Burning up coils

[nqkjw]

Swap to HEI.
The MP control boxes may have been state of the art in their day but their day was 40 yrs ago.
It's a very common mod here in Australia,as good as a 6AL,cheap and dead easy to do.
Use a Chrysler electronic distributor,12V coil,delete the orange or chrome box and ballast and bridge the ballast wires.
Use either a Bosch BIM024 module or a GM IM113.
All mine are on HEI

[Strawdawg]

I checked the voltage drop from the + battery terminal to the battery terminal  on the alternator and it was only .2 v at idle but when I rev the motor it went up between 1.4 and 1.8v. Should the voltage drop increase with increased RPM's?  I rechecked all of the grounds ground off paint so I'm sure my grounds are good. Any other ideas?  Thanks guys!

That suggests you have a bad connection in the loop that does not like to carry the load.  That will fool the regulator in my experience so that it is working harder to try to make up the voltage loss.

[Husker Cuda]

That suggests you have a bad connection in the loop that does not like to carry the load.  That will fool the regulator in my experience so that it is working harder to try to make up the voltage loss.

So were talking about checking voltage drop on the bulkhead connector and the Amp gauge?  Anything else?  Is the switch and the steering column connector part of this as well?
How about if I run a jumper wire from the Batt terminal on the Alt to the hot on the start relay, would that at least tell me if the charging circuit would work right if I get rid of the voltage drop in the loop?

[Strawdawg]

We may be, and we may not be.

The wire from the alternator stud goes thru the bulkhead connector onward to the ammeter, then the other side of the alternator comes back thru the bulk head connector to the solenoid and on to the battery. 

But, the alternator has a pair of field sensing wires on them that tell the alternator how hard to charge.  The dark blue wire goes both to the regulator on the firewall and also to the bulkhead connector and onward to the igntion switch.  This blue wire feeds several things.

As you had a pretty good drop going to the battery, you can start by rigging a jumper from the alternator stud to the positive side of the battery.  After you do this, check the voltage and see if it has come down to a more reasonable range such as 15v.  If it does, or does not, then go to the dark blue field wire and check the voltage on it.  If it is reading much lower than the voltage at the battery, try adding another jumper from the battery, temporarily, to this wire...it goes to the ballast resisitor as well so you can clip on there...this does not need to be a large gauge wire like the jumper from the post to the positive.

In my case, I had a voltage drop in this circuit as well as the the main feed off the alternator. 

[Husker Cuda]

We may be, and we may not be.

The wire from the alternator stud goes thru the bulkhead connector onward to the ammeter, then the other side of the alternator comes back thru the bulk head connector to the solenoid and on to the battery. 

But, the alternator has a pair of field sensing wires on them that tell the alternator how hard to charge.  The dark blue wire goes both to the regulator on the firewall and also to the bulkhead connector and onward to the igntion switch.  This blue wire feeds several things.

As you had a pretty good drop going to the battery, you can start by rigging a jumper from the alternator stud to the positive side of the battery.  After you do this, check the voltage and see if it has come down to a more reasonable range such as 15v.  If it does, or does not, then go to the dark blue field wire and check the voltage on it.  If it is reading much lower than the voltage at the battery, try adding another jumper from the battery, temporarily, to this wire...it goes to the ballast resisitor as well so you can clip on there...this does not need to be a large gauge wire like the jumper from the post to the positive.

In my case, I had a voltage drop in this circuit as well as the the main feed off the alternator.

Very good info Strawdawg!  I ran the jumper from the alt to the battery and it still ran up to 17V when I held the RPM's around 3,000 like driving down the road. So I pulled that jumper off and jumpered the blue wire from the ballast resistor to the battery and it charged like it should in the 13.5-14v range. Both the dash harness and engine harnesses are new so I'm guessing my problem is in my ignition switch which is about the only thing left in the circuit that is not new. I will order a new switch and try it to see if that cures my headache!  Thanks again Strawdawg! 

[Strawdawg]

Before you order the switch, you might check the voltages under the dash.  There are two connectors coming out of the dash.  The one with the big red wire is the one that handles the ignition.  The other connector handles turn signals and such.

I would check the voltage coming out of the connector going into the column on the big red wire.  It should be reading battery voltage.

Then I would look for the dark blue wire coming out of the connector and check the voltage on it on the connector side that connects to the one from the column....with the key on, they should both read about the same.  If the blue wire is reading lower, then the problem is either in the connectors, or in the switch.

Lotsa work to change the switch so I would try to narrow down the location of the problem a bit better

[Strawdawg]

After I got old, I learned that nothing beats a set of electrical diagrams and a good volt meter for trouble shooting and that checking voltage drop rather than resistance was far more reliable.   It's not easy but it makes things more logical if you understand the circuitry.

You may have the manual, but, if not, maybe this will help on the connectors.

[Husker Cuda]

Perfect. Thanks Steve. New switch will be here Saturday.

[Husker Cuda]

Strawdawg nailed it.  I hooked up my new ignition switch today at lunch and guess what!  It charges just like it is supposed to.  For all you guys that have over charging alternators read up and work with Strawdawg (Steve) if you can't figure it out from my post.  I would have never guessed that the ignition switch could cause the charging system to over charge at 16 - 17V and blow up coils!  Thanks again Steve!   

[Strawdawg]

Glad you fixed it! Should be good for another 40 years

Sent from my LG-H810 using Tapatalk

[HP_Cuda]

Double bonus!

I now know what all the feeds (Red/Yellow/Orange) are for!!! 

[Chryco Psycho]

 

[dodj]