[dpoltzer]

On my stock 1971 Formula 455, My ignition condenser went bad. I believe that is because I don't have a ballast resistor mounted to the coil that attaches to the + side of the coil. I can't seem to find a source for a new/correct ballast resistor for my application. Anyone know where I can get one? Thanks.

[77 Canamman]

GM used a resistance wire in the harness instead of a ballast resistor.

[johnta1]

Firebirds (or most Pontiacs I know of, don't have separate ballast resistors) use a higher resistance wire. The wire that comes from the firewall to the distributor is the 'resistor'.

On the capacitor, is it the one with the points inside the distributor?

[dpoltzer]

I also have a 1970 T/A that is very original. There is an ignition coil, mounting bracket that attaches to the intake manifold. Attached to this bracket is a small "ballast resistor" with a 3" long black wire that goes to the + side of the coil. This device looks very similar to a condenser (The one that mounts under the distributor cap to the points set). I was told by a mechanic that because I am missing this "ballast resistor", I am going to continue burning up my condenser due to excess voltage in the system. My brand new engine wiring harness was built by American Autowire in NJ that I have been very happy with over the years. I would think that this harness has the correct resistor wires built in to it. Now I am confused on why I lost my condensor that is under 200 miles old.?

[22687]

I believe what you're looking at may be to suppress ignition "static" for radio reception rather than a ballast resistor. As noted above GM used a measured resistance wire in the harness to feed the coil while the key was in the run position.

[johnta1]

Exactly.
That is really a capacitor for radio interference mainly.
The capacitor(condenser) under the cap IS needed.

[Formulabruce]

I agree, coil mounted condenser is for engine noise on am radio. There should be about 7-9 volts at the + wire with key on and not hooked to coil. On a HEI this is called the "pink" wire and is much thicker, and pink. On a HEI. 12+ volts is fed to the distributor. The coil mounted condenser can be identical to the internal condenser in a points distributor. You do not Need the coil mounted condenser, and no harm done to leave it of buy a quality condenser, and points. I have used "Marine" ignition parts, and the quality is better than what's usually sold. Blue streak makes them I believe.

[22687]

Has this happened to multiple condensers or just this one time? If it has only happened this once could it be just a random condenser that went bad? Sometimes the simple solution is the best place to start.

There are others on this board with lots more smarts and experience than me but I'll ask if your mechanic checked the voltage to the coil with the key in the run position and found full voltage rather than reduced before he told you that you were missing the resistor?

[OG68]

^^^^^. What they all said. Resistance wire drops voltage down to 8-10 VDC and prevents the points from burning from excess voltage.
The condenser mounted to the coil bracket is for radio static suppression. There may also be another condenser mounted to the voltage regulator which does the same thing.
The condenser inside the distributor prevents the points from arcing. The three condensers look the same but may have different values usually noted on the end of the condenser.

To check if you have a resistance wire remove the wire from the coil that comes from the firewall plug. Turn the key to "Run" and measure the voltage on the wire terminal you removed to a good engine ground. If you measure battery voltage (12-13 VDC) you do not have a resistor wire and need a ballast resistor. If the voltage is less than battery voltage (8-10 VDC) you do not need anything but a new condenser.

I buy NOS Delco points and condenser from Ebay. No Chinesium electrical parts on my cars.

[necdb3]

https://www.ebay.com/itm/Nos-Delco-R...gAAOSwpe1bRja8

I think this is what you're looking for.

[dpoltzer]

Wow, thanks for the great info guys. The condenser that went bad is maybe a year old and has about 200 miles on it. Maybe it was just a dud. I did replace it with a quality unit with a lifetime warranty so maybe It will last. I will check the voltage readings at the coil tomorrow night to see what I have there. Thanks again.