The Ford Barn

Jim Boehmke · 04-07-2013, 12:36 PM

Tom, I found a nice '34 Ford in a garage last year and I now have it on the road.
The '34 has a wire wound ceramic resister and I've heard that this resistor is so that the distributor points don't "burn" up.
Why is this resistor needed on a '34 Ford and not on a Model A??
Thanks Tom.
Jim Boehmke

Tom Wesenberg · 04-07-2013, 12:48 PM

Quote:

Originally Posted by JimBoehmke

Tom, I found a nice '34 Ford in a garage last year and I now have it on the road.
The '34 has a wire wound ceramic resister and I've heard that this resistor is so that the distributor points don't "burn" up.
Why is this resistor needed on a '34 Ford and not on a Model A??
Thanks Tom.
Jim Boehmke

Jim, the resistor will drop the current through the points, and will also drop the voltage going through the coil primary. I'm not familure with the coil for the 34 Ford, but I'd check to see if that's what Ford originally used.

Jim Boehmke · 04-07-2013, 12:52 PM

Thanks Tom, Yes. all the early V-8's have these as stock equip.
JIm

Benson · 04-07-2013, 01:29 PM

Jim,

Here is some info I saved on my computer from the past:

MISC. IGNITION

VOLTAGE RESISTORS: These consist of a winding of a high resistance (nichrome) wire wound around a porcelain type insulator. This reduces the incoming 6 Volts to between 3 to 4-1/2 Volts (early Ford literature states it’s reduced to 4-1/2 Volts).

The thinking at the time was this decreased voltage would increase the life of the distributor points by reducing arcing. And with the difficulty in replacing the distributor points in these front mounted distributors, it was a very good idea. But it required a special 4-1/2 Volt coil.

Bypassing, or removing, this resistor from the circuit overloads the internally wound primary circuit in the coil and causes premature coil failure. However, it’s quite common to bypass these resistors when racing to increase the spark being delivered to the spark plugs. Because the car is moving (more air circulation around the coil) and combined with less idling, the coils were less prone to overheating and melting their tar insulation.

When the ’49 was introduced, Ford discontinued the voltage resistor for their newly designed ignition system and began using coils rated at 6 Volts.

I’m sorry I don’t have who submitted this to the FB site around Dec. 12, 2006.

Jim Boehmke · 04-07-2013, 01:44 PM

Great info. Benson. Thanks heaps.
JIm

tbirdtbird · 04-08-2013, 09:45 AM

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Correct, those coils were rated at 4 V

Special Coupe Frank · 04-08-2013, 10:39 AM

Ford N-model tractors with the distributor mounted on the front of the timing case used 'em too. By-pass that resistor, and the coil will open-up after about 1/2 hour of running.

04-07-2013, 12:36 PM	#1
Jim Boehmke Senior Member Join Date: May 2010 Posts: 344	Tom Wessinberg Question. POINTS Tom, I found a nice '34 Ford in a garage last year and I now have it on the road. The '34 has a wire wound ceramic resister and I've heard that this resistor is so that the distributor points don't "burn" up. Why is this resistor needed on a '34 Ford and not on a Model A?? Thanks Tom. Jim Boehmke

04-07-2013, 12:52 PM	#3
Jim Boehmke Senior Member Join Date: May 2010 Posts: 344	Re: Tom Wessinberg Question. POINTS Thanks Tom, Yes. all the early V-8's have these as stock equip. JIm

04-07-2013, 01:29 PM	#4
Benson Senior Member Join Date: May 2010 Posts: 2,597	Re: Tom Wessinberg Question. POINTS Jim, Here is some info I saved on my computer from the past: MISC. IGNITION VOLTAGE RESISTORS: These consist of a winding of a high resistance (nichrome) wire wound around a porcelain type insulator. This reduces the incoming 6 Volts to between 3 to 4-1/2 Volts (early Ford literature states it’s reduced to 4-1/2 Volts). The thinking at the time was this decreased voltage would increase the life of the distributor points by reducing arcing. And with the difficulty in replacing the distributor points in these front mounted distributors, it was a very good idea. But it required a special 4-1/2 Volt coil. Bypassing, or removing, this resistor from the circuit overloads the internally wound primary circuit in the coil and causes premature coil failure. However, it’s quite common to bypass these resistors when racing to increase the spark being delivered to the spark plugs. Because the car is moving (more air circulation around the coil) and combined with less idling, the coils were less prone to overheating and melting their tar insulation. When the ’49 was introduced, Ford discontinued the voltage resistor for their newly designed ignition system and began using coils rated at 6 Volts. I’m sorry I don’t have who submitted this to the FB site around Dec. 12, 2006.

04-07-2013, 01:44 PM	#5
Jim Boehmke Senior Member Join Date: May 2010 Posts: 344	Re: Tom Wessinberg Question. POINTS Great info. Benson. Thanks heaps. JIm

04-08-2013, 09:45 AM	#6
tbirdtbird BANNED Join Date: May 2012 Location: inside your RAM Posts: 3,134	Re: Tom Wessinberg Question. POINTS Sponsored Links (Register now to hide all advertisements) Correct, those coils were rated at 4 V __________________ '31 180A

04-08-2013, 10:39 AM	#7
Special Coupe Frank Senior Member Join Date: May 2010 Location: Northeast Penna Posts: 2,108	Re: Tom Wessinberg Question. POINTS Ford N-model tractors with the distributor mounted on the front of the timing case used 'em too. By-pass that resistor, and the coil will open-up after about 1/2 hour of running.