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Discussion Starter #1
Seems my electrical problems are not solved with my '67 yet.

The alternator output varies between 12.5 volts at idle and 12.99 volts at about 3000 RPM. I am measuring with a digital volt meter at the back of the alternator on the battery terminal.

I returned the alternator to the parts store where I bought it from and was told it is operating properly, although they did not tell me voltage output on their machine. Voltage regulator is new (may be the adjustable type), and the battery is new.

The parts store told me to see if there is current at the F terminal on the alternator when the key is on. With a test light, I found no current when key is off, current when key is on.

I recently cleaned all of my engine grounds. I am now at a loss. :confused:

Thanks for helping me out.

Rick
 

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It sounds like you have a externally regulated system and the regulator is not turning on. You should have about 13.5 to 14.2 volts at the battery. It may be a little low when idling but should go up tp full output when the engine is above about 1500rpm.

I'll try to provide a simplified explanation of how the externally regulated alternator and regulator work here. This explanation starts from a parked car with engine off state.

The brown #4 wire is connected through the light bulb to 12V whenever the key is in the ON position. The other end goes through a set of points in the regulator and then out the F terminal to the field winding in the alternator. So some current begins flowing in the field winding from this connection. The little bit of current flowing produces a weak magnet field in the alternator and also lights the bulb.

When you then start the car, the weak magnetic field from above begins rotating which makes the alternator producing a little bit of voltage. This voltage is fed from the alternator to the regulator on the white #2 wire. This wire connects to a coil in the regulator and turns on a contact when the voltage goes above 3.2V.

Once the contact turns on in the regulator the #3 and #4 terminals are connected together. Terminal #3 is battery power so this puts battery power on both sides of the bulb and turns it off. This means the brown #4 wire should go to +12V. Also, this connects the field terminal right to battery power but still going through the points.

When the battery voltage goes above a set level, the F terminal is disconnected from the battery power by the points I kept mentioning. Then the voltage drops and the points close again. This on-off cycling happens rapidly and is how the voltage gets regulated.

From the above (KOEO = key on engine off and KOER = key on engine running).
F terminal - KOEO = #4 slight voltage KOER = 9-12V typically
#2 terminal - KOEO = 0V KOER = >3.2V
#3 terminal - KOEO = 12V KOER = 12V
#4 terminal - KOEO = F slight voltage KOER = 12V

By 12V above I mean battery voltage, which may be 12V when engine is off but should be 14V when engine is running.

Check the brown #4 wire by grounding it at the regulator. When grounded the light should come on. If you don't have a light then skip this test. Test this with the connector off the regulator.

Jumper the blue wire F terminal to the battery right at the alternator connector. This should make it crank out 16+ volts. If it passes this test, jumper wire the brown wire (#4 of the regulator connector) to the same F terminal and you should be able to measure >3.2 volts on the other alternator terminal. If these tests pass, it is in your regulator or the wiring to the regulator.

Peter
 

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Discussion Starter #3
Thanks Peter!

Went outside tonight and this is what I found so far.

F terminal - KOEO = 5.70
#2 term KOEO = 0
#3 term KOEO = 12.29
#4 term KOEO = 5.05

Now here is where it gets weird.

F term - KOER = 6.15 to 6.20
#2 term - KOER = 6.61
#3 term - KOER = 12.90
#4 term - KOER = 12.95

I grounded the #4 brown wire to the regulator and the GEN light came on. Next I jumpered the blue F wire in regulator (there's a blue wire in F terminal of alternator also) to the battery terminal in the alternator and alt output was 19.6

I stopped there because it's very dark now. rolleyes:

Anyway, what should I do about the incorrect voltages at the F and #2 terminals at the voltage regulator?

FWIW - the old guy next door came over. He used to work on cars years ago. Anyway, while the engine was running, he removed the POS cable, pointed out the engine was still running, hooked it back up and said there is no problem here.

Tell me it isn't THAT easy. :confused:

Thanks again.

Rick
 

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The values that Peter stated are correct, according to the GM manual for a 1965 to 1971 Chevelle. If I were to guess, it may be that your Regulator is not set correctly. Here is some additional info from a GM Manual.
Chevelle - Years 1965 to 1976.
Model Alt. 1100693,1100695,1100794

Regulator model 1119515

Field Relay
Air gap (inches) .015
Point Gap (inches) .030
Volts to close 2.3 - 3.7

Regulator
Air gap (inches) .067
Point gap .014
Volts 13.5 - 14.2

SS4speed.
 

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In the above posting, when I stated:

"If I were to guess, it may be that your Regulator is not set correctly."

I was refering to the low voltage that you are seeing, 12.99 volts. As far as the other incorrect voltages and if they have an effect on the 12.99 (I'll leave that to the experts).

SS4speed.
 

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Originally posted by RatMotor69:


FWIW - the old guy next door came over. He used to work on cars years ago. Anyway, while the engine was running, he removed the POS cable, pointed out the engine was still running, hooked it back up and said there is no problem here.

Tell me it isn't THAT easy. :confused:

Thanks again.

Rick
I'd tell the old guy not to do it to my car. That old trick has been discussed here before. Used by people who don't know any better and it can make good parts bad, says this old guy.
 

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Discussion Starter #7
Thanks guys.

So should I remove the cover on the regulator to adjust the contacts? I've never done this before. How do I adjust the contacts?

I'd tell the old guy not to do it to my car. That old trick has been discussed here before. Used by people who don't know any better and it can make good parts bad, says this old guy.
I didn't think diagnosing this problem was that easy as that old trick, but I'm no expert when it comes to electrical.

Thanks for your help.
 

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Personally (my opinion) I don’t adjust regulators. If they don’t work right, I replace them. Saves time and problems later on. On my 64 I put in a solid state regulator. AutoZone sells the Wells VR715 solid state regulator for around $11.00. Disconnect the battery lead before installing these. Be sure to have a ground strap from its case to the radiator core support.
The old guy’s trick only showed that the alternator was putting out something. It didn’t show that it’s not putting out enough to charge the battery. Only a meter test will show this.
 

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The F terminal voltage seems a little low. The #2 terminal voltage is OK since it just needs to be above 3.2V and it is.

I'd have to assume that everything was working and then it just quit working right one day? If so, then something changed so you need to find the actual problem. Adjusting the regulator may not fix it because the problem is still there. And you do have a problem because 13V is not enough to properly charge the battery.

What I see is that the Field (energizing) relay is closing but the Regulating relay is not passing the voltage to the field. This makes me think the contact in the voltage regulating relay is dirty and not making contact. If you take the regulator apart and run fine sandpaper through the contacts I bet it starts working again. If this fixes it, the contacts on the regulator are worn out and it needs to be replaced. At least some of the regulators have a wire connecting terminal 4 to the regulating relay and this wire could also be broken.

If you want to try adjusting it, the relay/contacts with the double points is the voltage controlling one. What you have to do is bend the tab where the spring attaches until you get the voltage you're looking for. Since the voltage is low you want more tension on the spring. You can adjust it at either end of the spring and sometimes the fixed end is easier to adjust depending on the regulator design.

When you get it working, I would really like to know what voltage you read off of the F terminal while it's running. I don't have a car with an external regulator anymore to test and I really don't know for sure what it is. I know it will change with the load on the system though so maybe a measurement idling no loads and with the lights on at 1000rpm.

Peter
 

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Discussion Starter #10
When you get it working, I would really like to know what voltage you read off of the F terminal while it's running. I don't have a car with an external regulator anymore to test and I really don't know for sure what it is. I know it will change with the load on the system though so maybe a measurement idling no loads and with the lights on at 1000rpm.
Great news Peter! I adjusted the contact points inside the regulator and the alternator is charging.
(BTW - I bought the regulator new about 1 - 2 months ago and have never straightened this charging problem out till now). It was easy with ya'll's help!


Anyway, alternator output is now 13.6 - 16+ depending on RPM's.

However, the F terminal KOER is now 5.70 volts whereas it was 6.15 - 6.20 volts. No lights were on and there was no load on the charging system.

If they don’t work right, I replace them. Saves time and problems later on. On my 64 I put in a solid state regulator. AutoZone sells the Wells VR715 solid state regulator for around $11.00.
John, I took your advise and bought one of these, it was $12.06 with tax. I'm keeping it as insurance.

Do I get to close the book on this one yet? There's lots more to do to this Chevelle.

Thanks very much for everyones' help!

Rick
 

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**Edit**

Sorry my reply was probably somewhat offensive, edited, hope no one was offended.
 

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No, something is still wrong. You should have about 13.5 to 14.2 at the battery at any rpm. With the old external alternators, the output tends to drop at idle so you may not get full voltage at idle even without any loads but as the rpms go up it should charge to about 14.2V and no more.

The voltage rising to 16V is not good for the electrical system, especially the battery after it's been running for a while.

I still think you have a regulator problem.

Peter
 

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The other thing I just thought of is that you maybe went to far adjusting it. They're fairly touchy and you have to check the voltage at a raised rpm as you go. You need to run it at 1000-1500rpm and wait for the voltage to stabilize to know where you are. It may not hold that voltage at idle but that's just the way they are.

Personally, I'd play with the mechanical one for fun until it seems to work and then stick the electronic one on for normal use. The electronic regulator is more accurate.

Peter
 

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Discussion Starter #14
Sorry my reply was probably somewhat offensive, edited, hope no one was offended.
I'm not offended. I just want to fix the car.


I appreciate all the help. I've learned quite a bit by doing all of this and that's what it's all about.

I'll probably just install that Wells regulator I have now, but it was kinda fun adjusting that old style regulator.

I'll let ya'll know how it goes.

Rick
 

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Be sure to disconnect the battery before installing the regulator. Also the case must be grounded, either with a ground strap or though one of the feet with a bolt and nut.
Yeah, I've never had much luck years ago playing with them.
 

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Discussion Starter #16
Update:

The Wells voltage regulator is now installed, charging system maintains 14.66 - 14.67 volts, within the range printed on the regulator installation instructions.


The ground strap was reinstalled, but those rubber insulators on the core support are getting pretty worn out. I see Ground Up sells them.

I'd like to thank everyone who took the time to help me out.
I'm going cruisin' tomorrow!

But if something is still wrong, go ahead and rain on my parade. I can take it. :D
 

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Excellent, it sounds like it is now working.

As John posted about not having much luck it's probably because the mechanical regulator are touchy buggers and it's only usually because they're not working right that you're trying to adjust them. In any case, you're better off with the electronic one.

The dealer can still get the rubber insulators for you and they'd be cheaper than an aftermarket resto house. I don't have the part number but I got it from here. Just post for well nut part numbers in the resto or electrical forums and someone should reply. Or try at a few dealers and if you get a good parts guy he may be able to find them. They had them in stock here because something still uses them.

Peter
 

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Fancy name for the insulators, as Peter says, is Wellnuts. The dealer should have them but the aftermarket places sell them for around a dollar apiece.
 
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