ford 8n will not fire

[J_J]

Did you check to see if the breaker plate was grounded?

Did you install a good capacitor?

With the points open, the path from the terminal on the coil to ground should be open. With the points closed, you should have some resistance.

The points is what makes the ground for the coil to charge up, and when the points open, the high voltage collapses and the plug should fire.

With the coil out of the system and laying on a table, and the HV wire laying close to ground, you should be able to apply voltage to the coil, by grounding the point terminal, and when you remove the ground, there should be spark. If not, you have a coil problem.

Some coils also have a built in resister. The resister is there to limit current.

If the coil has an external resister, some circuits will bypassed the external resister for a hotter spark, by applying more voltage. Otherwise, the start terminal will apply 6 volts to the coil and when the engine is running, the coil gets it 's voltage from the run circuit/terminal.

Is this 8n a 12v modified system. and are you matching up the coil with the correct voltage?

The coil should indicate on the case if it has an internal resister.

If you look at the diagram above for the ign system, you should see everything I have said is true.

The 6 volt coils usually measure from 0.5 to 1 ohm. The 12 volt coils measure anywhere from 1 to 3.5 ohms.

http://www.myfordtractors.com/theorycalc.shtml

 

[whodat526]

put in new breaker plate and it did not help.I unhooked the resistor for a few minutes and got fire. i have three resistors that are the same. Can you tell me what value resistor i need. I know i need the resistor inline or it will smoke the coil but is everyone for sure they are not makeing the coil with one inside of it now. I bought the coil from TSC.

i dont believe they make a front mount coil with a internal resistor

 

[J_J]

Just about any 6 v coil will work in a 6 v system, as long as you have some kind of current limiting device. If it was built with internal resister, that is fine. You add what is required to operate the circuit. Same for 12v, you can play with the current using different resister values for more spark, but should limit the HV to about 30,000 to 40,000 v .

 

[whodat526]

Just about any 6 v coil will work in a 6 v system, as long as you have some kind of current limiting device. If it was built with internal resister, that is fine. You add what is required to operate the circuit. Same for 12v, you can play with the current using different resister values for more spark, but should limit the HV to about 30,000 to 40,000 v .

the front mount coils is made totaly different than any coil out there it is square and mounts right on the distributor

 

[J_J]

To bypass the square can coil,

Excerpt:

Remove the guts from the original square-can coil and bring the leads out to connect to a more reliable round-can coil. You still need to match the correct coil and ignition resistor to get about 4 ohms of resistance total. But the round can coil will take a lot more abuse, so you have a wider margin of error to play with.

 

[Army grunt]

2 things come to mind, I had a 601 work master,Got a great deal on it because it had a short that caused it to skip, an not start sometimes.I found after a lot of looking the wire that fed the points, on the underside where it passed through the side of the dis.what would happen was when you would take the cap off the wire would move just enough so you would see fire. Also i replaced the key switch an all wiring it was easy to do an only took a day. I used a 6 volt system an had no problem as long as it was charged fully.
If the tractor has set out in the weather the wires get caroded, an just don't carry electricity well.
Army grunt

 

[Soundguy]

put in new breaker plate and it did not help.I unhooked the resistor for a few minutes and got fire. i have three resistors that are the same. Can you tell me what value resistor i need. I know i need the resistor inline or it will smoke the coil but is everyone for sure they are not makeing the coil with one inside of it now. I bought the coil from TSC.

there are NO coils with a resistive element inside the can.

coils are made with a specific wire diameter and # of turns on the primary and secondary for their specific resistange and high voltage output.

front mount square N coils, best I have seen are 2.5 ohms if you get one marked 12v..

primary current should be 3-4a.. play with the ressitors you have to get that. in most cases the oem dash ballast resistor and a 2.5 ohm coil are fine.

soundguy

 

[Soundguy]

2 things come to mind, I had a 601 work master,Got a great deal on it because it had a short that caused it to skip, an not start sometimes.I found after a lot of looking the wire that fed the points, on the underside where it passed through the side of the dis.what would happen was when you would take the cap off the wire would move just enough so you would see fire. Also i replaced the key switch an all wiring it was easy to do an only took a day. I used a 6 volt system an had no problem as long as it was charged fully.
If the tractor has set out in the weather the wires get caroded, an just don't carry electricity well.
Army grunt

side and front mount distribuitors are 110% different in how they are setup to work with the coil.

you CAN use a round coil on a front mount if you gut an old square coil, or buy / build a blank off plate with correct connections.

if you do that.. get rid of all resistors and use a coil made to run 12v natively.. like a napa ic14sb.

no rocket science here.. the antique tractor boards I frequent this is electronics 101 stuff.. stuff the gys learn the 1st day they buy their old frontmount ford. it's one of the most troubling areas for some people.. that front mount dizzy. just have to play by it's rules.. or change the rules a bit

 

[J_J]

there are NO coils with a resistive element inside the can.

coils are made with a specific wire diameter and # of turns on the primary and secondary for their specific resistange and high voltage output.

front mount square N coils, best I have seen are 2.5 ohms if you get one marked 12v..

primary current should be 3-4a.. play with the ressitors you have to get that. in most cases the oem dash ballast resistor and a 2.5 ohm coil are fine.

soundguy

There are many coils that have internal resistive elements.

Here is one that has the internal resister.

IGNITION COILS AND RESISTORS

 

[J_J]

catfishonly,

Have you got the 8N fixed ?

 

[Soundguy]

There are many coils that have internal resisters.

Here is one that has the internal resister.

IGNITION COILS AND RESISTORS

so what 'ford' front mount does that mallory coil fit? we are, after all taking about ford front mounts.

PS.. I bet if you cut that coil in half.. it won't have a resistor in it.. but rather be wound correctly for intended primary voltage. 'internal / external' resistor is carry-over terminology from days gone by.. resistive elemnts disipate power and make extra waste heat.. Napa coils used to use this terminology.. a call to their tech department and finally a schematic of various coils found that none of their 'internal resistor' coils actually had resistors.. but were rather wound with correct primary wire. the IC14 was such a coil.

I don't have the schematic for that mallory.. but I'd be inclined to believe it is made in the same industry standard way.. just too easy to add a few extra windings of correct wire of the right diamter, than to load and pot it with a carbon composite chunk.

again.. moot point.. it's not a ford frontmount coil like we were talking baout in this thread.

ifn ya got a link to a ford front mount N coil that says it has a resistor, then we can talk

soundguy

 

[J_J]

With all due respects, if you are going to stick with factory stock parts, you are probably right.

I have an 8N, and my parts don't have to be stock to work great.

The fact is that if you are only looking for a good hot spark, any coil will work. You only need something to trigger the HV. You can even do the electronic ignition with no points, for 6 or 12 v, and eliminate most if not all the troubles from the past.

 

[RickB]

With all due respects, if you are going to stick with factory stock parts, you are probably right.

I have an 8N, and my parts don't have to be stock to work great.

The fact is that if you are only looking for a good hot spark, any coil will work. You only need something to trigger the HV. You can even do the electronic ignition with no points, for 6 or 12 v, and eliminate most if not all the troubles from the past.

Advocating a 6V EI conversion as a way to eliminate problems speaks volumes about your level of experience on this topic. I all but refuse to sell them, and do my best to convince folks that if they want EI a 12V conversion is part of the process.
I'll also take a wild guess and say that your 8N is a 1950 or later with the conventional side mount ignition considering your enthusiastic comments about the generic nature of ignition coils.

 

[J_J]

Just what problems are you seeing with the 6 v electronic conversions. All it is doing is replacing the points. 12v conversions do the same thing, using a 12v coil.

Electronic Ignition Conversion Kit - EF4FMP6

MY 8N has the front side mount distributor, but that should have no bearing about what can or will work. Is there any reason you can't rework the other distributor and make it work with a round coil?

 

[catfishonly]

catfishonly,

Have you got the 8N fixed ?

no not yet just got in from work and going out to mess with it some more.But one more thing is there a diffirence in the points 6volt verses 12 volt points.

 

[RickB]

Just what problems are you seeing with the 6 v electronic conversions. All it is doing is replacing the points. 12v conversions do the same thing, using a 12v coil.

Electronic Ignition Conversion Kit - EF4FMP6

Current draw on a decrepit old 6V starter will cause sufficient voltage drop to prevent the 6V EI unit from firing the ignition. The customer starts out with an ignition that won't fire consistently due to voltage drop while cranking , converts to EI and ends up with an ignition that won't fire at all. The range of voltage that a 6V EI will operate successfully within is quite narrow.

MY 8N has the front side mount distributor, but that should have no bearing about what can or will work. Is there any reason you can't rework the other distributor and make it work with a round coil?

Sure you can. like a guy I used to work with always said, "if it ain't a cob, it ain't a job". It will look like crap, take more time and cost more than installing the correct parts and being done with it. There's a guy on TBN who put EI with unit coils AND fuel injection on an old Case tractor because he wanted the challenge of figuring it out and making it work. Doesn't mean anyone in their right mind would do it with the stated purpose of making the tractor run better.

 

[J_J]

I would just tell the parts guy the year and what distributor you have.

When you get the points installed, and set the gap, then check the points, put a ohm meter or light tester on it and check for open and then put a screw driver between the points and you should read 0, or the test light should come on. If you do the buzzer thing, it should buzz when points closed, and quit when they open

 

[Soundguy]

JJ.. i think you may be missing some of the BIG differences between the side mount dizzy that uses a regulr 'coke can' looking coil, and no ballast resistor, on 6v, and the front mount ford coil that is square, and sets atop the distribuitor, and DOES use a ballast resistor, for 6v.

Those EI generally have a working volt range at right about 5v, with hairy operation down to 4.5v

add starter drawdown and you are right on the bleeping edge of that ei module logic having enough juice to fire or not.

that's why 12v and ei on them ford front mounts are always suggested.

the way the coil is built, it has a spring flat tab and pig tail coil on the bottom.. the flat tab touches a contact on the dizzy cap for KV to xfer thru.. the pigtail sets in a concave screwhead for the points.

there are delete kits.. but not cheap.. and you can farmerize a setup by gutting a coil and hogging the innards out and using a round coil to make the juju happen.. but again.. if I went EI.. i'd go 12v on that unit.

ps.. it's not an issue of aftermarket vs dealer supplied parts. that ford front mount coil is a darn specialty item.. I'd wager there is one chinese co cranking them out and that's who the major distribuitors get them from.. i know our local dealer is selling tisco ifgnition parts.. same as TSC.. etc.

soundguy

 

[J_J]

My system is modified to 12v, but kept the 6v starter. I will replace it if it ever goes bad. I also agree on the low voltage when starting, but according to the circuit description, I believe they will operate as low as 4.5 v.

While in the Navy as early as 1961, I was an Aviation Electronics technician, and building Capacitive Discharge ign system, and modifying ignition system. We were using SCR's as the trigger circuit, and hall effect circuits and photo cell circuits. I may still have a few units around, but they be old now, but will probably still work.

RickB,

I was probably building electronic circuit before you were even born. What do I have to do to become qualified? And no, I am not working at a Ford/New Holland dealerhhip.

If you want to put me on your ignore list, go for it.

 

[catfishonly]

i worked on the tractor again last night.I cut the side out of a old cap i wanted to see if i was getting spark at the rotobutton and i was the problem is i am not getting the spark at the contact inside the cap for 1243 it is fireing inbetween the brass contacts like it is out of time. i tried to advance it it see if it would make a difference but it did not then i went the other way still no change it is fireing but not where it is supposed to.How could this have gotten out of time by just sitting. Also is it best if i go ahead and buy the EI to do away with the points would this be cheaper in the long run or will it cost more how long do they last.