ELECTRICAL GREMLINS [OVERCHARGING 440-3]

[freedgguccii]

Hey! My first post here, I'm glad to be apart of such a cool community.

I recently picked up a 1972 Starcraft Starcruiser Motorhome, its powerplant is a 440-3. I'm having some interesting electrical demons.

I'm having a severe overcharge, on start it slowly climbs to 14...15....16 and beyond volts, under load its 17+

Here's what replaced:
- 2 Voltage Regulators [AutoZone VR and OEM Mopar from Summit] originally came with a WELLS VR
- New VR Connector
- New Ignition Coil
- New Ballast Resistor
- New Ignition Module
- New Distributor Cap + Rotor
- New Battery
- Came with a newer alternator [Duralast DL7014 with Dual Field Wires]
- New Alternator Belt
- Cleaned/Sanded every single ground + Sanded the back of VR to bare metal

What I've Tried:
- Disconnecting VR plug, still overcharged
- Disconnecting the Green Field Wire, still overcharged
- Disconnected the Blue Field Wire + VR , did not charge at all, stayed at 12.2-12.4
- Disconnected the Blue Field Wire, did not charge at all, stayed at 12.2-12.4
- Disconnected both Blue/Green Field Wires but left VR plugged in, did not charge at all, stayed at 12.2-12.4
- Disconnecting Blue Wire WHILE running [not the best idea but was desperate] gave me spark, quit charging after unplugged

There's probably more that I have done BUT those are the major things, I'm stuck! Any insight is great, thank you all so much.

 

[67Dart273]

Thanks for the details, here is the most likely suspect

First, a bit about "how these work". The isolated field alternator brings the field connections out to the two terminals. They are electrically interchangeable. When you turn the key to "run" the switch sends 12V to one field terminal, and to the VR, WHICH MUST BE GROUNDED

The VR sort of "controls the ground" on the green wire which hooks to the remaining field

Since you disconnected the green field wire, this means that field terminal is grounded, and SHOULD NOT BE.

You need to remove the alternator and inspect the brushes/ brush holders for improper assembly, breakage, or missing insulators.

THIS IS A COMMON problem, as these alternators are commonly sold as replacements for the older 69/ earlier vehicles which HAD only one field, and so some of them come boxed with one of the two fields grounded. Also some of them come improperly assembled

CAVEAT. You lucked out!!! If you had accidently connected the blue field wire to where the green is, you may have burned up some wiring, as THAT CIRCUIT IS NOT fused.

 

[Dana67Dart]

Disconnecting the Green Field Wire, still overcharged

This statement speaks volumes.

As previously mentioned the green wire provides a variable ground to one of the two field terminals on the alternator.

If that wire is grounded it will cause an overcharge.

The fact that you disconnected it and still had over charging points to the terminal on the alt being grounded as 67dart273 mentioned.

If you disconnect both field wires and measure resistance to the case of the alt I suspect you will find one with 0 to 0.5 ohm resistance and the other something greater than 2 ohms

 

[freedgguccii]

Thanks for the details, here is the most likely suspect

First, a bit about "how these work". The isolated field alternator brings the field connections out to the two terminals. They are electrically interchangeable. When you turn the key to "run" the switch sends 12V to one field terminal, and to the VR, WHICH MUST BE GROUNDED

The VR sort of "controls the ground" on the green wire which hooks to the remaining field

Since you disconnected the green field wire, this means that field terminal is grounded, and SHOULD NOT BE.

You need to remove the alternator and inspect the brushes/ brush holders for improper assembly, breakage, or missing insulators.

THIS IS A COMMON problem, as these alternators are commonly sold as replacements for the older 69/ earlier vehicles which HAD only one field, and so some of them come boxed with one of the two fields grounded. Also some of them come improperly assembled

CAVEAT. You lucked out!!! If you had accidently connected the blue field wire to where the green is, you may have burned up some wiring, as THAT CIRCUIT IS NOT fused.

you're welcome! and thank you.

How could I tell if its improperly put together/grounded internally? Are there "tell tell' signs?

 

[freedgguccii]

This statement speaks volumes.

As previously mentioned the green wire provides a variable ground to one of the two field terminals on the alternator.

If that wire is grounded it will cause an overcharge.

The fact that you disconnected it and still had over charging points to the terminal on the alt being grounded as 67dart273 mentioned.

If you disconnect both field wires and measure resistance to the case of the alt I suspect you will find one with 0 to 0.5 ohm resistance and the other something greater than 2 ohms

I had a feeling its weird! I'll take a look at the resistance as well, what makes it worse is I believe its been overcharging its whole life!

 

[Dana67Dart]

what makes it worse is I believe its been overcharging its whole life

If it was the radio, fan motors, coil etc would be fried every few weeks.

I googled the alternator you listed and it is a 1 field wire alternator.

This is the photo they show on the website ( red terminal is grounded)

This is most likely what your alternator looks like..

round back alternator cores are in short supply so rebuilders internally ground one of the field terminals of a square back alt.

The blue is a grounded terminal.
the red arrow shows the CUT OFF terminal end ( your green wire is most likely attached to the stub that remains)

This is an alternative method of grounding a square back to function on a 1 field wire round back application. Note the connector and green ground wire.

 

[freedgguccii]

If it was the radio, fan motors, coil etc would be fried every few weeks.

I googled the alternator you listed and it is a 1 field wire alternator.

This is the photo they show on the website ( red terminal is grounded)
View attachment 1716170879

This is most likely what your alternator looks like..

round back alternator cores are in short supply so rebuilders internally ground one of the field terminals of a square back alt.

The blue is a grounded terminal.
the red arrow shows the CUT OFF terminal end ( your green wire is most likely attached to the stub that remains)

View attachment 1716170877
This is an alternative method of grounding a square back to function on a 1 field wire round back application. Note the connector and green ground wire.

View attachment 1716170878

This is super insightful thank you so much, I am a little confused however [im super new to all of this]

So, if my issue is the GREEN wire being grounded out internally, how can I go about fixing that? It looks IDENETICAL to the 2nd alternator you sent with the blue circle. So I guess it is grounded out after all.

What would the next step be to fix this issue? Explained in super simple terms LOL

 

[Dana67Dart]

What would the next step be to fix this issue? Explained in super simple terms LOL

Easiest is to replace the alternator with one for a 72 car. Just make sure the pulley is about the same size and the same number of pulleys

You can buy the proper terminal and brush etc and swap it out. But it's more complicated, not a lot but more

 

[freedgguccii]

Would It matter if my motor is a 74? I know all of the 70+ charging systems are the same BUT I'm just curious.

But to sum it up... my alternator is fried pretty much?

 

[Dana67Dart]

Would It matter if my motor is a 74? I know all of the 70+ charging systems are the same BUT I'm just curious

You could ask for a 74.

I just said 72 you be sure you get a 2 field wire alternator

But to sum it up... my alternator is fried pretty much

Probably not.

But it will not work for your application.

It would work in a roughly 68 or 69 or earlier application where a 1 field wire alternator was called for.

The other thing you might run into is getting the correct amp rating for a motor home.

If you spec the StarCraft motorhome and it's year you might be better off.

 

[freedgguccii]

I see I see, so the simplest solution is to purchase a new dual field alternator...

Makes me wonder if I could take my current alternator and just make it a single wire setup?

 

[Dana67Dart]

Makes me wonder if I could take my current alternator and just make it a single wire setup

You could replace the voltage regulator with a single wire VR.

but you will have to cut and splice some wires, not hard BUT more complicated than putting the correct alternator in the vehicle.



This kit MIGHT have the parts you would need to convert your 1 field wire square back to a 2 field wire square back.

alt

 

[freedgguccii]

Understood! I'll get to shopping then, thank you so much for all of your insight. I'll keep you updated. Feel free to drop alternator recommendations as well!

 

[Dana67Dart]

On your alternator is there about a 3/4" gap around the center ( red) or is it more like 1/16" ( blue)

 

[freedgguccii]

It's just like that red one! Black 3/4 line going around

 

[67Dart273]

1...There is NO WAY I would drop back to a single wire VR.
2...Use an ohmeter to verify the field is isolated. The proper term IS NOT "dual field." The alternator does not have "dual" field(s). It has two field TERMINALS, and the proper term is "isolated field" as opposed to the 69/ earlier which having one field terminal, is "grounded field."

3...I would NOT assume your alternator is fried or unfixable. I would first see if it is returnable UNDER WARRANTY as defective, and if not see (as suggested above) if you can get the proper brush/ insulator hardware.

Once you identify the problem you will see it is a simple mechanical puzzle. lt is almost always a matter of incorrect brush hardware or missing insulator

The rebuilders are hacks. Terrible. This poor output from rebuilders has been going on since I sold parts IN THE SEVENTIES and EIGHTIES. Yeh. I'm old. 75

 

[Dana67Dart]

It's just like that red one! Black 3/4 line going around

That indicates it is not an "improved" version of the Square back alt.

So if you decide to replace the grounded terminal/ brush parts be sure you get parts for the correct style.


And by the way...

Your first post was so refreshing...

So many post start with "my (insert problem part here) doesn't work"

Then 10 more posts while all those trying to help drag info out of the poster.


You did your homework and posted all the info needed for a diagnosis in the first reply!

Great job!

 

[Mattax]

Just a few comments to add here.
If yoiu haven't looked at this yet, it may (I hope) clarify how the grounded field terminal and idolated field terminal systems differ.

Identifying Chrysler Alternators (1960-1976)

Roundback and Squareback refer to the style of housing. Roundback through model year 1969. Roundback for model years 1970-71 usually has a slightly different rear housing Squareback Revised Squareback Is most easily differentiated by the thin middle between the housings. Overall these...

www.forabodiesonly.com

The year of the engine is not important. The vehicle year (and sometimes model and options) remains the same with respect to wiring.
Because its a motorhome, it may have been wired differently that the cars and regular trucks. It would be good to know if it was equiped with a second battery. If so, then we should figure out how that was wired in. There's been a few discussions in the past here (FABO) regarding auxilery batteries and how they get recharged.

 

[pt70]

Nice camper. I've got good news and I've got bad news. Good news ---you can fix it. Bad news--- you've got to fix it.
Your Truck has the isolated field type system. It should have a blue wire [12 volt with ignition key on], connected to either alternator field prong; It should have a green wire [the variable ground from the voltage regulator] pushed into the other field prong. The voltage regulator should have a triangle shaped plug pushed into it.

You have the wrong alternator. The alternator shown in post 6 is a grounded field type, even though one of the prongs looks like an electrical connector, it is NOT. I believe you can convert it using the kit from post #12. The 'wide prong' terminal is grounded; causing the alternator to overcharge.

 

[freedgguccii]

That indicates it is not an "improved" version of the Square back alt.

So if you decide to replace the grounded terminal/ brush parts be sure you get parts for the correct style.


And by the way...

Your first post was so refreshing...

So many post start with "my (insert problem part here) doesn't work"

Then 10 more posts while all those trying to help drag info out of the poster.


You did your homework and posted all the info needed for a diagnosis in the first reply!

Great job!

I appreciate you greatly for your kindness and patience. I tried my best to make it easy to diagnose!

I do have one more question however, I was looking into replacements and saw these... how do you feel about these? I'd like to be able to tell if they're grounded or not and was hoping you could help!

https://www.napaonline.com/en/p/RAY2132022

https://www.napaonline.com/en/p/RAY2132024

Alternator - Remfd - Standard 45-50 A RAY 2132009 | Buy Online - NAPA Auto Parts

Alternator - Remfd - Standard 55-65 A RAY 2132012 | Buy Online - NAPA Auto Parts

I BELIEVE these are all similar, but I know you all could help me figure that out! I know NAPA may not be the most Ideal brand but it's in stock near me, and I'd love to see if it fixes all of my issues!

 

[Dana67Dart]

The photos show all 4 to be 2 field terminal alternators.

2 are the updated style with the thin center

The pulley diameters are comparable.

Do you need 2 groove or 1 groove
There is a slight offset difference between 1 groove and 2 groove.


Take an ohm meter to the store and check resistance from each field terminal to the housing.

You meter should read "OL" or whatever it reads when the leads are not touching any thing

 

[67Dart273]

I appreciate you greatly for your kindness and patience. I tried my best to make it easy to diagnose!

I do have one more question however, I was looking into replacements and saw these... how do you feel about these? I'd like to be able to tell if they're grounded or not and was hoping you could help!

https://www.napaonline.com/en/p/RAY2132022

https://www.napaonline.com/en/p/RAY2132024

Alternator - Remfd - Standard 45-50 A RAY 2132009 | Buy Online - NAPA Auto Parts

Alternator - Remfd - Standard 55-65 A RAY 2132012 | Buy Online - NAPA Auto Parts

I BELIEVE these are all similar, but I know you all could help me figure that out! I know NAPA may not be the most Ideal brand but it's in stock near me, and I'd love to see if it fixes all of my issues!

Why can't you fix what you have now? Maybe a better question is, can you post a clear close up of your brush holders, maybe we can see what it/ they need

 

[freedgguccii]

The photos show all 4 to be 2 field terminal alternators.

2 are the updated style with the thin center

The pulley diameters are comparable.

Do you need 2 groove or 1 groove
There is a slight offset difference between 1 groove and 2 groove.


Take an ohm meter to the store and check resistance from each field terminal to the housing.

You meter should read "OL" or whatever it reads when the leads are not touching any thing

Got it fixed! Turns out the last alternator was a one wire, the new one works great. It seems to have a slight howling sound to it however? But none the less its awesome. Thank you all so much!

 

[Dana67Dart]

Got it fixed! Turns out the last alternator was a one wire, the new one works great

Carefully calling an alternator a 1 wire as there is a type of alternator that is a 1 wire (it has an internal voltage regulator, no external field wires)

As 67dart273 pointed out

The proper names are:

Grounded field = 1 field terminal

Isolated field = 2 field terminals

1 wire = internally regulated, no external field terminals

Mattax's link in the post 18 does an awesome job at showing the various alternators used in our cars

 

[freedgguccii]

Correction: It was a grounded field.

I gotta learn my terms LOL