12 volt coil

[Animal]

How long should you expect those square can, land of almost right coils to last?

 

[souNdguy]

With proper ballast and primary current, I'd expect them to last 'a long time', if they make it past high early failure rate / infant mortality limits.

 

[old]

That is one of those pot luck things. It might last a day or it might last 10 years all depends on how lucky you get

 

[HCooke]

I have seven 9/2/8Ns with front mount distributors. I have never experienced a front mount coil failure (knock on wood).

 

[Animal]

When I put this on new I used the OEM resistor and a ballast resistor and it started and ran well. It sat over winter and would not start unless pulled and it did not seem to have much power, weak fire. I pulled the ballast resistor and just ran off the OEM resistor and it did well last summer. This spring was the same thing, would fire but would not run, as a matter a fact it would backfire like it had a wire crossed, and then when it did start only ran on two cylinders. I figured I had fouled the plugs, put in new plugs and it would not hit a lick. So I pulled the dizzy and found the points were too close, but still breaking. I cleaned the points but found the cam was too warn to get to the correct gap. So I installed a petronix ign, by passing the oem resistor and installing the correct ballast resistor for the petronix unit. Still no fire. I think it has to be my coil. One of the local gurus on N series tractors here said that the OEM coils would last forty years, but these rice coils are real hit and miss, and he agrees that it is the coil.

 

[souNdguy]

Its rare to have e can wore too far to open points. Usually its junky points.

In any case, instead of guessing, you can simply just check the coil...

Get a battery, condensor and some test leads, a spark plug, and setup as follows.

Hot to coil top

Coil flat tab to spark plug top, use short wire, good insulation.

Spark plug threads wired to bat ground

Coil spring wired to pigtail on condenser

Case of condenser wired to bat ground

Seperate wire from coil spring, heavily insulated, tap that against bat ground repeatedly, that's your points opening and closing, should spark at the plug when you pull that wire off bat ground. Condenser is across coil spring and ground, power to coil top.

That's as easy as it gets.

 

[greywolf224]

Animal since there is not much you can do to check a coil, as a preliminary test, ohm out from the ignition wire lug to the spiral spring on coil. Also from the ignition wire lug to the flat blade on coil.
You are checking for a dead short or an open circuit

Obviously Soundguys test is much better and will provide you with a true Go Nogo

 

[Animal]

You are right about junky points and while we are at it, what about those crappy condensors? That is another reason for the petronix set up, but trust me the cam was worn out. I am going to test the coil as you suggested, and thank you for all your help, I really appreciate it!!!

 

[souNdguy]

If the can was worn that bad, someone forgot to lube it/rubbing block like they should have..

 

[greywolf224]

Chris never could understand how the cam gets worn from a plastic rubbing block or even from the better quality points with the layered rubbing blocks.

Do the layered blocks have any metal fillers in them?

 

[Bruce (VA)]

" I cleaned the points but found the cam was too warn to get to the correct gap. So I installed a petronix ign, by passing the oem resistor and installing the correct ballast resistor for the petronix unit. Still no fire"


So you are counting on the EI to fix the worn cam?

I'm not sure about your specific unit, but some makers include a plastic magnetic cam sleeve-to-ignitor module gauge in the installation kit and further state that it should be adjusted to 0.030 inch. Variations will alter dwell & if too far off will not switch.
75 Tips

 

[JMOR]

(quoted from post at 07:53:03 04/06/15) " I cleaned the points but found the cam was too warn to get to the correct gap. So I installed a petronix ign, by passing the oem resistor and installing the correct ballast resistor for the petronix unit. Still no fire"


So you are counting on the EI to fix the worn cam?

I'm not sure about your specific unit, but some makers include a plastic magnetic cam sleeve-to-ignitor module gauge in the installation kit and further state that it should be adjusted to 0.030 inch. Variations will alter dwell & if too far off will not switch.
75 Tips

don't see any measurements, can't "know" if cam was worn out or not! Wouldn't ever say impossible, but never see even one worn out & believe very highly unlikely that I ever will.

 

[souNdguy]

How does a river cut a canyon. Time and friction. Get one spec of debris on the block, and its now a lathe. Dirty tools, dust, missing dizzy gaskets, 70 years, and abrasive particles. Soot is an abrasive. might even be some ozone in there

 

[JMOR]

(quoted from post at 08:10:27 04/06/15) How does a river cut a canyon. Time and friction. Get one spec of debris on the block, and its now a lathe. Dirty tools, dust, missing dizzy gaskets, 70 years, and abrasive particles. Soot is an abrasive. might even be some ozone in there

lobal warming did it!