Overcharging 68Dart...need some short fused help (pun intended:)

[capnswanny]

After replacing the terminal on the battery, my son and I started the car up and took a number of readings. It looks to me like it’s fixed now!?!
I think using the VR 106 may have been causing some problems, I should’ve done one thing at a time instead of applying multiple patches to the problem.
Here’s a picture of the engine bay with their original style VR installed now.

Here are the voltage readings I scrawled down with the engine running. Sorry for the crappy handwriting, I was in a hurry! ;)

Unless you see something out of place, I’m going to tidy up the wiring and go for a short drive tomorrow (with my AAA card) to see what happens!

Thanks Again for all your help!!
-Corey

 

[TT5.9mag]

Get rid of the bolt together positive battery terminal. Those things are junk and cause all kinds of problems.

 

[TT5.9mag]

You can quickly check cable to battery voltage drop also with your voltmeter. One probe on battery post directly and one probe on cable terminal. Should be less than .1 volt.

 

[capnswanny]

View attachment 1715744178 Get rid of the bolt together positive battery terminal. Those things are junk and cause all kinds of problems.

Thank you, I totally agree. This was a temporary solution to test it out.

When I cut the sealed style terminal off, I found that the smaller cable to the starter relay was badly corroded about 3 inches down the wire. The cable to the starter ain’t looking too red hot either.
Finding or building a new cable set is on my list.
I appreciate the feedback, thanks!

 

[Mattax]

You're certainly closer to a more robust setup.

That the system went to 15.5 Volts at 3000 rpm is still somewhat concerning. I don't know the time from and I don't know how fast the electromagenetic field breaks down - so maybe its OK maybe not.

The shop manual tests for the alternator output were at 1250 rpm.
When you get back and its warmed up, bring the engine up to 1250 and then do some voltage drop tests adding loads. In other words start with engine running, then add fans, heater blower, parking lights, headlights.

Current through coil ought to be difficult to measure, its on/off as the points close and open. 5 amps seems high.

edit, skip the heater blower til you get one.

 

[Mattax]

Looking down the road see if there is anyone in your area who fixes radiators.
Since you're not in a jam (because you've installed the aluminim) then get it fixed right. If it needs a new core or header, those are expensive.
If no one local can do it, or can get the parts, then call Bob at Glen-Ray Radiators. He'll fix your old one and replace any components that need it. Budget around 500. It may be less since yours would be a repair and the number I've giving you is ballpark for a custom built one.

Then you can sell the aluminum radiator and electric fan and recoupe some of the cost

 

[TT5.9mag]

Thank you, I totally agree. This was a temporary solution to test it out.

When I cut the sealed style terminal off, I found that the smaller cable to the starter relay was badly corroded about 3 inches down the wire. The cable to the starter ain’t looking too red hot either.
Finding or building a new cable set is on my list.
I appreciate the feedback, thanks!

Sometimes it’s easy to overlook the simple things. Do not ignore the battery cables. The corroded cables may be most of your voltage drop. The voltage at the vr sense will tell the tale before and after each “fix” you complete.

 

[capnswanny]

Sometimes it’s easy to overlook the simple things. Do not ignore the battery cables. The corroded cables may be most of your voltage drop. The voltage at the vr sense will tell the tale before and after each “fix” you complete.

Thank you, I won't ignore them.

 

[capnswanny]

You're certainly closer to a more robust setup.

That the system went to 15.5 Volts at 3000 rpm is still somewhat concerning. I don't know the time from and I don't know how fast the electromagenetic field breaks down - so maybe its OK maybe not.

The shop manual tests for the alternator output were at 1250 rpm.
When you get back and its warmed up, bring the engine up to 1250 and then do some voltage drop tests adding loads. In other words start with engine running, then add fans, heater blower, parking lights, headlights.

I will find that in my FSM and do some load testing @1250 RPM today...Thanks!

I do have a question if you don't mind...
-At ~2k RPM, Engine Temp 175F, and no load other than engine, I read ~15.6 across battery with no discernable voltage loss from Batt to VR and Batt to Alt. Does this mean VR is faulty?

Thank you!!

 

[Mattax]

-At ~2k RPM, Engine Temp 175F, and no load other than engine, I read ~15.6 across battery with no discernable voltage loss from Batt to VR and Batt to Alt. Does this mean VR is faulty?

Maybe yes. let me get a cup of tea and go over the wiring arrrangement.

 

[capnswanny]

Maybe yes. let me get a cup of tea and go over the wiring arrrangement.

Thanks!!

 

[Mattax]

Here's what I'd do.
First. Verify that 15.5 voltage difference the regulator is seeing is the same as the battery is seeing.

If it is, then pop the cover. Look at the points. Are they clean? Can you move the arm from the high current to the no current position? Once you know they are clean and moving OK, you can verify the resistance through the regulator in the three positions. Try it again and then adjust the setting as needed. I'm pretty sure the shop manual and the MTSC have the procedures.

 

[Mattax]

Illustrations from the MTSC linked earlier.
If the points are stuck in the upper position, current flows through with no resistance.

When the voltage is above the set point (lets call it 14.5 V) the regulator's electromagnetic is strong enough to pull the points to the low position. Current flows the parallel resistors and then takes the easiest path to ground.

The connection to ground is a fusible link. If its broken then current will flow through the rotor windings instead.
Same flow path as when the points are in the middle position.

So make sure the link from the lower point contact to the ground is good.

 

[capnswanny]

Illustrations from the MTSC linked earlier.
If the points are stuck in the upper position, current flows through with no resistance.
View attachment 1715744358

When the voltage is above the set point (lets call it 14.5 V) the regulator's electromagnetic is strong enough to pull the points to the low position. Current flows the parallel resistors and then takes the easiest path to ground.
View attachment 1715744359

If connection to ground is a fusible link. If its broken then current will flow through the rotor windings instead.
Same flow path as when the points are in the middle position.
View attachment 1715744360

So make sure the link from the lower point contact to the ground is good.

Awesome pictures, better than what I found in the Service Manual.
I'll check the armature and contacts and verify resistance through the VR in the 3 operating positions.

Thank You!!

 

[Mattax]

Adjusting regulator.

If the points and connections are OK you can use your home made test ammeter to do the two regulator checks in the MTSC.
A tachometer would be helpful, but even without this should get its ballpark correct.
There are two tests; one is to test high load situations, and the other is to test higher rpm, low load situations.
The first relates to the sping tension, the second (which may be your situation) relates to the air gap setting.

Often the book drawings can be a little confusing.
Lets just go over the set up drawing.

For illustration purposes the main junction is shown at the car's ammeter stud. We can alter that to show the welded juntion but functionally its the same.

The Voltmeter is connected between alternator output stud and ground.

The Test Ammeter is between the alternator output stud and the output wire's ring terminal.

If I understand correctly, on your car there now two additional wires at the alternator output terminal.
1. Feed to fan power.
2. Parallel main feed through the bulkhead.

In which case the test setup will be something like this.

You can use either the fan and/or the lights to bring the alternator output to 15 amps for the first test.

 

[Mattax]

Awesome pictures, better than what I found in the Service Manual.

Those are all from MTSC 66-11
The regulator tests start on this page Alternators and Regulators (Session 228) from the Master Technician's Service Conference

Here's the set up with some notes added.

Ignition wires in this case refer to the power coming from the run terminal on the key switch.

While the first test could be done with a carbon pile, for most people the way to add load will be to turn on lights and or heater fan.
Current from out of the alternator will then increase to match the demand. Volts at the alternator need to be very close to the volts at the regulator's ignition terminal or these tests are not valid. (I think you understand that but others seeing this post who have not read the thread or the booklet may not.)

 

[capnswanny]

I want to thank you all for your help with this problem, with your guidance I was able to get her charging right and my son and daughter drove her to school today….of course I followed, just in case

Here’s what I learned over the past week or so…I had changed the coil after the original had released its guts and I installed an aftermarket coil. The ballast resistor that came with the car was also bad (would start when bypassed but not when in-line), so I replaced it with the one called for. Well, the new coil had a 1.4 Ohm internal resistance and the stock ballast was 0.6-0.7 Ohms…I didn’t know this was a thing. I replaced the ballast resistor with a 1.4 Ohm for 2.8 total, I think this was why I had 5 Amps of draw at the coil. With the new ballast resistor, it was at about 3.5. Also, points were bad (pretty sure I know why), the contact on the arm had welded to the other contact.

I think that the VR-106 I ignorantly installed caused a lot of the overcharge with this alternator after I had: relay-bypassed the ignition to the VR, ran new wires at the alternator, positively grounded the VR base, and replaced battery terminals and associated wiring.
I did attempt to adjust the contacts on the NAPA VR-32 Mattax, but it was way outside my realm of patience, I attempted the load testing and bending the tab holding the spring (to adjust tension) but only succeeded in making things worse (poured some beer on that one). So, I contacted FBO and ordered their electronic VR-1, installed it, and now voltage regulates between 13.2 and 14.4. Ammeter looks good, voltage gauge looks good, and the battery is fully charged after a 30 minute drive.
I also ordered a new thermostatic switch for the fan (should be here tomorrow) that closes at 195 and opens at 185. I thought I was playing it safe with a 185-175, but even at 170 the fan never shuts off…..meaning that even running down the road at 60mph on a 50 degree day, the fan is constantly running….and loading my charging system!

I’m sure I’m not done yet, but this was a huge relief for me. When my son and I towed this car home after my dad passed away two years ago, his dream was to drive it to school before he graduated. We made it, with your help…Thank You!!!

-Corey

 

[TT5.9mag]

I want to thank you all for your help with this problem, with your guidance I was able to get her charging right and my son and daughter drove her to school today….of course I followed, just in case

Here’s what I learned over the past week or so…I had changed the coil after the original had released its guts and I installed an aftermarket coil. The ballast resistor that came with the car was also bad (would start when bypassed but not when in-line), so I replaced it with the one called for. Well, the new coil had a 1.4 Ohm internal resistance and the stock ballast was 0.6-0.7 Ohms…I didn’t know this was a thing. I replaced the ballast resistor with a 1.4 Ohm for 2.8 total, I think this was why I had 5 Amps of draw at the coil. With the new ballast resistor, it was at about 3.5. Also, points were bad (pretty sure I know why), the contact on the arm had welded to the other contact.

I think that the VR-106 I ignorantly installed caused a lot of the overcharge with this alternator after I had: relay-bypassed the ignition to the VR, ran new wires at the alternator, positively grounded the VR base, and replaced battery terminals and associated wiring.
I did attempt to adjust the contacts on the NAPA VR-32 Mattax, but it was way outside my realm of patience, I attempted the load testing and bending the tab holding the spring (to adjust tension) but only succeeded in making things worse (poured some beer on that one). So, I contacted FBO and ordered their electronic VR-1, installed it, and now voltage regulates between 13.2 and 14.4. Ammeter looks good, voltage gauge looks good, and the battery is fully charged after a 30 minute drive.
I also ordered a new thermostatic switch for the fan (should be here tomorrow) that closes at 195 and opens at 185. I thought I was playing it safe with a 185-175, but even at 170 the fan never shuts off…..meaning that even running down the road at 60mph on a 50 degree day, the fan is constantly running….and loading my charging system!

I’m sure I’m not done yet, but this was a huge relief for me. When my son and I towed this car home after my dad passed away two years ago, his dream was to drive it to school before he graduated. We made it, with your help…Thank You!!!

-Corey

View attachment 1715749297

This is very cool. Well done and glad you got it figured out. Some of my best memories are from high school in my dart. You’ve given your kids a chance to make memories that’ll last a lifetime.