Topic: 1939 Ford Wiring Daigram


Frosty    -- 11-18-2017 @ 1:19 PM
 
Does anyone have a link to a 1939 Ford 4-door wiring diagram?


MG    -- 11-18-2017 @ 3:00 PM
  Click on this link and select the year you want > http://www.vanpeltsales.com/FH_web/flathead_drawings_electrical.htm



Frosty    -- 11-19-2017 @ 8:34 PM
  Thanks, I've got that sheet, I was looking for a bit more detail for the starting system.

Cheers, Al


TomO    -- 11-20-2017 @ 8:56 AM
  What kind of detail are you looking for?

The battery cable and the main feed for the rest of the car go on the drivers side post on the solenoid, the center contact goes to the starter button, where it supplies ground to pick the solenoid and the passenger side terminal of the solenoid goes to the starter.

Tom


Frosty    -- 11-27-2017 @ 3:36 PM
  First off, this car belongs to a good friend. The car has been in storage for 5 or 6 years. Not sure if it was running previously or not. He acquired it sight unseen.
The motor turns over but will not start. There is no spark at the plugs. The wiring is in poor shape with some insulation missing in places. I wanted a diagram of the ignition system with color coding so I could trace the wiring which has had some wires replaced over the years. tomorrow. I'll take a volt meter over to see what reading I can get at various locations.


TomO    -- 11-27-2017 @ 7:22 PM
  This diagram has the color coded wiring

http://www.vanpeltsales.com/FH_web/FH_images/FH_electrical-pics/Flathead_Electrical_wiring1939std.jpg

You should have battery voltage at the ignition resister terminal with the red with black tracer wire. This is about the middle of the circuit. The voltage at the coil will be around 2-4 v.

The points may have corrosion on them after sitting so long.

Tom


Frosty    -- 11-28-2017 @ 12:28 PM
 
Thanks Tom.


Frosty    -- 12-02-2017 @ 2:09 PM
 
After checking out the wiring, I found the ignition switch was the culprit. I bypassed the switch and managed to get the engine started.

Thanks for the comments & suggestions.

Frosty



mrtexas    -- 12-02-2017 @ 2:30 PM
  There is not a lot of detail for 39 cars. Wiring is very simple.


TomO    -- 12-03-2017 @ 2:38 PM
  You can remove the ignition switch and clean it, then re-install it.

I like to use a pencil eraser to clean off light corrosion and add a little tension to he switch brush. Put a thin coat of Vaseline on the switch plate to slow down the corrosion.

Tom


ford38v8    -- 12-03-2017 @ 10:27 PM
  Frosty, If you have hot-wired it past the ignition switch, you likely will have also bypassed the ignition resistor, located on the dash above the steering column. Bypassing the resistor is ok for a short duration, but will fry the coil and points if permitted to run with the full 6v battery voltage directly to the coil.

If you check voltage at the coil, you'll get full voltage unless the points are closed, at which time you'll read the resistor, which drops voltage by about 2v. The engine is happiest with 3 1/2 - 4 v.

Alan


JayChicago    -- 12-04-2017 @ 11:35 AM
  TomO
OK to use Vaseline? I use light bulb grease in such applications, because I feel safe it is formulated to protect the metal surface while still conducting electricity well. But I would have been afraid to use some other grease, afraid it would be a dielectric, adding resistance to the circuit. Maybe I'm just over-thinking again. Is it just that any resistance from such a thin film of grease is negligible?


JayChicago    -- 12-04-2017 @ 12:58 PM
  I believe the 3-1/2 to 4 volts at the coil is only when everything else in the electrical system is optimum, like with a good fully charged battery reading 6.5 volts, or when engine is running. As I learned the hard way, if your battery is a little discharged, like what happens when you've been in the garage trouble-shooting a while, battery now reading 6.0 volts, I think the reading at the coil will be closer to 2.5 volts.

I measured voltage drop across several different resistors and found all were very close to a full 3 volts.(with engine stopped) And you can expect another few tenths of a volt drop thru the ignition switch and rest of the circuit. So, with engine stopped, the total voltage drop ahead of the coil is 3 to 3.5 volts.


TomO    -- 12-05-2017 @ 7:19 AM
  Jay, I was taught to use Vaseline on switches back in the early 1950s and have had no problems because I used it. I last cleaned my ignition switch in 1977 and my dimmer switch in 2005. I used Vaseline in both of them. Bulb grease is a fairly new product, that became available in the 1990s to use on the new style bulbs. It would probably work just as good and maybe a little better.



Tom


Frosty    -- 12-11-2017 @ 8:14 PM
 
I hooked up the battery to the ignition side of the ballast resistor which is installed on the engine side of the firewall and get a reading of 2.5 to 3 v going out the other side to the coil. I've only done this to get the engine started for a few minutes to check out the engine. I'll be checking out the ignition switch next to see what the problem is.
I restored a 1938 Fordor a few years ago and don't recall that there was a ballast resistor on the engine side of the firewall. Is this perhaps something that the previous owner installed for some reason or is it a normal part of the wiring for a 1939? The car does have the fuse block and resistor under the dash.




JayChicago    -- 12-13-2017 @ 5:31 PM
  I think you called that right: that's something added by a previous owner. Probably because they couldn't find the source of the problem in the original ignition circuit, so they added a second feed to the coil. At least they were aware enough to include a ballast resister.


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