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Strange charging issue 1940 buick


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Hi guys. 
 

normally while driving the amp meter needles was just right of the centre in the plus. When i turned on my lights it jumped to minus and directly to plus again and was steady the whole way.  
but suddenly the needles is very jumpy and restless. While driving also a lot of the time in the minus and i can see my headlights dim. So scared of running dry. Today i had the generator testen and was top notch. Then in the testing machine we hooked about the voltage regulator and all values were great. So cleaned the connector and added a extra ground and did a test today. But still the same issue. Where do i need to look now. Regulator is new btw. 

thanks for all the help

 

 

 

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I'm not very good at understanding the mysteries of electricity, but it looks to me like you have an intermittent short somewhere in your system.  Does your car still have the original wiring?  If so, there may be an exposed wire somewhere that is intermittently grounding as it rubs against a metal surface in the body or frame.  The old insulation on the original wiring basically turns to powder after many years and will flake off leaving large areas of wire exposed.  Somewhere under the dash is where this is likely happening, but it could also be under the hood or just about anywhere where there's a positive wire that could be rubbing against the metal of the frame or body (like to the headlights, parking lights, tail lights, etc.).   Hopefully, someone more electrically-minded than me can help you diagnose and find this problem.

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I have not experienced this in EVERY car with a generator, but in many of them I have, including my wife's 1956 Chrysler. When the battery is almost fully charged, it appears that some regulators can't quite manage very small current levels. Hence the bounce. After a long drive on the highway, the needle on her ammeter starts to bounce around like that. It stops if we turn on the headlights for a while and give the generator and regulator something to do. But when it's fully charged, it bounces.

 

A change in regulators may help, since I don't believe it's endemic to all of them (my '41, for instance, stays rock solid at 0 once it's charged). It might be something as simple as the type of spring steel used in the points or maybe some regulators are more sensitive to temperature than others, I don't know. But after checking for shorts as Neil suggests, try a different regulator and see what happens. New doesn't necessarily mean good.

 

Hope this helps.

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@neil morse i will check the wiring. It is indeed still the original wireharness

 

@Matt Harwood mine was also rock solid at 0 before. That’s why i started to see it as an issue. I know that new doesnt mean good but it was tested in a testing thing with all wires attched and all values were good. Only the output of the regulator was around 8volts. Turned it down to 7,4ish. 
 

reason i dont thrust the bounch is because the light dimmed while driving so know the battery is not fully charged. 
 

thanks

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27 minutes ago, Robby120113 said:

reason i dont thrust the bounch is because the light dimmed while driving so know the battery is not fully charged.

 

But did the lights only dim intermittently, at the same time that the needle bounced to negative?  If so, that tells me the battery may be fully charged, but there is a sudden discharge surge caused by a short that is overloading the system.

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2 minutes ago, neil morse said:

 

But did the lights only dim intermittently, at the same time that the needle bounced to negative?  If so, that tells me the battery may be fully charged, but there is a sudden discharge surge caused by a short that is overloading the system.

Thats a good question. Dont know at the moment. Maybe good point. Maybe recheck all the wiring under the dash?

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I think the answer to the question about the dim lights would be very helpful if you can figure that out.  Another question: do you experience the bouncing needle (and the dim lights) when the car is stationary, or only when it's moving?  If it's happening when it's stationary, that would seem to cut against my "short circuit" theory.  If it only happens when the car is moving, I think that supports the idea that a loose, exposed wire is intermittently brushing against the body or frame somewhere.

 

As far as checking under the dash, I think that's a good idea.  However, you will quickly find that it's very hard to get your head under there to get a good look -- the space is very narrow and getting it sufficiently illuminated is difficult.  I find that you can get a good start in examining the general state of the wiring by taking your cell phone camera (with flash) and taking as many photos as you can while pointing the camera lens up under the dash.  It's kind of a "trial and error" procedure, so it may take you a while to get good photos that are in focus.  But you may be able to see where there's an exposed wire.  Here's an example of what my car's wiring looked like when I first bought it.  (Looking at these photos is what made me immediately realize that I needed to put in a new wiring harness!)

 

IMG_1529.thumb.JPG.54735e79eb421b645e0506cafd2b05cd.JPG

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Dollar to a donut you will find a bad ground somewhere.  At the battery, perhaps, or have you checked there?  Where the ground cable connects to the engine?  You do have large cables!  00 or larger!  At the headlight ground to the body. The engine to body [ at the coolant sensor at the back of the head on the right side].      

 

  Ben

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One other possibility comes to mind.  I assume when the needle dips negative the headlights also dim a little.  Check the generator drive belt.  The reason is that headlights will dim whenever the generator output drops, for example driving along at night and then waiting at a red light at idle speed, the lights will dim.  If the belt is slipping every so often, the needle will move into the discharge zone and then move back to charge when the belt is not slipping.  Should be an easy check to do.

Joe

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It's always the battery. If there was a short you'd have smoke or fire. 

 

Time to take that old Montgomery Wards battery in and get an Optima gel yellow top.

 

I don't know where you live but this time of year batteries freeze and then they are worthless chunks of lead.

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1 hour ago, Joseph P. Indusi said:

One other possibility comes to mind.  I assume when the needle dips negative the headlights also dim a little.  Check the generator drive belt.  The reason is that headlights will dim whenever the generator output drops, for example driving along at night and then waiting at a red light at idle speed, the lights will dim.  If the belt is slipping every so often, the needle will move into the discharge zone and then move back to charge when the belt is not slipping.  Should be an easy check to do.

Joe

 

JP, he has installed an ALTENATOR.

 

  Ben

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51 minutes ago, neil morse said:

 

Wait, what?  Where did he say that?

 

It doesn't matter. He needs to take out that monster 4 inch by 20 inch tractor battery which was made for harvest season or culling weeds and can't stand winter temperatures, which probably needs distilled water or a new charge of sulfuric acid, and get a real car battery for it, Optima only 4 inches by 6 inches and holds twice the amp hours as that 100 pound dinosaur.

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18 hours ago, neil morse said:

I think the answer to the question about the dim lights would be very helpful if you can figure that out.  Another question: do you experience the bouncing needle (and the dim lights) when the car is stationary, or only when it's moving?  If it's happening when it's stationary, that would seem to cut against my "short circuit" theory.  If it only happens when the car is moving, I think that supports the idea that a loose, exposed wire is intermittently brushing against the body or frame somewhere.

 

As far as checking under the dash, I think that's a good idea.  However, you will quickly find that it's very hard to get your head under there to get a good look -- the space is very narrow and getting it sufficiently illuminated is difficult.  I find that you can get a good start in examining the general state of the wiring by taking your cell phone camera (with flash) and taking as many photos as you can while pointing the camera lens up under the dash.  It's kind of a "trial and error" procedure, so it may take you a while to get good photos that are in focus.  But you may be able to see where there's an exposed wire.  Here's an example of what my car's wiring looked like when I first bought it.  (Looking at these photos is what made me immediately realize that I needed to put in a new wiring harness!)

 

IMG_1529.thumb.JPG.54735e79eb421b645e0506cafd2b05cd.JPG

Neil, you may be on to something here. This is what my 70 year wiring looked like before I re-wired the car a few years ago. I had nightmares of the whole thing going up in smoke. 

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Ben made reference to a ground from engine to body that comes off the cable on the temperature gauge at the right rear corner of the engine block.  However, this ground was missing from my car when I bought it, and I had no electrical problems without it.  I didn't even know about it until I got a new temperature gauge and saw it on the cable.  I don't think it's essential -- it has a particular purpose, which I believe is to prevent the cable from heating up and giving an incorrect temperature gauge reading.  I think the entire body of the car is well grounded through the bolts that attach the body to the frame.  Just my two cents.

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23 minutes ago, kingrudy said:

This is what my 70 year wiring looked like before I re-wired the car a few years ago. I had nightmares of the whole thing going up in smoke. 

 

Yes, Mike, I had the same concerns.  The same day I took those photos I went out and bought a battery cut-off switch and installed it.  I never left the car in the garage after that without making sure I had disconnected the battery!

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I do not have this issue with my 40 Buick, but I did on my 87 Cadillac. 

The alternator was putting out too much voltage. Probably the internal

regulator. New alternator problem solved.

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FIrst a little background....

 

Mechanical voltage regulators regulate voltage by using mechanical points to switch a resistor in and out of the field circuit of the generator. The field circuit controls output, so that is a change from low charge (resistor in) to full charge (no resistor in). That is a major change and one you will definitely notice in the lights as it switches.

 

The switching should only occur when the whole system gets up to it's normal running voltage, indicating the battery is fully charged and the generator needs to cut way back. Normal voltage is something close to 7.5 volts at room temperature (regulators adjust up and down a little with temperature). The shop manual will have the correct value. The contacts are supposed to vibrate fast from full charge to low charge, making the flickering less noticeable. More on that in a minute.

 

Some more sophisticated regulators have another contact on the set of points doing the regulating. This one normally comes into play when you drive a long way with a charged battery and without much electrical load, no lights, heater, radio and so on. The system voltage will continue to raise as the battery gets really full of charge. When it gets high enough, this contact shorts out the field, shutting the generator completely off. This contact is also supposed to vibrate fast to make the flickering less noticeable.

 

It is impossible to completely get rid of the flickering.

 

I have noticed over the years that extra resistance in the generator wiring will cause the flickering to slow way down. This is almost always from lousy connections in the wiring. This resistance (from lousy connections) can be in the the field circuit or the charging circuit. Inspect all the connections carefully. The field circuit is just a wire from the regulator to the generator (and the ground, more on the ground in a minute). The charging circuit is from the generator to the regulator "gen" terminal, and then from the regulator "bat" terminal to the ammeter, and then from the ammeter back to the battery, whatever path it takes to get there. I don't have a 40 shop manual handy, but I'll bet it goes from the ammeter down to the starter terminal, and then back through the positive battery cable to the battery. All these connections much be good or the "high-low" or "on-off" action of the generator will be really slow and annoying.

 

There must be a good ground between the generator and the regulator, and also a good ground from the generator to the battery.

 

Some cars have a ground wire running from the generator case to a ring terminal under one of the regulator bolts. if your car does not have this, follow the path from the generator back to the regulator. The generator should have a good ground to the engine (paint where it mounts can interfere). In cases like this there should be a ground wire from the engine or transmission back to the body, since the regulator is mounted on the body.

 

The charging circuit ground will be the spot where the generator bolts to the block, and whatever else takes you back to the battery post. On some cars, this is the negative battery cable, from the engine or transmission back to the battery. On others, there may be a cable or strap from the engine/transmission to the frame, and a battery cable from the frame back to the battery.

 

Now with all that out of the way, here is what I would do.

 

1) With the battery disconnected, check and clean all the connections. Replace or resolder any terminals that have been hot or melting.

 

2) Check the system voltage at the battery. You can try with a digital meter (like one of the harbor freight giveaways). When you are having trouble, check the voltage with the engine revved up to something above idle. It should be about 7.5 volts or so. A charged battery by itself is 6.3 volts. If the voltage is 6.3 or lower, the charging system is not working. If it is above 6.3, the system might be trying to catch up after a start or something, but should come up eventually. Try with the lights on too. If the system will eventually come up to about 7.5, you probably aren't going to have any dead batteries. If the digital meter just locks up and wont work, you will need an old analog meter to check, but that bridge can be crossed later.

 

3) I noticed you said a new regulator. Reviews I have read of current production regulators have been 100% bad so far. Someone, possibly Beemon, noted in another thread that the new ones have no weight compared to old ones. Considering that the stuff inside that makes them work is mostly copper and steel, that is a bit worrying. If you have the old regulator, I would use it if it isn't completely smoked. It doesn't need to necessarily be a Delco-Remy. If it is a replacement from the old days, that is fine.

 

Hope you get it sorted out, keep us posted.

 

 

 

Edited by Bloo (see edit history)
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Posted (edited)

@Bloo thank you very much for that detailed description. With this i will take a nother look on all the wires. Especially the one from regulator to ammeter. I added an extra ground from the generator to the body of the regulator. When we tested it on the bench with my generator on a small engine all values were stable and nice. We noticed the output of the regulator was 8volts. So i brought it down to 7.4 orso. But from what i was told this is probably to low since the loss in the lenght of the wires the charge can be a bit too low now and i will put it back up to around 8volt again and then measure it at my battery thus time. 
 

i have an extra video from last night. I just wanted to see what it does. It starts right up but after a few seconds it started with the dipping in the charge. If you look in the bright parr t of the light you see its dipping together with dipping of the gauge. 
 

 

 

 

Edited by Robby120113 (see edit history)
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In looking at your under dash photo I can see that one portion of the wiring was replaced but they just used electrician tape as terminal insulation. wiring really needs replacement.  I would suggest 2 alternatives to the $1000 + solution.  

first is make your own.  You can buy the correct reproduction materials for about $300.  The only skills are patience and use of a soldering iron.  Remove your original harnesses and build a list of wire connectors, wire gauge, length of wires, and pattern and color of the wire needed.

 

A second alternative is to contact the Brillman Company, 540 477 4112 and discuss sending him your harnesses to be duplicated.  I have found his cost to be about 3/4 of the big name harness producers.  He is the go to company for the materials if you choose to build your own harnesses.

 

l am fortunate in that I only live about 35 miles from his shop near Mount Jackson Virginia. 

 

Bob Engle

 

 

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11 hours ago, Robert Engle said:

In looking at your under dash photo I can see that one portion of the wiring was replaced but they just used electrician tape as terminal insulation. wiring really needs replacement.  I would suggest 2 alternatives to the $1000 + solution.  

first is make your own.  You can buy the correct reproduction materials for about $300.  The only skills are patience and use of a soldering iron.  Remove your original harnesses and build a list of wire connectors, wire gauge, length of wires, and pattern and color of the wire needed.

 

 


Hi Robby,

if you need new wiring it is not difficult to duplicate. I did one for a 1940 Pontiac many years ago and did it over several evenings. They are very simple circuits.
 

First thing is to make it easy to get to things by removing things that are in the way. Next thing is to get some tags or tape or something that you can use to Mark the location of where you removed the wire from. You then should end up with several wiring bundle once everything is removed. Take some good photos of the connection points etc.and make a good drawing. The shop manual is a great source to verify what you find.

 

Then you can duplicate each wire one by one. I used later plastic coated wire, quite heavy gauge as I did not want voltage drop. I wasn’t fussed about colours as I kept a record of what went where. The shop manual has the colours if you wish to follow those. I made the wires a tad longer just in case, then shortened as required. 
 

Soldered all the connections to make sure they were solid, you could also check your work with a multimeter to make sure connections are good. I also added period style bakelite fuse holders to several of the circuits as a safety measure, labelling each fuse with the amperage and what it protected.

 

You can also use a period style cloth insulation tape to bind the harnesses together. And don’t forget to add some wires for turn signal and auxiliary lamps just in case.

 

You can buy a lot of wire and connectors for $1000.00. The satisfaction of doing it yourself and the peace of mind knowing the wiring is 100% is worth all of the effort.

 

Just my three bobs worth

Rodney 😀😀😀😀😀

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Ok guys. Problem is located. Solution not yet but will continue tomorrow. The problem sits in the part of the regulator. We hooked a amp meter to the generator, when the engine was idle the ammeter in my gauge was shaking and the ampere on the generator was flucttuating between 8-12amps. But when we put a finger on the circled part and helped the point to contact the gauges was perfect and the amps on the generator was 19amps. So burned or damaged contacts. So will take it apart and let you guys know. 

DF3FDF8C-DC54-4C00-81AC-2643068AA076.jpeg

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Regulator points are supposed to go on and off, actually vibrate. That's how they regulate.

 

I cannot see which relay is which from that angle. The three relays are 1) Cutout  2) Current regulator 3) Voltage regulator. I don't mean to imply any particular physical order, just that those are whats inside the box.

 

The cutout prevents the battery trying to run the generator like a motor when it isn't charging. It is set for some lower voltage than the charging rate. It snaps down whenever the system is charging. On some cars it might cut back out at slow idle. On others it might be snapped down whenever the engine is running.

 

The Current regulator exists because a 2-brush generator like yours has no inherent current limit. If the battery (or the accessories on the car) try to draw more current than the generator's rating, it would happily supply it or burn up trying, most likely the latter. If the battery were half discharged, right after the engine started, the battery might want to draw a whole bunch of current. You might be using the lights too. That's just one example of a time the generator might need protection from too much current. On a car with a well charged battery that starts easily, you won't see the current regulator doing much. The current regulator can sometimes be identified by sight, as it may be wound with really huge wire.

 

The voltage regulator is the one that does most of the regulating, as I described in my earlier post. The points stay closed (typically up) if the system voltage is down, like right after a start. As soon as the battery starts to get full (about 7.4 volts on most 6 volt cars) the relay pulls down enough to open the points, and un-shorts a resistor that is in the field (control) circuit. That causes the voltage to drop, the points close, voltage comes back up, points open, over and over. It should buzz. As I mentioned earlier, if it's slow, it is probably the fault of high-resistance (bad) connections in the wiring. When the system voltage gets high enough, battery fully charged, the points will stay open and the system will stay on low charge.

 

If there is a second set of points below, on a long drive with no lights, the system voltage will drift up above normal and the lower set of points will start buzzing as the system bounces between low charge and no charge.

 

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One thing Bloo forgot to mention...  Do not file or sand the points to clean!!!  Only use a solvent and a clean thick paper to drag between the points. The points on a mechanical regulator are very special alloys and if it is filed off the life expectancy is VERY short. Remember as the points "buzz" there is a small amount of arcing, which is normal, and these special metals keep things working for a long time...remove the metal, remove the long time.....

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@boois was the relay marked as field that we touched and the rapid moving of the needle stopped and the charge went up. I took it out again to have a look at the points. Ofcourse cables will be renewed also. 
 

 

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These things can be a royal pain to fix.  The part you point to is the voltage regulator. The center one with the heavy windings is the current regulator.  If the points are messed a bit you can carefully polish them with crocus cloth and finish by rubbing them with plain white paper. then spray with contact cleaner. They have to be perfectly smooth. then check the voltage again.  They are fussy enough that you will likely get a slight different reading once you screw the cover back on.  If you get it right it will likely be fine for a long time. Or it may send you in circles for a long time. 

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