8N doesn't start

[Soundguy]

no apology needed. ( and I meant no offense personally..)

I'm perhaps guilty of being too 'matter of fact'.

lets call it water under the bridge no harm no foul and both go along and have a great day.

soundguy

 

[GPintheMitten]

Well, did you ever get it started? How's it going on this?

 

[CraigM]

I was going to start a new thread on this project, but since GP asked how it was going, I'll just continue here.

Got the plug threads chased and plugs installed. No problems there. Tightened the nut on the broken binding post on the resistor and figured we'd give it a spin to see if it would even cough on the gas left in the carb before we thought of putting the hood back on. It's completely dead. No spark any way we tested it. Remembering how the spark has randomly been anywhere from very strong to non-existent, we began to follow wires. Noticed that the resistor had been jumped, and the jumper wire had pulled out of the crimp terminal that held it. Hmmm.

The tractor has a few switches and other electrical components that don't show up on any diagrams. Some of it looks like it might belong to a jubilee edition of the tractor. The owner says that none of the switches work. We see a few wires just hanging in the breeze anyhow and are just about ready to rip out anything that doesn't look like it belongs on the assumption that anything extra is just another problem waiting to happen. There is a small part of me that wants to try to preserve anything that might be original/authentic if it's not too much of an ordeal.

I hope the attached pix show things well enough for talking purposes. No. 1 shows the right side of the dashboard. You can see a red fuse holder mounted under the dash, and several items hanging on wires. The fuse holder has a 20A glass cartridge fuse in it. The hanging things were monted in holes drilled in the extreme right edge of the hood. The hanging things are a switch and a device I can't identify. The mystery item reminds me of the resettable fuses in the panel of Cessnas that I used to fly, but there is no number to indicate amperage. There was also an indicator light that isn't in the pic mounted with the switch and unknown. No. 2 shows the panel. I believe that the push-pull switch to the right of the keychain ornament is the original light switch. At the same height, but on the opposite side of the panel is a military style toggle switch. In order to operate this switch, you have to pull the handle out first to unlock it. I don't know what it's connected to, haven't had time to study it and try to make sense of it all.

Can anyone sort this out? What am I looking at?

 

[J_J]

That square thing in the middle is an aircraft type circuit breaker. The amperage is printed or stamped on the round button.

 

[GPintheMitten]

Apart from the ignition system, there isn't anything electrical excepts lights.

My guess is someone added some extra lights, maybe a CB or other radio and made up some switches and fuses/breakers for them.

I don't think that wiring would be causing an intermittent spark. But I suppose someone may have wired in a switch to prevent spark as a theft prevention.

 

[Soundguy]

If in doubt, dyke it out.

start over. you can make that tractor run with about 4' of wire and a couple terminal ends.

soundguy

 

[CraigM]

J_J, I thought it looked like an aircraft breaker. The amperage must be printed and then painted over 'cause there isn't even a hint of any stamping under the paint.

GP, I think the intermittent spark is probably the loose/broken connections at the resistor. Any accessories added by previous owners should have been off to the side, so to speak, of the ignition system, but there are enough extras and hanging wire ends under there that anything is possible.

Soundguy, from looking at the wire diagrams that another poster linked me to, you have got to be about right about 4' and a couple of terminals. The work I see was probably done by several people in the past 'cause some of it is really first rate, and some is pretty hammed up. I just didn't want to go and tear out something only to find out later it was something that should have been left. I'm gonna go get a new resistor and start over with the wiring.

Thanks everyone.

 

[J_J]

Someone correct me if I am wrong, but did they not have two wires going to the terminal on the coil. One wire came straight off the start wire to the coil, bypassing the resister to give more voltage to the coil for max spark, and after starting, in the run mode, the 12v goes through the resister to regulate the current. That is about all you need as far as voltage to get a spark, assuming the points and cap is good and timing set. The plug gap should be set first, and then the timing. I used to use an battery AM radio to set timing with no timing light available. You hear a pop when the points open. You don't have to turn the engine to test spark either. As long as you have 12 v to coil, a screw driver to open the points will cause a spark. It really is a simple circuit.

This diagram might help some as far as the wiring. Look at the two wires going to the coil.

http://www.familycar.com/CLASSROOM/ignition.htm

http://home.earthlink.net/~8ntractor/12volt.html

Yea, I know, I looked at the diagram and it only has one wire to coil.

Some coils had built in resistors.

 

[GPintheMitten]

Craig,

Do you know whether it is 12volt or 6volt? I don't recall you saying one way or the other.

I agree, simplify the wiring to just get the darn thing firing and running. The owner can always wire in lights with a switch. That part is simple.

I wouldn't worry too much about keeping it 'original' as it relates to the wiring. I think that ship sailed long ago.

 

[Soundguy]

No..

if it's a front mount coil, power goes thru the oem ballast resistor.. the oem ballast resistor has a thermal coeficient. when it is cold.. it has low ressitance .. thus more power to the coil.. after about a minute it has heated up to max and stabilized so that on a 6v system, the voltage at the top of the coil is between 3.5 and 2.8v or so.

ont he round can side mount coils.. they ran on straight 6v.

if you convert either setup to 12v, you need to add in a seperate series resistor, or for the side mount, get a true 12v coil that has the correct primary resistance.

those fords did not use the ignition bypass solenoid setups that some machines did.

later fords incorporated a ressitor wire to the coil.. etc.

soundguy

Someone correct me if I am wrong, but did they not have two wires going to the terminal on the coil. One wire came straight off the start wire to the coil, bypassing the resister to give more voltage to the coil for max spark, and after starting, in the run mode, the 12v goes through the resister to regulate the current. That is about all you need as far as voltage to get a spark, assuming the points and cap is good and timing set. The plug gap should be set first, and then the timing. I used to use an battery AM radio to set timing with no timing light available. You hear a pop when the points open. You don't have to turn the engine to test spark either. As long as you have 12 v to coil, a screw driver to open the points will cause a spark. It really is a simple circuit.

This diagram might help some as far as the wiring. Look at the two wires going to the coil.

Ignition Systems  A Short Course

Ford 8N Tractor 12 Volt Conversion

Yea, I know, I looked at the diagram and it only has one wire to coil.

Some coils had built in resistors.