Starts and runs with a FRIED ballast resistor

[CHL2T]

I recently acquired a 72 Dodge D200 beast of a truck........

It hasn't ran for over five years so to get it running,  I had to basically give it a tune up and clean the gas tank

Supposedly the old man I got it from (for free, long story...) said the 440 had been balanced, blueprinted, ported,  polished and completely built for major horsepower. He claims 500, but I think he may be a little off, hard to say as I have yet to drive it.... 

The good battery I installed, was being drained everytime I ran the truck and figuring it was the charging system,  I verified that there is only 12.5 at the alternator output.

When I was replacing the regulator with a good spare, I noticed the fried resistor

Anyway, with a fried resistor,  why would the truck still start and run fine?

I thought that any Mopar of this vintage will only start with the key in the start position and die in the run?

The only visible performance part to be seen is a "mallory" distributer, everything else is stock Mopar i.e. resistor, regulator, coil ect....

[MEK-Dangerfield]

Are you sure the fried resistor isn't for the windshield wipers?

[CHL2T]

Are you sure the fried resistor isn't for the windshield wipers?

LOL.....it's the ignition resistor.....

[72rtchallenger]

does the ballast just  look fried or have you checked with a meter ?

this link shows the correct ohms http://www.mymopar.com/index.php?pid=115

[dodj]

does the ballast just  look fried or have you checked with a meter ?

 They can look pretty crappy and still be fine electrically.

[sprecks]

If the resistor is really fried, there must be a jumper wire around it.

[dodj]

If the resistor is really fried, there must be a jumper wire around it.

Will have a short lived coil though...

[CHL2T]

The thing is completely wasted, the ceramic casing and the wound core material literally poured out the back as soon as I unbolted it.

With a little probing, I found the winding was still all there and intact so that would be the reason it kept running but sending 12+ to the coil.........

Still doesn't solve the charging issue though.....

Replaced alternator with know good one - no change (gonna full field it and check for proper operation, I know, shoulda done this first...)
Replaced Regulator with known good one - no change
Switched field wires around knowing that wasn't the problem - no change
Found bad bone, gonna replace tomorrow

Thanks guys 

[4Cruizn]

Voltage  regulator will cause it not to charge . .

[HP_Cuda]

The resistor is only there to bring down the voltage to the coil.
Since you have a Mallory distributor in it, it as well needs one unless it has a built in one.

Most times you are dropping 12V down to like 7.5V to 9V.

B

[72rtchallenger]

if you cant find any wiring problems then even new parts can be bad like the regulator or alternator as they dont build them like they use to 

[CHL2T]

I think I got it figgered out..... It seems that there wasn't a good enough ground on the regulator, there was a couple corroded connections and of course the bone.

I can start and run it and it seems to be charging  but when I remove the negative cable it will run for a second or two then die.... I think I still need to do some more ground examinations....
 
I have 13.5 out of the alternator but only 12.5 at the relay and battery when running
I'm going to do the ammeter bypass and see how that does

[72rtchallenger]

a bad ground does sound right,,these are big issues on the older cars , hope you got it traced down   

[dodj]

The resistor is only there to bring down the voltage to the distributor.

I think you meant coil.

[CHL2T]

Re checked the grounds, ran a wire from the alt to the relay and now all is well with full charge taking place