| lightflyer1 | -- 02-20-2011 @ 11:28 AM |
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Friend has a 1936 Ford Coupe. Engine runs fine as long as the battery is kept charged manually. Original generator wasn't charging he told me. Checked with voltmeter and only shows battery voltage at battery. Pulled it off and swapped for another he had on hand (used). It didn't show a charge either. Sent the original in to be rebuilt. It came back and we installed it and a new script looking modern voltage cutoff unit. Only gets battery voltage at battery at high idle 1000 1500 rpm maybe. Changed cutoff to another he had on hand and no change. Doesn't seem that complicated as there are only two wires. One to battery side and one to armature side. Any advice on what to check next?
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| 37RAGTOPMAN | -- 02-20-2011 @ 2:54 PM |
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did you adjust the 3 rd brush, if not try that, if still does not charge Take the cutout off, dissconect the fan belt, carefully, run a 10 gauge or better junper wire from the negative terminal, this should be the hot side being the positive is ground, run the wire to the ARM wire going into the generator, it should spin,IT SHOULD MOTOR, BE REAL CAREFULL of the FAN, is there a new wiring harness in the car, how is the dash wiring, up though the amp gauge,??? all wiring termials tight and clean, did the generator work before, did he do anything different, were did that CUTOUT come from, boy that is wild, I never saw one of them., lets hear how you made out, so we can maybe add to this, the more info the easier it will be, 37RAGTOPMAN This message was edited by 37RAGTOPMAN on 2-20-11 @ 2:56 PM
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| Dolman | -- 02-20-2011 @ 2:57 PM |
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Suggestions: Verify that the generator is actually generating by disconnecting its wire from the cutout and measuring the voltage at the lug. Should be at least 7 volts. If no voltage, check to be sure the generator housing has a good ground. You can check the ground with an ohmmeter between the generator housing and the engine block. Should read zero ohms (be sure to zero the meter before taking the measurement). The generator's ground is through its housing and the mounting hardware. If the ground is good, your friend may have won the negative lottery. Crimp on connectors are always suspect to me. I've seen more than a few that gripped the wire insulation tightly but had a poor if any contact with the wire itself. Three bad ones on a brand new boat trailer. I solder mine and use shrink tubing. Disconnect the blue wire from the cutout and check its continuity from the lug back to the fuse block. If there is continuity, be sure it is connected to the correct side of the fuse. The correct side is the terminal that the yellow wire from the ammeter is connected to. Here, I am thinking of the possibility of a blown fuse. If the cutout is connected to the wrong side of the fuse and it is in fact open, the engine would run but lights would not. Comment on electrical connections: They have to be clean, clean, clean. The horn on my 34 pickup didn't work when I bought it. Troubleshooting the problem discovered that one of the connection screws had not been firmly tightened and all sorts of crud had crept in between the screw head, washer, and post. It had gone on long enough that just tightening the screw didn't get a honk. Cleaned every thing with emery cloth and solved the problem. Lightflyer1, that's the best I have to offer. I am still on a steep learning curve with my old Ford like many of the members of this forum. If the "old boys" have better ideas or want to correct me, that's ok. There are several of them that I would like to apprentice to. This message was edited by Dolman on 2-20-11 @ 3:00 PM
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| supereal | -- 02-20-2011 @ 3:53 PM |
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Lots of good advice. Be sure to check the battery, preferably under load. A bad cell will produce the problem you set out. It presents a high resistance to charging, and the cutout sees it as a fully charged battery. We check charging systems by placing a voltmeter across the battery poles. You should see about 7.2 volts in a healthy system. If not, backtrack with your voltmeter across each leg of the system until you find the culprit.
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| drkbp | -- 02-20-2011 @ 4:44 PM |
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lightflyer1, If you have not already solved your problem, Ragtop is correct, set the third brush. Loosen the nut/clamp on the third brush and move it in the direction of fan rotation and it will increase output. Tighten clamp and start engine. See if it increases amps on your dash instrument amp gage. To lower output, move third brush against the fan rotation. The third brush is under the cover you have clamped over the back end of the generator. I would put the cutout on. Turn on ignition. Amp will show a slight discharge. Turn ignition off and the amp gage should zero. If it does that, it may be that the cutout is just fine. When engine starts, if the amp gage goes to zero the cutout is not the problem yet. IF the amp gage jumps back and forth rapidly, bad cutout so get another one they are cheap. It's the same cutout switch Ford started using in 1919 all the way through V8's. About twenty years. Crank the car. Amp gage should go near zero when car starts. Fast idle should show positive charge (needle moves only slightly sometimes). If not enough for you, move third brush in fan rotation and remember to tighten third brush before starting. If it shows 4-5 amps on the gage on your dash, you are there in my opinion. Don't have the emergency brake on or the lights on while you are doing this. Any good alternator/generator shop can check your generator. Did a 6-volt generator month and half ago and did a 6-volt starter last week. Leo checked them while I stood at the counter. You can put a ammeter in the charging circuit at the generator and get a more correct reading. I do not think you have a two rate (F terminal) generator. They were on some cars with radios. Yours looks like mine. All this said, I take my 6-volt batteries out and give them a good charge about every six months. All my starter cars have six volt systems in them. Ken in Texas This message was edited by drkbp on 2-20-11 @ 4:47 PM
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| lightflyer1 | -- 02-20-2011 @ 5:55 PM |
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It isn't the third brush. Nothing changes with it in any position it is in. I will try the things mentioned here next pass at his house. Thanks! This message was edited by lightflyer1 on 2-21-11 @ 8:12 AM
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| lightflyer1 | -- 02-26-2011 @ 10:16 AM |
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Found lead to third brush with insulation wore off from rubbing. Fixed that. Ran engine and checked output from disconnected arm. wire and got 8 to 12 volts depending on engine speed. Battery side when arm wire reconnected still only reads 6.2 volts. Seems as though the generator is putting out but not getting through the cutout. Tried orignial NOS, solid state (2 versions). Car ran before and charged. Wiring checks to be good so far. I am assuming the B and A on the cutout stand for battry an armature. Moving third brush does nothing. Original ammeter shows slightly discharge but never moves as engine speed changes. This message was edited by lightflyer1 on 2-26-11 @ 10:21 AM
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| supereal | -- 02-26-2011 @ 10:31 AM |
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It is likely that the problem is either an open field or armature. The only reliable way to test an armature is with a tester called a "growler". By substitution, you have likely eliminated the cutoff. Unless the engine groundstrap is missing, or the circuit from the cutout to the battery is open or faulty, a rebuilt generator is probably the next step. The cost for a rebuilt is around $200, plus the old unit as a "core". The early (34-38) generators are getting scarce. I put a 6 volt alternator on my Model A when the generator quit at considerably less than a replacement generator.
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| lightflyer1 | -- 02-26-2011 @ 10:43 AM |
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Sitting here with two supposedly rebuilt generators, one local shop and the other repaired by service listed in Hemmings. Same results. This message was edited by lightflyer1 on 2-26-11 @ 10:44 AM
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| supereal | -- 02-26-2011 @ 1:54 PM |
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In that case, I'd follow the wiring diagram and check each connection by placing voltmeter probes at each end of that leg and look for a bad or open connection. We have found open wires inside the insulation that are not apparent on the surface, particularly if they are the old type with rubber that is covered with fabric, or teminals that have become corroded where the wire joins. The whole six volts can be dropped (lost) with just a few ohms resistance. Another culprit is battery terminals where the acid has infiltrated between the cable and the clamp. Generator output requires the battery load. Don't depend on the dashboard ammeter to determine if the generator is working. Put the voltmeter across the battery terminals and watch while the engine is revved. If the voltage shows any increase, a high resistance in the system is probable.
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| 37RAGTOPMAN | -- 03-11-2011 @ 5:17 AM |
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lightflyer. you can try running a jumper wire, from the cutout directly to the battery..but first remove the original wiring, this will rule out the original wiring and gauges, use a volt meter on the battery, if the generator will work you will see a rise in voltage, did you try motoring the generator.?? lets hear how you made out, 37RAGTOPMAN
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| lightflyer1 | -- 03-11-2011 @ 12:25 PM |
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I will see if I can do this but I have a back surgery coming up to fuse two more vertebrae. One already done so it gives me some trouble when bending. I will see what if anything I can do.
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| tudorbilll | -- 04-10-2011 @ 10:06 AM |
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Super-What is the voltage at the battery if it is good and fully charged.Engine off.Also whats the votage drop to while cranking This message was edited by tudorbilll on 4-10-11 @ 10:35 AM
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| supereal | -- 04-10-2011 @ 10:43 AM |
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The usual pole-to-pole voltage of a "six volt" battery is about 6.5 volts, on average. A much better indication of battery power is a specific gravity test. It can be done with an inexpensive "eyedropper" tester that contains floating balls. Any test that shows the specific gravity below 1250 indicates a weak or dying battery, or both. This is after running the headlights a few minutes to remove the "surface charge". With the battery connected and engine running fast enough to close the cutout, look for about 7.5 volts at the battery. When trying to locate the source of electrical problems (and most others) it is important not to just start swapping parts or moving connections. Using a voltmeter, check between both the input and output of the cutout and the negative pole of the battery. The reading will show the loss in that part of the circuit, likely due to a defective battery cable and/or terminal. At six/seven volts, a relatively small resistance can "drop" the entire power. Do the same test between the positive (ground) pole of the battery and the frame of the generator. More often than not, charging problems, like many other auto electrical dilemmas, is the result of poor grounding from rust, paint, corrosion, and other obstacles. By swapping generators, cutouts, etc, you have probably eliminated those components. Do these recommended tests, and it is likely you will narrow down the cause. If you don't have a full wiring diagram for your '36, I can post one for you. It is a vital "road map" when diagnosing problems. To answer your other question, when running the starter, it is not unusual to see the battery voltage fall to around four volts. This message was edited by supereal on 4-10-11 @ 10:45 AM
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| TomO | -- 04-11-2011 @ 4:57 PM |
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My experience is a fully charged battery in good condition, will read 4.8 volts or more across the terminals when cranking the car with the starter. Any reading below 4.5 volts should be investigated. Either the battery is weak or the starter is drawing too much current. Tom
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| lightflyer1 | -- 04-17-2011 @ 7:13 PM |
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Double fusion complete and trying to heal now. Doing very well though. Might be a few more weeks before I can get back in there. Thanks for continueing to discuss!
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| ford38v8 | -- 04-17-2011 @ 8:18 PM |
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David, You're a braver man than most. I have a bad back myself, but can't imagine the constant pain that brought you to your decision. I wish you a speedy and successful recovery. Alan
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| lightflyer1 | -- 04-24-2011 @ 8:30 AM |
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Constant pain is a good motivator. I used a spine surgeon here rated in the top 100 in the world. Pain free since the surgery and still doing excellent after two weeks out! Used Dr. Dryer from Central Texas Spine Institute. Assisted my surgeon 25 years ago for the first one and now did 2 more fusions this time. Much different in a better way than the old days. I am extremely satisfied thus far. Will be checking the car in a few weeks. http://www.spine-ctsi.com/
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| MG | -- 04-24-2011 @ 3:37 PM |
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This has been a very informative thread. I've learned a lot about the charging system in these old Ford's and about what to expect from my bad back. Given the information posted here, I went out and made some voltage measurements on my '37. With the engine off the battery read 6.23 volts. I found that at idle the measurement at the battery posts read 7.5 volts. At high RPM it measured 8.2 volts. This would explain why my battery boiled several months ago? I will adjust the 3rd brush for 7.5 volts at fast idle. A question I have though, will the cutout points ever open with the 3rd brush set to the extreme mine is now set at? This message was edited by MG on 4-24-11 @ 3:50 PM
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| 37RAGTOPMAN | -- 04-24-2011 @ 4:00 PM |
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hook a volt meter and drive the car, if it still goes to 8 volts your generator fields might be on the way out, what is your amp meter reading on the road 30-35 mph,. ? this is also important. the generator only starts charging after 10 mph ,and should not go any higher no matter how fast you drive, it should stay at the set voltage and amps. It should charge the same at 10 mph as it does at 60 mph, it should read steady with a cutout, with the lights on it should just show a slight charge, and keep you eye on the battery so it stays charged.and not overcharged. being you boiled the battery once, I suspect the fields in the generator, I smoked a generator 2 summers ago,on the way home from a cruise night, it was 65 mile ride,and I smelled the fields burning, which also destroyed the ARM, I could not find a replacement right away, and I called CERTIFIED auto electric and orders a ALT,with all the adapters to install on my 37 85 HP,with original Ford fan, a one wire hook up and bolted on in 20 minutes, I can tell you one thing it does work excellant hope this helps this is my 3 cents 37RAGTOPMAN This message was edited by 37RAGTOPMAN on 4-24-11 @ 4:11 PM
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