Another 8N ignirion question

[deerefan]

I replaced the coil on my 52 8 N with napa IC14sb as suggested in another thread. I replaced the wiring on the tractor also since the old wires were in bad shape. It is wired as follows- I have one wire going from the alt to the pos batt cable. I have on wire going from the starter button to the starter solenoid (small post closest to block). I have one wire plus the pos battery cable hooked to the solenoid post closest to the batt tray. I have one wire to the pos side of the coil hooked to the wire on the solenoid post closest to the batt tray. The neg coil post is hooked the dist as before. I am getting no spark from the coil. Thoughts? Hope i was clear enough!!

 

[Soundguy]

so far sounds like the coil is permanently HOTWIRED as it is getting power from the battery full time./ I see no mention of a switch between the coil and battery.

I can also tell you don't have an ammeter either.. something that would have helped diagnose your issue.

sounds like a cruddy 1 wire alternator setup too....

if points were closed.. by now coil has liekly died and points burnt.

post back further details.

 

[deerefan]

so far sounds like the coil is permanently HOTWIRED as it is getting power from the battery full time./ I see no mention of a switch between the coil and battery.

I can also tell you don't have an ammeter either.. something that would have helped diagnose your issue.

sounds like a cruddy 1 wire alternator setup too....

if points were closed.. by now coil has liekly died and points burnt.

post back further details.

Sorry. There is a switch.

 

[Soundguy]

ok.. no sparks... check power at incoming wire to coil primary. check power on wire to dizzy. if primary is continous and you have power on input.. should have power on output. if you do.. points are open. check gap.

.025.

check that points are not closed up.. or the feed thru insulator is not shorted.

rarely, you can have a condensor short out.

sparks happen when points open, anfter having been closed and coil charging..

 

[deerefan]

ok.. no sparks... check power at incoming wire to coil primary. check power on wire to dizzy. if primary is continous and you have power on input.. should have power on output. if you do.. points are open. check gap.

.025.

check that points are not closed up.. or the feed thru insulator is not shorted.

rarely, you can have a condensor short out.

sparks happen when points open, anfter having been closed and coil charging..

I am usually a pretty decent mechanic. This simple tractor gives me fits sometimes. I replaced the head gasket a few months back and after using it left the switch on and burnt some wires and coil. The new coil was getting juice. It was warm and i metered 12v at the positive lug. I tried grounding the coil wire to the frame and exhaust manifold to see if there was spark but could not get anything. Not sure if that method even works.

 

[Ford851]

Having trouble following.
Do you have a 3 or 4 post starter solenoid?
Is there a two post terminal strip in the circuit.

With the hot lead from the battery going to one side along with one side of the switch. Then the other side of the switch goes to the side of the terminal strip where the coil is attached? This allows 12 volts to the coil only if the key is on.

Not to go to far afield but read on another site that some of the Napa IC14sb coils are now made in China and have been bad. I don't know how true this is but you might want to check it out. You may have wired everything correctly and just gotten a bad coil. By the way you did remove the resistor?

Please post back on the solenoid.

See ya,
Ford851

 

[deerefan]

Having trouble following.
Do you have a 3 or 4 post starter solenoid?
Is there a two post terminal strip in the circuit.

With the hot lead from the battery going to one side along with one side of the switch. Then the other side of the switch goes to the side of the terminal strip where the coil is attached? This allows 12 volts to the coil only if the key is on.

Not to go to far afield but read on another site that some of the Napa IC14sb coils are now made in China and have been bad. I don't know how true this is but you might want to check it out. You may have wired everything correctly and just gotten a bad coil. By the way you did remove the resistor?

Please post back on the solenoid.

See ya,
Ford851

It is a 3 post solenoid. You are correct about the switch also. Is there any way to test the coil? I tried a couple unproven methods but never got spark (grounded to exhaust manifold, put spark plug in coil wire).

 

[Ford851]

Here some excerpts from another thread that I've been following. This guy couldn't get spark out of his plug wires, but they talk a lot about coils. sound guy gives most of the advice plus a few others. Hope this helps. The thread is "No Spark to plugs..please read and help" by nj82tj

This thread is recent. Look on page 3 and upward.
Instead of having to crank your tractor everytime to check for spark, disconnect your neg points wire from coil and just use a jumper wire to ground. Just make sure your rotor is lined up to one of your plug wires and touch and release your jumper to act as your points. I also have seen rotors leak to the dist shaft.

soundguy"
If it is a napa coil MADE for 12v native use.. it's primary winding will contain the correct number of turns of wire of the correct diameter to produce correct primary circuit resistance ( usually in the 3-3.5 ohm range )

soundguy:
primary current is what you arecontrolling when you add a resistor. primary curent will need to be controlled to make sure the coil can disipate heat ( wattage determines this ).. and to keep points happy. points surface area determines what amperage they can conduct and their design dictates how much wattage ( heat 0 they can disipate. you will sometimes se ventilated or peirced points.. etc. ( dwell or duty cycle effects all this ).

most points like about 3.5a on average primary current.

oil potted coils disipate heat better than epoxy or tar potted coils, or solid coils.

condensor is just a switch debouncer.. points are just a switch. condensor provides a path for current flow at the moment the points open to prevent arcing and burning.. oncve points open far enough so that no arcing is present, the condensor has done it's job.. it's just a quick stopgap.. without a condensor ( open ).. the points would pit and burn quickly.

soundguy:
use a test lamp inline with the coil.. crank over.. if it blinks.. points are not shorted.( thus condensor is not shorted )
if it stays lit, points are shorted. ( closed up or condensor short.. or feed thru insulator shorted )

if it kinda blinks but no or weak spark.. check breakers for arcing and pitting. this could be a sign of OPEN condensor. you can test a condensro with an analog ohm meter set to 1x scale.

short pig tail to cond body.. put leads on tail and body.. ohms should got to 0, then swing to infinite.

soundguy:
I agree with DR dave. when you see a system that tries to start the moment you let off the starter.. it usually menas low power to the coil.

wow.. 8.5-9v atr the coil.. that's pretty low!! I would think it should be more like 10v.

double check your wireing to make sur ethere are no hidden resistor or resistor wire feeding it.

here another test you can do.

got a spare battery? hotwire the coil from a spare car battery.. or lawnmower battery.. ie.. ground the battery to chassie, and run hot wire to coil primary.. now crankt he tractor over.. see if spark is hotter and she starts. post back

 

[deerefan]

It is a 3 post solenoid. You are correct about the switch also. Is there any way to test the coil? I tried a couple unproven methods but never got spark (grounded to exhaust manifold, put spark plug in coil wire).

Thanks for the advice guys. I will try these methods and post back. As you can see, I am not very familiar with points style ignition. The 2 cars I am restoring both came to me with points and I converted them to electronic ignition (hei). By the time I started driving in 1994, points were not the ignition of choice. Its funny something that seems very simple can baffle me so easily!!!

 

[Ford851]

Just remember that the points are nothing more than a switch that are opened and closed by the rotation of the distributor shaft. The point are on the primary side of the coil (low voltage side). When a magnetic field is built up in the primary and then collapsed by the opening of the points it induces a voltage onto the secondary coil winding. The secondary has many more winding on the its coil and produces a much higher voltage output to the distributor. The distributor then disperses the voltage to each plug. Again the shaft inside the distributor is also turning the rotor which touches each spark plug outlet on top of the distributor. The spark should arrive at the plug as the piston reaches top dead center (TDC) on its respective compression stroke. This ignites the fuel and sends the piston down. Thus turning the crank. Getting all this time correct is the key. Hope this helps. Not trying to preach just putting out there what I understand to be true. Others, may disagree. We'll soon find out.

The capacitor is connected to the points to take the charge when the points open so there is a path for the current to go to instead of arcing across the points and pitting them if your curious.

Best regards,
Ford851