Topic: It was Smoking


Dream38v8    -- 08-25-2026 @ 1:11 PM
  I know I connected something incorrectly. My question is what did I do wrong?
I got the car running a few weeks ago. I noticed the gauges would work intermittently. On my last drive I noticed the amp gauge was not charging, but if I turned on the lights it would discharge. I ran a test. I disconnected the positive battery cable and the engine stopped. Hence a bad generator. I replaced the generator brushes and reconnected the cut-off and battery. As I was attempting to start the car the amp gauge was negatively pegged. I turned the car off and the gauge returned to 0. I tried to start the car again. This time smoke came from under the dash and hood. I tuned the car off and disconnected the battery. The cut-off was smoking and the plus the ignition wire to the solenoid. Smoke under the dash appeared to be coming from the back of the gauges. After the smoke cleared I crawled under the dash. The wire from the wiring harness to the amp gauge was disconnected. I looked as if the connector had burned or melted off. Also the yellow plastic wire covering was melting through the wiring harness. I know the car will require a new cutoff, solenoid and under dash wiring harness. What else? As I stated earlier what did I do incorrectly? The first pic is from under the dash and the second is at the solenoid,

Ray


Dream38v8    -- 08-26-2026 @ 12:28 PM
  Today I had time to do a little investigating. I took the generator apart and it looks fine. No loose wires and none touching the outside case. The one new think I found was the cutout connection. It looked as if it was extremely hot. The outside are around the connection has smoke damage.

Any ideas.

Ray


flatfoot    -- 08-27-2026 @ 9:37 AM
  What year is the car you are working on?


Dream38v8    -- 08-27-2026 @ 10:12 AM
  Flatfoot, my car is a 1938 Fordor Deluxe.

Ray


Dream38v8    -- 09-07-2026 @ 1:50 PM
  I'm thinking the issue was caused by the cut-off shorting out. Therefore I am considering replacing the generator and associated electrical gear with a 6 volt alternator and electric fan. I am seriously considering making this switch since '38 is not a show car. Any comments on what else to consider regarding my proposed switch.

Thank you,

Ray


carcrazy    -- 09-07-2026 @ 4:56 PM
  You might want to consider going with a 12V negative ground electrical system using an alternator.

The disadvantages associated with going to 12V are you will have to change some of the 6V items in the car like the battery, starter motor, coil, all light bulbs and any blower motors or overdrive solenoids.

The advantages of going to 12V are you can use a common alternator from a GM car as either a new or rebuilt unit that will have 63 amp current output. The alternator you want to use is most likely the GM Model 10 SI which has a built in voltage regulator. This was standard on all GM cars and trucks built from 1973 through 1985. You will want to use a DA Plug (it is a Diode) which prevents the alternator current from flowing backward through the ignition circuit after you shut the engine off. If you buy a rebuilt alternator from one of the auto parts stores like AutoZone, you will have to pay an additional core charge of $10 to $15 because you won't have a core to trade in. Once you have the car converted to 12V, you will be able to use modern 12V accessories to make the car a reliable everyday driver. These accessories include radios, cruise control and if you want it, air conditioning.

Many more items need to be addressed when doing a 6V to 12V conversion. A good source of information about this swap is "The Official 12-Volt Conversion Guide" by Randy Rundle of Fifth Avenue Antique Auto Parts.

This message was edited by carcrazy on 9-7-26 @ 5:07 PM


Dream38v8    -- 09-08-2026 @ 5:31 AM
  Thanks Carcrazy for the info regarding switching to a 12V negative ground system. I plan to stay with the 6V positive ground system. The next owner may want to keep the car original. Currently the only non stock items are the Fender headers and fog lights. Hence the car is very original. What I am looking for is info needed to accomplish the change to an alternator. . What else is required besides the fan and alternator? What vendor has the best equipment and support?

Ray


51504bat    -- 09-08-2026 @ 6:18 AM
  First off, I'm a 12 volt guy but understand if you want to remain true with 6 volt positive ground. I've used these guys for 3 alternators, 2 for flatheads and one for the 302 in my '54 Ranch Wagon. Worth checking them out. IMO
https://www.qualitypowerauto.com/item_24/6-Volt-Alternators-Positive-Ground.htm

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Kens 36    -- 09-08-2026 @ 7:39 AM
  Are there issues to consider with the fan mounting on the alternator?


carcrazy    -- 09-08-2026 @ 4:41 PM
  You can buy a 6V alternator from Fifth Avenue. It will be a 6V negative ground unit but that shouldn't present any problems unless you have a modern electronic vibrator in you radio. The original mechanical radio vibrators will work fine with either positive or negative ground.

Fifth Avenue also offers a 6V electrical cooling fan with metal mounting straps to allow you to mount the fan motor to the sh*ll of the radiator rather than to the radiator core. They also offer everything else you need to install an alternator on your engine. Other vendors also offer the pulley and mounting bracket for the alternator. Some of the other vendors may have less expensive parts.

https://fifthaveinternetgarage.com/index.php


Dream38v8    -- 09-09-2026 @ 12:35 PM
  51 and Carcrazy, I am seriously considering switching to the 6V alternator electrical system. The system I will probably purchase is from Fifth Avenue Internet Garage. They have a pulley that allows attaching the original fan to the alternator. Hence no electrical fan connected to the radiator.

Other house projects are in the way of working on the '38 at this time. It will probably be a few months before I get started. I will post an update as I start and complete the alternator switch.

Thank you!

Ray


RAK402A    -- 09-09-2026 @ 5:57 PM
  I put a 6 volt alternator from E. J. Whitney in my 1940 Ford about five years ago.

He re-uses original Ford generator parts, so it looks correct. It does not have the incorrect GM style fan pulley. The pulley is cast like the original, but slightly smaller than the stock one to keep the RPM on the alternator up.

As the support is original cast iron, it does not fail like some of the aluminum ones reportedly do.

https://ejwhitneyco.com/automotive.html


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