Need Help with a Model A that’s Overcharging.

[crazycasey]

Don’t mind my previous post. My Model A seems to have started charging suddenly after I jumped the cutout terminals and motored the generator. BUT…now it’s overcharging. This A didn’t have any sort of external voltage regulator previously, and I rewired it without one, as, I had assumed (yes I know) that it must have not needed one. So, I’m seeing up too…probably 9 volts (old analog meter is hard to read amid all the shaking) and 10 amps now on the ammeter at speed. The car is freshly rewired, and all of the connections are sound. Positive ground battery connecting to the transmission. Separate ground cable from body to frame. Assuming (sorry) that the transmission mount is sufficient for grounding the engine to the frame.

I’m out of my depth when it comes to generators. Can anyone tell me if this is an original A gennie?



It sounds like from what I’ve researched that the Fun Projects cutout regulators aren’t being made anymore. Do I have an easy solution to regulate this generator down to 7-something volts on the generator!?

[Joe K]

I can't see the end-plate facing the firewall which will give clue as to whether this is a Model A gennie or from something later - or even "Autolite" which was a common replacement in the era.

If you remove the band nearest the firewall, you should see three brushes which contact the commutator. One of these should be more "moveable" than the other keeping in mind that each has a spring retainer to keep the carbon against the commutator. Two are fixed and the middle one between these two should be movable.

With a wooden stick you should be able to move this brush - which will affect your output voltage and charging rate directly.

Of course in the Model A era, a lot of batteries were sold after being overcharged and boiled dry (overcharging hydrolyzes the electrolyte essentially boiling it off as hydrogen and oxygen)

Most operators in the era attempted to find the "sweet spot" which is a point where charging was a little bit in excess, but could be controlled/consumed by operating the headlights. It was not uncommon in the era for drivers to drive with the headlights on - night or day.

I haven't looked since the passing of Tom Wesenberg to see what is available, but at least one manufacturer was offering a regulator which "looked" like the generator cut-out, mounted in that spot, but required some subtle wiring changes, primarily bringing a field wire out to the regulator.

Most later Ford generators had regulation done by flash control of the field coils - this is what the external regulator is designed to accomplish. Tom's version had the regulator inside the case IIRC - which is one thing which set it apart.

The generator is not complicated. Inspection of the wiring diagram will yield a lot, even where to tap into the field wiring to accomplish this change.



You see that the middle brush "feeds" the field. The VR would be placed "in" this circuit loop with the brush position placed "greater" than the field strength required. As you move the 3rd brush "away" from the grounded brush, the field voltage increases.

Elsewhere on the board someone asks about using a Tractor VR. There may be other options discussed. Check around - search terms "Voltage Regulator."

Here is one source for a "cutout appearing" VR made for the Model A Positive Ground.

https://gaslightauto.storesecured.co...5-r-detail.htm

Joe K

[crazycasey]

Originally Posted by Joe K

With a wooden stick you should be able to move this brush - which will affect your output voltage and charging rate directly.

Joe K

Joe,

Thank you!

So, it’s not necessarily “wrong” that there wasn’t an external voltage regulator installed on this thing previously? But adjusting the third brush to give, what, 7.2 volts, would be the standard operating procedure?

I should also state that I’m only putting out 6.8 volts or so at idle. If I turn the throttle lever up to a fast idle it jumps up to 7.5 volts or so. And then at cruising speed (I don’t have a tach, but I’d guess somewhere around 2,000-2,500 rpm it’s way up there at around 9 volts.

I feel dumb because I painstakingly terminated every wire, and enclosed it all in a woven loom. To go back and add an external voltage regulator now would be kind of a nightmare of its own.

The other issue that I have with this thing is that it has Nu-Rex “V8 points”, and the advance arm coming off the points plate contacts the plastic distributor body when the adjustment handle is only a couple of clicks down from the fully retarded position. So, if I set the timing per the book, fully retarded is about right, but I’m not getting nearly enough advancement range. Not sure how to remedy this, other than fabbing a longer linkage bar to allow full movement of the points plate…or bending things. I guess I could also clearance the distributor body to allow more adjustment.

[ndnchf]

Here is a short video I made showing how to adjust output with the adjustable 3rd brush.

https://youtu.be/PL94VX3GIq8?si=It-URParpCxqBY3I

[Bruce of MN]

Some of these issues could be cured by using stock points, linkages, etc.

Low voltage at idle that increases with revs is completely normal.

Do you have the Les Andrews red book for reference?

[crazycasey]

Sponsored Links (Register now to hide all advertisements)

Originally Posted by ndnchf

Here is a short video I made showing how to adjust output with the adjustable 3rd brush.

https://youtu.be/PL94VX3GIq8?si=It-URParpCxqBY3I

Thank you Steve. I actually watched that right after I saw Joe’s post. It comes up when you Google “Model A Third Brush Adjustment” or something along those lines anyway. You made that make sense. I have a question for you though. For those of us without a fancy test bench, what engine speed do we want to set the output at? If I’m aiming for 5 Amps, say, is that at idle, or at speed, or somewhere in between? Or is the Amp output less speed dependent than the voltage seems to be?

[crazycasey]

Originally Posted by Bruce of MN

Some of these issues could be cured by using stock points, linkages, etc.

Thanks Bruce, I pretty much agree. I’d like to make it work with what’s there, but perhaps that’s a too-tall order. So much of the Model A stuff I’ve purchased in the past (mainly body panels and things like latches, etc) has left so much to be desired in terms of quality and fit, that I’ve been unsure of where to even attempt to source all of the original type distributor parts for this.

The points plate that’s in the distributor now is a Nu-rex, and I reached out to them to ask about the advance arm hitting the distributor body. They make no mention of that on their website. I have read a couple of other posts that suggest that “modern” points are “in the wrong place”, but nobody really goes into detail on how they are so, or what they did to correct it.

[Kurt in NJ]

With the 3 brush generator the battery is the voltage regulator, the third brush only controls the amperage,
The amperage setting needs to be adjusted to your use, higher voltage can be because of a battery that doesn’t like to be charged and bad connections between the generator and battery.
Looks like a later production generator,33-34 style, is there a second wire coming out and grounded to the other side cutout screw?
My charging rate is set at 14 amps, many here will say that it is too high, but it suits my driving use, over 50% night, parades at idle, short trips, if I was to go daylight touring on long trips I would either cut back the charge rate or be lazy and turn on the headlights

Original production dist caps had a wider opening than later production caps that were also for the model b, there was a step in the opening that was larger and gave a place to file the opening to so it would fit either car

[ndnchf]

Set the 3rd brush at around 1200-1500 rpm.

[crazycasey]

Originally Posted by Kurt in NJ

higher voltage can be because of a battery that doesn’t like to be charged and bad connections between the generator and battery.

I had read that in another post. The battery and every wire in the system are all brand new. The generator has cleanly terminated 10ga (way overkill) all the way up to the ammeter and back out to the solenoid, which has brand new 2ga down to the battery. And every ground wire was sanded to shiny metal before attaching. The only ground in question that wasn’t addressed was the one the generator physically gets through it’s mounting to the engine.

Originally Posted by Kurt in NJ

Looks like a later production generator,33-34 style, is there a second wire coming out and grounded to the other side cutout screw?

I’ll have to take another look, actually. I believe there’s only the one wire you see in the picture, and of course my wire to the ammeter.

Originally Posted by ndnchf

Set the 3rd brush at around 1200-1500 rpm.

Thank you!

[Joe K]

Set the 3rd brush at around 1200-1500 rpm.

Plus 1. This being an "average" Model A engine speed in service around town.

You'll have higher speeds for short periods (like in shifting up through the gears or going on a highway) and you'll have lower speeds (like idling at a light or stop) but if I were to name an average speed I would guess around 1500. (2200 - 2500 is about the usual "top end" for the Model A motor in service.)

A VR gets rid of the issue completely - but that depends on how you take your pleasure in driving the Model A.

At least part of my pleasure is in the "differences" seen by others in my driving.

"Do you know you left your headlights on? Why do you run them during the day?" (Battery input-output balance)

"Why do you have a yellow glove on your left hand?" (Model A turn signals)

"I don't see a starter crank." (Under the seat.)

"Do you have seat belts" (Yes although not original.)

Setting yourself apart CAN be part of the fun.

Joe K

[crazycasey]

I figured I’d share these pictures to illustrate what I mean when I say that the points plate contacts the distributor body before I can get very much advance via the lever. If anybody has any thoughts, I’m all ears. The only thing I can come up with is to cut out the slot on the body more to allow more advance.

[jrelliott]

When mentioning the speed to set the third brush, you neglected to say the amperage. I set mine to 8 Amps at 1200 to 1500 rpm. Do not run much at night and run the parking lights even during the day after running for a little while (about 2 miles) to bring the charging rate down to about 4 Amps. Overcharging will evaporate the electrolyte in the battery.
The fun projects regulator adjusts the voltage out of the generator going to the battery, lights, horn, etc. You set the amperage to 8 -10 Amps at mid rpm. Have not found one that regulates the field current depending on the output voltage like later generators with a mechanical regulator or a modern regulator like on alternators. If anyone knows of a regulator that works on controlling the field for 12V would be interested. Have been trying to come up with a design, but have had no luck.

[rotorwrench]

I don't recognize the rectangular can on the generator. OEM and later replacement types have a round can cut out relay or diode depending on manufacturer. It would be important to know what is inside that rectangular object. It could be a cut out relay, a big diode, or a voltage regulator.

[Bob C]

Since you have a two tooth steering box loosen the clamp at the bottom of the column tube and rotate it so you get full advance travel.

[crazycasey]

Originally Posted by Bob C

Since you have a two tooth steering box loosen the clamp at the bottom of the column tube and rotate it so you get full advance travel.

Thanks Bob! I just figured this out a few hours ago. I’ve got this A drivable now, but I think the rotor phasing is still a little bit off. It’s hard to know if the points are in the wrong place on this “modern” plate, or if there’s just so much wear in the distributor that it’s not landing where it should. Basically, at TDC the trailing edge of the rotor is lined up with the #1 tit at full retard, and I thought it was supposed to be phased to the leading edge, here. I can’t seem to give the motor anymore than about 9 o’ clock on the lever even at speed, or it starts cutting out. I really wish I had the original stuff to make a comparison; I think these “modern” points are causing me problems, and this distributor is REALLY sloppy.

Any recommendations on a good source for a rebuilt unit with good original parts in it?

[crazycasey]

Originally Posted by rotorwrench

I don't recognize the rectangular can on the generator. OEM and later replacement types have a round can cut out relay or diode depending on manufacturer. It would be important to know what is inside that rectangular object. It could be a cut out relay, a big diode, or a voltage regulator.

Under the box is black epoxy…

Originally Posted by ndnchf

…

I did pull the rear band on the generator, and it IS a 3 brush unit. It was adjusted almost all the way down, and I readjusted it almost all the way up, so that I’ve got 5 Amps now instead of the 12 or so I had before. I have not re-checked the voltage. Thanks for that tip, Steve! Your video made it easy!

[rotorwrench]

I finally found a "universal " cutout at the Brillman Company that looks like that. It is a diode type unit but is made more for odd generators and tractor generators. The generator may be from a model B Ford. As was previously mentioned, the later generators had wires to connect the cutout. The model As were made in more than a few configurations. They had a screw terminal with insulator bushings instead of wires. That one could be set up with a screw type terminal if the exit hole in the case is the right size.

Ford mechanics used an ampere meter set in line with the output terminal on the OEM round type cutout relays to set the output amperage. They would set them for daytime charge rate initially at around 5 or 6 amps while idling. The output voltage will vary depending on battery condition and output amperage. I wouldn't use a voltmeter to set the output. Just make sure to maintain good tight and clean wiring connections. Make sure that wiring in the dash panel doesn't short out on anything. It's a tight fit in there and in the terminal box.

[crazycasey]

Guys. My head hurts. I had this A running flawlessly yesterday, and I go out to fire it up today (VERY COLD DAY), and it fires off, runs a bit, and then dies, like somebody cut the ignition. I try to fire it up again, and it’s just dead. So, I go through all the usual stuff; clean and gap the plugs, check the points gap, check the timing again, etc.

I check for spark by disconnecting one of the plug leads moving it a bit away from the post on the cap, and cranking the motor over, and I have a nice bright spark, AND the motor tries to fire…

So I disconnect ALL the plug leads, move them just off their posts, and crank the motor over, and it FIRES RIGHT UP! It’s actually running smoother than it ever has, all four cylinders arcing from the distributor to their respective plug leads.

So, thinking this has to be a fluke, I reconnect everything, and try again, and it’s totally dead. So, I disconnect the leads again, and it fires right up. I’ve got a video if you don’t believe me.

So, what the heck does this mean!? What part has gone bad on me since yesterday!?

PS-I did test the coil, and I have 1.4 ohms primary and 7.8k ohms secondary.

[crazycasey]

https://youtube.com/shorts/DBd3BIKYl...Ranez47m-C_p-p