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08-14-2023, 08:22 AM | #21 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
The original car had the engine pans that electrically connected the engine to the frame. Most cars no longer have these. The ground connection to the transmission bolt is good but the standard practice now is also to run a ground from the battery to the frame somewhere. All the accessories such as the lights and horn are connected to the frame, so if there is not a good connection between the engine and frame then that could cause problems.
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A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
08-14-2023, 09:20 AM | #22 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
Everything you guys say is true, and worth doing at some point in the future after the car runs, but these things are NOT causing the problems that he initially reported that he needs to address.
He's blowing 30A fuses. There is a SHORT somewhere. It might be in the lighting system, the horn, the alternator, or just in the wiring harness somewhere. Systematic electrical troubleshooting will quickly narrow it down as to WHERE it is, and then he can focus on correcting the short. Shotgun approaches of "try this", "you need to do that" won't quickly find the problem and fix it; it can actually make things worse as you unintentionally break yet something else. After that he can mess around with improving grounds, adding wires, etc.
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Jim Cannon Former MAFCA Technical Director "Have a Model A day!" |
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08-15-2023, 07:48 AM | #23 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
I don't disagree with you, Jim. What I"m saying is that bad grounding can cause high voltage, which draws more current and blows lamps and fuses.
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08-15-2023, 04:32 PM | #24 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
Resistance makes heat. The more resistance the hotter it gets. The fuse, if properly sized for the conuctor wire, is designed to burn before the wire does. 6-volt system work best with the lowest resistance possible. This is why the conductor wire is larger than what 12-volt systems require.
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08-15-2023, 05:00 PM | #25 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
In post #3 I mentioned the possibility of a short and later on suggested disconnecting things and searching for a short with a multi meter. This seems like a very simple thing to me and probably most people on the forum. But it is not a simple thing to some people who don't have the experience with electrical systems. I have to keep reminding myself of this. Those people need someone with more experience to help and to explain how to do things in person.
I don't mean to be condescending or to degrade someone. It may be that with enough help on the forum the original poster can solve his problems. I am quite busy right now but if the problem does not get solved in a couple of weeks, I will drive down to his location to help in person.
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A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
08-15-2023, 09:11 PM | #26 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
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08-16-2023, 06:50 PM | #27 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
Set your multimeter to the DC voltage scale. If you do not have a multimeter you can buy one at a very low cost at any hardware or automotive parts store. Put the red lead on the alternator post and the black lead on any good ground point such as the alternator case. With the engine at a fast idle you can read the voltage. The alternator may need to be hooked up to the electrical system to read a voltage. If it is a 6 volt system the voltage when charging should be about 7 volts. If it is a 12 volt alternator it will be putting out about 14 volts when charging. Any other number indicates a problem with the alternator or the electrical system or the battery. If it is a 12 volt alternator on a 6 volt system it will try to bring the battery up to 14 volts so the voltage you will measure in this case might be 8, 9, 10, or move volts. Excessive voltage will damage the battery.
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A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 08-17-2023 at 06:26 AM. |
08-16-2023, 08:02 PM | #28 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
Traveler, Mr. Tom Endy has posted an article "Isolating an electrical fault: Quick and Easy!" at www.Santaanitaas.org. You can find it under the tech articles for Tom in the Electrical section pretty far down the list of articles.
It gives step by step instructions on isolating the problem.
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08-17-2023, 09:14 AM | #29 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
You may have trouble with using a modern (digital) multimeter on a Model A w/the engine running, caused by RFI from the ignition system. Analogue multimeters (old school) are immune to RFI.
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08-17-2023, 06:23 PM | #30 | |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
Quote:
You can run the engine with the lights off without the alternator being hooked up. You just run off of the energy stored in the battery. For a test. You can buy a 6 volt positive ground alternator from one of the Model A parts suppliers and install it. IIRC you confirmed already that the car is setup with the battery installed "positive ground". There is no telling why the alternator you have has failed internally.
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08-19-2023, 09:24 PM | #31 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
alright got a chance to check the output of alternator and the highest reading i got was -4.8 . I removed the wires on the back of it and ran the car for 30 minutes with no problems. unfortunately I had to learn the hard way today with the woody and the windshield brackets if the windshield closes fast the brackets with crack windshield so I've got more work to do in replacing it.
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08-19-2023, 10:09 PM | #32 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
Does anyone make bumpers for the windshield swing arms?
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08-20-2023, 02:10 PM | #33 | |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
Quote:
But it was fun hearing them fire-up, his kids were jumping up and down...That was the last I heard from him. And I'd do it again...
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Keith Shawnee OK '31 SW 160-B |
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08-20-2023, 04:39 PM | #34 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
Yes getting these old cars to run after sitting for years is exciting.
We finally got the coupe running yesterday and took it for a sunday drive just now. Great fun with the whole family. Now the more I drive them the longer the list gets. |
08-21-2023, 03:22 AM | #35 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
I never liked digital,analogue can show a fluctuation better up or down.
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08-25-2023, 11:08 PM | #36 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
I got a new altenator but its still running ammeter pinned at start then settles to 20 amps. I keep battery on trickle charger but the alternator still charges it right when i start it. This one wont idle like the other 2 either. Ive got it 2 clicks on the advance with the tester light but it stalls out with both levers up and sounds like its missing.
Last edited by TraVeler; 08-25-2023 at 11:10 PM. Reason: English failure |
08-26-2023, 07:47 AM | #37 | |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
Quote:
By systematically testing and changing one thing at a time, you can isolate the problem. Spark lever (left side) "up" is just for starting. Pull it half way down as soon as it starts. A bit more when you go to drive off. Throttle lever (right side) needs to be down a few clicks to start a cold engine and keep it running. After it warms up (about 5 minutes) you should be able to push it up all the way. It will miss a bit when cold with the throttle lever all the way up. If it is still missing when warmed up, it could be a dirty carburetor (from sitting), the GAV is set wrong, the carb idle mixture is set wrong, the spark plugs are dirty, a bad ignition condenser (can happen with just age), or the distributor point gap is incorrect. Check and change or adjust one thing at a time.
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Jim Cannon Former MAFCA Technical Director "Have a Model A day!" |
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08-26-2023, 08:48 AM | #38 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
Traveler, I'm having trouble identifying exactly where you are in a logical process of elimination. Here are some specific questions that will help me and others home in:
There are normally two or more wires connected at the alternator. One from the terminal box and one or more spliced together that lead to multiple accessories, mainly the lights and horn, etc. To initially test for problem location (continually charging at 20 amps), leave the accessories wire / wires off the alternator and have only the wire to the terminal box on the alternator. If the fuse or breaker does not pop when you're wired this way, start the engine and run it. If it pops quickly, before starting the car, report back to us. You've said that the engine runs pegged at first, then after some time, it settles back to 20 amps and continues to run indefinitely, as in you could drive the car, but then pops when revved to do so? Yes or No? If the answer is Yes, either the ammeter is faulty or there is a high resistance somewhere in the charging circuit. This could be one or a combination of multiple issues collectively: This could be a weak battery, too small sized cables, loose, dirty, broken wire strands hidden by the wire's shielding, or corroded connections anywhere in the charging circuit (ground or load side). The battery is the load. The process of isolating these fault/s is called voltage drop testing. DC Voltage drop testing cannot be done with an ohmmeter. Voltage testing requires that current must be flowing in the circuit being tested etc. Waiting for Traveler's reply. Sorry for the rehash Jim, Rotor, and others, it took me a long time to think through my post and get it typed in and edited.
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"It ain't what you know for certain that gets ya in trouble. It's what ya know for certain that just ain't so!" Last edited by Rob Doe; 08-26-2023 at 11:54 AM. |
08-26-2023, 10:31 AM | #39 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
alright here are the things I've done
1)removed the horn it wouldn't work not connected 2)new battery(shows green light on Genesis charger) 3)replaced alternator with new one 4)cleaned battery ground at battery hold down 5)adjusted timing with light and nurex results are the same(although distributor cam screw is getting harder and harder to loosen) |
08-26-2023, 09:00 PM | #40 |
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Re: Hello All Been lurkin for a few week ? about ammeter and alternator
Yea the 30 amp breaker is still tripping. The car was off and the breaker tripped twice. I don't think these cars were run very much for the past 10 years. I guess I'll be learning more about the electronics on these things.
out of the 3 cars, at least one is running well other than the water pump leaks and I have to keep tightening the large weep? nut on the shaft. |
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