Ford 8N having trouble starting -- many troubleshooting steps take -- suggestions?

[PorkChopsMmm]

Well, it's official, Soundguy jinxed it. (kidding)

EDIT: Still not starting. No spark at a plug wire that I pulled. I put a voltmeter grounded to the engine block and the coil and it is still 12V as before.

Ignore what I said about the voltmeter... I had a bad ground.

Soundguy -- sorry -- no lamp. I have been getting killed at work and just didn't have the time. Sitting here now I should have made the time. My next step is to go out and try and test the coil some more since the battery is charging.

Here are pictures that I took BEFORE I installed the distributor assembly.

Old busted breaker plate:

New breaker plate (sorry for the angle of the shot):

Inside of the distributor:

New breaker plate installed with closed points:

Open points with .015 shim:

 

[Soundguy]

4v on top of coil?

lets refresh some stuff.

12v system right?

i think i recall you saying it was a 2.5 ohm 12v coil.

you should only be running the oem ballast ressitor.. the 3 terminal one behind the dash.

you should be showing more like 8-10v on the top of the coil with points closed.

try this.. run a hot wire from battery to coil top.. just gator clip it.

this is putting full bat volts on coil.

see what ya got.

 

[PorkChopsMmm]

Thanks Soundguy. I had a bad ground on my voltmeter. When I re-situated the ground to a completely different part of the engine it registered 12V+. Cranked it a bunch more and still no dice. I think I am going to call a local tractor mechanic that someone told me about. He is supposedly familiar with 8N's and will come out to my house.

That being said, I will go gator clip from the battery to the coil to see if there is any difference.

 

[Soundguy]

well.. that new info means soemthing different.

if ti stays 12v at the top of the coil all the time with no change.. like dropping to 8/10 thenthe points are not closing....

 

[Soundguy]

or the coil is not setting correctly on the dizzy..

 

[Soundguy]

hers's how you can test the coil

take it to your bench.. get a 12v battery and some gator clips and one of your condensors.

wire battery hot to top of coil.. wire battery ground to the body of the condensor. wire the pig tail of the condensor to the pigtail spring on the bottom of the coil

wire a spark plug top connector to the flat tab spring on the bottom of the coil

wire the threads of the plug to battery ground.

now hook a gator clip to that pigtail spring on the bottom of the coil.

when you take the other end of that wire and touch and pull it back from the body of the condensor, the spark plug should fire. keep touching it and releasing it in fast succession should make the plug fire repeatedly. of course use some insulated tool to hold that gator wire clip.. not your bare hand. maybee use a paint stir stick with the gator clip wire taped to i so you can just repeatedly tap it.

each time you touch it you are making a connection thru the primary of the coil to the battery..like whenthe points close.. when you release the connection, it's like the points opening... the condensor is a switch debouncer, essentially.. a lil more complicated than that.. but a good enough explanation.

 

[PorkChopsMmm]

Soundguy. Very good test tip. You should feel good about that -- I asked at my local New Holland dealer and another repair shop and both places just responded with "you just have to test it on the tractor".

Let me tell you what I just saw and then if you think I should I will pull the coil and give it a test.

I measured the voltage at the 3 terminal OEM ballast resistor -- top lug always had power and with key off both bottom lugs did not. Turn key on and both bottom lugs get power. I measured the key switch and it behaved as expected -- one terminal always had power and when the key was off the other did not, flip the key and the previously unpowered terminal got voltage.

or the coil is not setting correctly on the dizzy..

I am wondering about this -- not the coil itself but the tab on the front of the coil that gets close to the rotor when it spins. I have heard the tab needs to be bent a certain way but I can't find pictures that verify how it should be situated. It definitely isn't touching the rotor -- there is a gap there.

 

[Soundguy]

the way the wireingf works is this.

top post is hot. key switch is connected between top post and one of the lower post. other lower post is connected to the top of the coil.

coil connections on the bottom are:

a flat tab and a curly pig tial spring.

the flat tab is the secondary high voltage tab. it should be parallel to the bottom of the coil.. it rides a nub on the top of the distribuitor cab. that nub is a metal post that goes thru, to the outter top center of the cap where a carbonized nub inside the cap is a contact point for a springy flat tab on the rotor..

the pig tail is the other end of the primary ( top of coil is one end as well ).. and the pig tail sets inthe brass concave head screw, and ultimately is connected to the moving section of the points and the pigtail of the condensor.

 

[sd455dan]

Soundguy. Very good test tip. You should feel good about that -- I asked at my local New Holland dealer and another repair shop and both places just responded with "you just have to test it on the tractor".

Let me tell you what I just saw and then if you think I should I will pull the coil and give it a test.

I measured the voltage at the 3 terminal OEM ballast resistor -- top lug always had power and with key off both bottom lugs did not. Turn key on and both bottom lugs get power. I measured the key switch and it behaved as expected -- one terminal always had power and when the key was off the other did not, flip the key and the previously unpowered terminal got voltage.


I am wondering about this -- not the coil itself but the tab on the front of the coil that gets close to the rotor when it spins. I have heard the tab needs to be bent a certain way but I can't find pictures that verify how it should be situated. It definitely isn't touching the rotor -- there is a gap there.

That's- not how most point style ignitions are made to function, usually a carbon button that is spring loaded presses the button against the center of the rotor which is generally brass molded into the plastic rotor...or the button is stationary and the rotor has a springy brass center that rides against the caps center contact either way the cap and rotor are in contact continually...

 

[Soundguy]

key on, points closed, on your 12v system, using a 2.5 ohm 12v coil and oem ballast resistor.. I'd expect anywhwere from 8-10v on top of the coil.

key on, points open... battery voltage at the top of the oil.

again.. a test lamp with one end hooked to battery hot, and the other to the top of the coil ( with oe coil wire off ), and spinning engine over, test lamp should blink...