine specs.
You need an adjustable vac can MSD is is not adjustable and connected to constant manifold vacuum source.
1 year warranty and a high return rate... not very reliable.

MSD themselves hired a independent engineer and they discovered that wide gaps are NOT the best way to go and retracted their previous thinking and came up with a whole new set of perimeters, starting with "Whats the compression ratio" it was published in Gwen Johnson's "Good Ink" a industry news and information service. We have never used those ridiculous .050 or bigger plug gaps, they just stress the entire ignition system and burn up spark plug electrodes.

We never use Japanese plugs in our American Muscle cars, either AC Delco, Champion or (my favorite) Autolite. Most street cars will do fine with 032-035.

Look at the features and reliability of the HRR688 that we build right here in the good Ole USA before you start hacking your wire harness up.

 

[Mad Cuda]

A lot of great information. Boy do I have a lot to learn, and unfortunately, its an expensive and time consuming process. Im thinking I should take my car to a Mopar expert and have him guide me before I spend any more money. Thanks

 

[Don Gould]

Just did.......