641 6 volt coil question

[Tony Jacobs]

A 6 volt coil works just fine in a 12 volt conversion when you use an external resistor. Why do you think that most automotive and tractor manufacturers used external resistors when they first switched to 12 volt systems? Because they continued to use coils that were originally designed for 6 volts.

You are completely wrong . A 6 volt coil does not work in a 12 volt conversion and never will . When manufacturers switched to 12 volts they switched to 12 coils immediately . A resistor or internally resisted coil with 12 volts is used so that points do not get burned . You do not install a resistor to use a 6 volt coil in a 12 volt application because a resistor is used to cut the voltage to the points not to protect the coil . Soaked you are off your rocker if it works so well why did you have change out 6 volt coils to 12 volt coils ? Because of lack of spark during cranking and adding a resistor on it reduces spark during cranking even more .

 

[Tony Jacobs]

A 6 volt coil works just fine in a 12 volt conversion when you use an external resistor. Why do you think that most automotive and tractor manufacturers used external resistors when they first switched to 12 volt systems? Because they continued to use coils that were originally designed for 6 volts.

Since this is a Ford Board and we are talking about Ford Tractors I want to see your Ford Documentation of Ford using a 6 volt coil on a 12 volt application . Show me a parts catalog application with part numbers . A part number and a parts catalog that was printed by Ford during the changeover from 6 volt to 12 volt back was happening in 1956 . No aftermarket information no modern day current part numbers nothing but 1950’s original information as printed by Ford and only Ford no other manufacturers either .

 

[soaked]

From post #41
"Soaked you are off your rocker if it works so well why did you have change out 6 volt coils to 12 volt coils ? Because of lack of spark during cranking and adding a resistor on it reduces spark during cranking even more ."

There is no lack of spark if cranking the 6 volt coil by itself.
A 6 volt 1.2 ohm coil cranking with a 12.6 volt battery will start right up.

 

[Keith Williams]

You are completely wrong . A 6 volt coil does not work in a 12 volt conversion and never will . When manufacturers switched to 12 volts they switched to 12 coils immediately . A resistor or internally resisted coil with 12 volts is used so that points do not get burned . You do not install a resistor to use a 6 volt coil in a 12 volt application because a resistor is used to cut the voltage to the points not to protect the coil . Soaked you are off your rocker if it works so well why did you have change out 6 volt coils to 12 volt coils ? Because of lack of spark during cranking and adding a resistor on it reduces spark during cranking even more .

Sorry to disagree Tony,
6 Volt coil worked just fine with a BALLAST resistor added to the circuit to reduce the current flow thru the coil.
That's how my 64 Ford 4000 runs today.

V=I x R
Voltage = Current times Resistance (Voltage measured in Volts, Current measured in Amps, Resistance measured in Ohms)
Ohn's Law - simple electrical theory.
Double the resistance (coil plus a ballast resistor of equal resistance) when you double the voltage yields the same current flow.
Keith Williams

 

[Hacke]

Since this is a Ford Board and we are talking about Ford Tractors I want to see your Ford Documentation of Ford using a 6 volt coil on a 12 volt application . Show me a parts catalog application with part numbers . A part number and a parts catalog that was printed by Ford during the changeover from 6 volt to 12 volt back was happening in 1956 . No aftermarket information no modern day current part numbers nothing but 1950’s original information as printed by Ford and only Ford no other manufacturers either .

This is from a manual for Ford 1000-series, they all had 12 V systems. There was a mishap regarding the ballast resistor, see correction at red mark.

Anyhow, data for primary resistance and current through breaker points for the 5" coil make 6.3 - 6.8 V across the primary winding. A 6 V coil in a 12 V system from factory.

.

 

[Tony Jacobs]

This is from a manual for Ford 1000-series, they all had 12 V systems. There was a mishap regarding the ballast resistor, see correction at red mark.

Anyhow, data for primary resistance and current through breaker points for the 5" coil make 6.3 - 6.8 V across the primary winding. A 6 V coil in a 12 V system from factory.

View attachment 159148
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View attachment 159150

What the part number ? That doesn’t prove anything ? I forgot to ask how do you saturate a 6 volt coil with 6.3-6.8 volts ? That’s a 12 volt coil
With either an internal resistor or a resistance wire built into the harness which was typical on the three cylinder tractors . This particular debate has nothing to do with the three cylinder tractors because they all came from the factory as 12 volt tractors with 12 volt coils .

 

[Sean in PA]

Tony, please explain the difference between a 6 volt coil and a coil that says "12 volts external resistor required". The external resistor reduces the voltage at the points and primary to 6 volts, so the coil is essentially the same as a 6 volt coil except for the external markings.

 

[Tony Jacobs]

Sorry to disagree Tony,
6 Volt coil worked just fine with a BALLAST resistor added to the circuit to reduce the current flow thru the coil.
That's how my 64 Ford 4000 runs today.

V=I x R
Voltage = Current times Resistance (Voltage measured in Volts, Current measured in Amps, Resistance measured in Ohms)
Ohn's Law - simple electrical theory.
Double the resistance (coil plus a ballast resistor of equal resistance) when you double the voltage yields the same current flow.
Keith Williams

Sorry to disagree with you to but it doesn’t work . In theory it looks good on paper in the real world it doesnt work . Go take your tractor and put it on an Oscilloscope take a look at coil saturation spark length length of time in milliseconds to build spark between a 6 volt coil and a 12 volt coil and you will see why it doesn’t work . Then use both coils and start the tractor when it’s hot out . Then take both coils and start the tractor when it’s below zero out then you see how fast the 6 volt starts failing and why it doesn’t work and never will . It’s just hack job at best .

 

[Tony Jacobs]

Tony, please explain the difference between a 6 volt coil and a coil that says "12 volts external resistor required". The external resistor reduces the voltage at the points and primary to 6 volts, so the coil is essentially the same as a 6 volt coil except for the external markings.

I give you all the theory you want just as soon as you show me a Ford part number for a 6 volt coil
In a 12 volt application like you said everybody did in early manufacturing when they were converting from 6 volt to 12 volt . All I want is to see it in Ford Documentation , car , truck or tractor .

 

[Sean in PA]

I give you all the theory you want just as soon as you show me a Ford part number for a 6 volt coil
In a 12 volt application like you said everybody did in early manufacturing when they were converting from 6 volt to 12 volt . All I want is to see it in Ford Documentation , car , truck or tractor .

All of the 1965-1975 Ford tractors with gas engines had 12 volt systems and they all used an external resistance wire that is essentially the same as an external ballast resistor, so the voltage at the primary of those coils was 6 volts. The current part number on the NH parts site is D5TE12029AB. The description just says coil and does not specify 6 or 12 volt.

 

[Sean in PA]

If you do a Google search on "Does the D5TE12029AB coil require an external resistor in a 12 volt system?", the answer returned is "Yes, the D5TE12029AB ignition coil requires an external resistor when used in a 12-volt system".

 

[Tony Jacobs]

If you do a Google search on "Does the D5TE12029AB coil require an external resistor in a 12 volt system?", the answer returned is "Yes, the D5TE12029AB ignition coil requires an external resistor when used in a 12-volt system".

That particular coil is a 1975 3 cylinder tractor 12 volt factory installation coil which does use an external resistor because the original 3 cylinder application the tractor used a resistance wire in the wiring harness . It is NOT a 6 volt only coil like the 8BA 12029 coil that Soaked was talking about .

 

[Tony Jacobs]

All of the 1965-1975 Ford tractors with gas engines had 12 volt systems and they all used an external resistance wire that is essentially the same as an external ballast resistor, so the voltage at the primary of those coils was 6 volts. The current part number on the NH parts site is D5TE12029AB. The description just says coil and does not specify 6 or 12 volt.

It is a 12 volt only coil when it was produced by Ford it is not a 6 volt coil and never was from the factory . It is also not the current part . Show the theory behind 3.0 ohms creating 6 volts of resistance . I do not care about Aftermarket manufactured parts that use any random part number on any random chinese piece of crap coil . This debate started because ole Fred wanted to use a dedicated 6 volt only coil on his 12 volt hack conversion . You said it would work as did Soaked then you said all the manufacturers did that when they were converting from 6 volt to 12 volt . I told you a 6 volt ONLY coil will not work on a 12 volt application . So when you prove Ford put 6 volt coils on 12 volt applications I will explain the theory behind it . I do not care about any other manufacturer than Ford , I do not care about anything aftermarket this is about Ford and only Ford .

 

[Tony Jacobs]

Sorry to disagree Tony,
6 Volt coil worked just fine with a BALLAST resistor added to the circuit to reduce the current flow thru the coil.
That's how my 64 Ford 4000 runs today.

V=I x R
Voltage = Current times Resistance (Voltage measured in Volts, Current measured in Amps, Resistance measured in Ohms)
Ohn's Law - simple electrical theory.
Double the resistance (coil plus a ballast resistor of equal resistance) when you double the voltage yields the same current flow.
Keith Williams

I forgot to ask , you have a GENUINE Ford 6 volt ONLY coil that you prove it is 6 volt only that is the debate here . Not aftermarket coils , not later Ford coils .