1937 Ammeter

[TonyM]

I have been trying to chase down some shorts in the headlight harness. But I have noticed something with the ammeter while working on the car.

When the on-off switch is placed in the "on" position there is a small drop in the ammeter, about couple needle widths. The arrow will be just below the center line. Very small movement. When the car is running the needle appears to be centered.

Is this drop during switch turn on normal operation? What is the ammeter supposed to do normally on turn on? Does it stay at the center or is it supposed to move?

Any help greatly appreciated.

[40cpe]

the ignition switch energizes the coil and points in the distributor. If the points are closed they will draw current. You don't want to let current run through them for any longer than necessary.

[TonyM]

Thanks for the reply. Okay--So are you saying the small ammeter drop is likely the result of the on-off switch being turned on and allowing the coil and distributor to be energized?

[TonyM]

Originally Posted by TonyM

Thanks for the reply. Okay--So are you saying the small ammeter drop is likely the result of the on-off switch being turned on and allowing the coil and distributor to be energized?

Can someone answer this?

Thanks.

TM

[40cpe]

Originally Posted by TonyM

Thanks for the reply. Okay--So are you saying the small ammeter drop is likely the result of the on-off switch being turned on and allowing the coil and distributor to be energized?

yes

[TonyM]

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Originally Posted by 40cpe

yes

Big Time Thanks 40 Coupe.

I am learning. Now I can go back and try to solve this.

[ford38v8]

Tony, you didn't ask, but you will discover this question next, so I'll answer first:
When you crank over your engine to start, you draw down the battery to the point that it will require a slight recharge. Your voltage regulator will kick in with the generator, which will show on your ammeter as the needle will move up, showing a heavy charge. Watch the needle then, as it settles back to a slight charge within about a ten mile drive.

[David J]

Watch the gauge { car not running } and turn the lights on and off . Same deal - just bigger current draw so more gauge movement .

[TonyM]

Thanks 40cpe and all who have helped me with my car, especially Alan and DavidJ. Thanks guys. TonyM.

[TonyM]

It seems that the generator is not charging the battery all the way or at all. I lose about 0.04 of a volt after a ten mile ride. I have some reference materials and the Ford Barn search function; I hope to solve this but I will need all the help I can get. Will try and find some trouble shooting information on this and begin trying to run down the problem. Just need to solve this last problem and the re-wire job will be completed. Thanks ahead of time. TM

[ford38v8]

Tony, I don't know what your point of reference is, (0.04 volt), but it seems that you may actually be describing what i told you is normal. Read my previous post again and see if that is not the case.

[TonyM]

Okay Alan. I had been reading the battery with a volt meter. I wanted to see if the battery was drawing down with the car just parked with the battery connected and I noticed this while taking numerous readings over time. The ammeter never goes above the center indices while driving or with high rpms. I am still trying to learn this stuff. I'll try and read up as much as I can on the subject. Thanks Alan.

[ford38v8]

Tony, a couple of questions...

Do you have a round cutout on top of your generator, or do you have a rectangular voltage regulator on the firewall?

After a 10 mile drive and with your ignition off, what is your battery voltage by your voltmeter at the battery terminals?

How old is your battery, and what type is it? (traditional lead/acid or Optima?)

OK, that was three questions. I'm no wizard with electrics, but maybe we can get a handle on this together.

[TonyM]

Alan, I have the rectangular voltage regulator on the firewall.

Yesterday afternoon, before I drove, the voltage at the battery with ignition off was 6.01 volts; after the ten mile ride the voltage at the battery was 5.98 volts.

Battery is Optima 6V purchased in August 2012.
The Generator appears to be the two-brush 81A-1000-D type.
I am going over to where the car is in a little while.

Alan, Thanks for all of the help. TonyM.

[koates]

Tony, I think the way you are using your voltmeter for battery readings to test your generator is not really best practice. Do it this way. Start your engine and let it idle. Connect your voltmeter, one end to ground and other lead on to left (looking at voltage reg.) side terminal marked "ARM". Rev up engine to about 1500 rpm and note volts reading which should be about 7.5 volts approx. If voltage is much lower than this do this next test. Remove field wire (center one) from reg and connect it over into the ARM terminal. Do the same voltage test with your meter again, reving up engine. Should get 7.5 volts or more. What this test does is bypass the voltage reg and current reg contacts inside the regulator and allow the generator to charge on its own with no control, ie flatout. Maybee get someone to watch you dash ammeter while you do these tests to see if it shows "CHARGE". If you get no ammeter charge and your voltage does not come up to 7.5 volts plus, the generator is probually faulty. Get back to me with the results of this test and dont get side tracked doing anything else just yet. I am presuming here that your generator to regulator wiring is all correct as per ford diagram including the regulator earthed properly where it mounts to the fire wall ??. Regards, Kevin.

[TonyM]

Thanks. I'll try it. Yes, new generator wires from generator to voltage regulator with ground on the firewall/regulator mount. I'll ask my old car mechanic buddy Mitch to come over to give me a hand. Thanks a lot for the help. TM

[ford38v8]

Tony, it looks like Koates is the wizard you need. Follow his advice, and like he said, don't get sidetracked on anything else till you get it done as he instructs.

[TonyM]

The generator is not putting out. Thanks all for the help. Will rebuild generator.

[ford38v8]

Tony, that figures. I had a girl friend like that once. I just replaced her with a good one and all smiles ever since.

[dean333]

Tony, Joe Serritella of Vintage Voltage from our Local Early V8 Ford Club can check out your generator and regulator on his machine. He gives free check-ups for club members. He checked out mine and thankfully they were both fine. He restored my starter after it went out last week.