No spark past coil

Got a 1952 8n with the new house.
I am new to tractors.

Ok so 1952 side mount still
6v.new battery, coil, plugs, plug
wires, dist cap rotor and points.

I am still not getting spark to
the plugs. Am getting 6.4 volts
to the coil but do not have a
test light. Get no spark from
plugs or coil cable. The coil i
put in is not internally
resisted. Did i get the wrong one
and need one with built in
resistor. Or what else am i
missing?

Welcome to the forum!

What is the voltage on the distributor side of the coil, points open
and with the points closed? You should get battery voltage there
when they are open and zero when they are closed.

If that voltage stays at battery voltage, the points are not closing,
or they are not making a good electrical connection.

If it stays at zero, they are not opening or you have a short to
ground somewhere. The feed through the side of the distributor
is one possibility, as is the copper strip inside the distributor.

Sometimes (more often than not) new points come with an invisible coating to protect them from corrosion. The coating will prevent them from conducting. I use a burnishing tool to clean the coating off. If you don't have one of those you can use a piece of brown paper bag, card stock, or a piece of cardboard from a cereal box. Just put it between the contact points and rub back and forth a few times should do the trick.

later
deano

Confirm that you have voltage to the coil. Battery voltage, points open. About half that if the points are closed.


Do you have battery voltage across the points when they are open? (with the points open, put one probe on one side of the points & the other probe on the opposite side of the points) Verify the gap on the points at .025. Then, dress the points by running a piece of card stock or brown paper bag through them. New points sometimes have an anti-corrosive dielectric coating on them & old points can corrode or pick up grease from a dirty feeler gauge or excessive cam lubricant. (I always spray my feeler gauge blade off w/ contact cleaner.) Make sure you have voltage across the points, as in past the insulator on the side of the distributor. That is a very common failure point on sidemounts, along w/ the attached copper strip. It's hard to find a short there because it is usually an intermittent . So 'wiggle' the insulator & the copper strip a bit when you are doing your checking. If you find the short there, the Master Parts catalog lists everything you need on page 154. You can make the strip and you could also make the insulators as well. But, somethings are just easier & in the long run cheaper to buy. Get the strip, 12209, screw 350032-S, 12233 bushing & 12234 insulator & just replace it all.


If you just replaced the rotor & lost spark, put the old one back in. Insure that the rotor fits firmly on the shaft & that the little clip is there. Make sure the distributor cap is not cracked, doesn?t have gouges in it from the rotor or brass shavings & doesn't have carbon tracks. Check continuity on the secondary coil wire. Make sure it is firmly seated in both the cap & the coil. Next, remove the secondary coil wire from the center of the distributor cap, turn the key on & crank the engine while holding the end of the wire 1/4" from a rust & paint free spot on the engine. You should see & hear a nice blue/white spark. If not, you have a bad coil or condenser. Just put the old condenser back in to eliminate that as a possibility.



Post back w/ results; I'll be interested in what the problem was.
75 Tips

Thanks guys in the morning i will clean and check the points and copper strip.

I have not had the tractor running yet and have only replaced all these parts trying to figure this out. Btw i have also replaced the solenoid

What diagnostics did you run to determine if those parts were defective?
75 Tips