Topic: 40 Ford Electrical problem.


bwhitworth    -- 12-29-2011 @ 1:55 PM
  I am having intermittant electrical problems with no current to the coil. I can hot wire it from the coil to the battery and it starts right up. To turn the engine off I have to remove the wire. I think there is a break in the red wire between the ignition switch and the coil. The resistor is getting hot, so the current is getting that far. If I installed a new wire from the ignition an the coil, bypassing the resistor, what would happen?


ford38v8    -- 12-29-2011 @ 2:30 PM
  Your resistor is needed in the circuit to reduce the voltage to the coil. Without it, your coil will suffer an early death. You say you have intermittent problems, which may be understood as having a weak coil to begin with, or as having too much resistance in your circuit. Your coil is happiest with 3 to 4 volts, so if you can determine what it is actually getting, you're on the right track to a better runningn Ford.

Alan

This message was edited by ford38v8 on 12-29-11 @ 2:31 PM


supereal    -- 12-29-2011 @ 3:07 PM
  More often than not, that problem is due to a worn ignition switch. The moveable part wears a groove in the body of the switch. We replace them as a matter of usual restoration.


37RAGTOPMAN    -- 12-29-2011 @ 5:03 PM
  you could check the inside of the switch,for worn grooves on the brass contacts and bakelite housing,
disconnect the battery,
take the wires off the switch,
remove the back cover,the bakelite piece with the brass contacts,
you can use a piece of flat glass and some 320 wet and dry sand paper and draw the bakelite switch across the sand paper. this will remove the grooves that are in the black bakelite housing,and clean up the brass contacts so they are like new,
and you can also clean the contact brush by polishing it or try finding a replacement,
hope this helps, 37RAGTOPMAN
you did not say how old the wiring is,make sure it is not brittle or fraying,this will cause probems,
if the resister is getting hot,the coil should be receiving currant,make sure you check it out,

This message was edited by 37RAGTOPMAN on 1-12-12 @ 4:14 PM


TomO    -- 12-31-2011 @ 7:53 AM
  Check for a break in the wire near the terminal for the coil, by pulling on the terminal when it is disconnected from the coil. Do not use pliers to pull as you can break the wire.

If the wire is not broken there, try running a jumper wire from the resistor to the coil terminal. If you still have the problem, use your jumper wire to bypass the ignition switch, by connecting your jumper from the battery post of the switch to the input of the resistor.

It is always better to try to isolate the area of failure before disassembling any part of an electrical circuit. taking something apart and putting it back together can cause new problems or temporarily fix a problem.

Tom


c-gor    -- 01-01-2012 @ 5:42 AM
  Supereal is most likely correct. I was experiencing the same problem. After removing the ignition switch on my 1940,found that the brass section was significantly worn. The slider has teats that complete the ignition circuit. The brass onto which they contact becomes dirty and worn resulting in high resistance. Suggest you remove the switch examine it and if a cleaning will work fine. If not Carpenter sells a repro switch that is acceptable.


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