1952 8N, Negative or Positive

macattack

New User
This message is a reply to an archived post by JBinNY on October 07, 2008 at 10:35:52.
The original subject was "1949 Ford 8N wont start no spark... advice needed".

OK, I too have an 8N, no spark, Battery new, 6 volt. Assuming have a negative ground, 'cause the coil I started with was attached to the points on distributor to coil's negative screw. Other ways to tell for sure of determining ground? and What damage could be done if wrong. m
 
The coil doesn't care as much as the battery does. And the generator.

Is the positive battery cabled attached to the chassis of the tractor or to the solenoid?

"What damage could be done if wrong"

Depending on what all you've done to it w/ the polarity reversed, it could let the smoke out of the v/r.

But polarity reversal isn't going to result in no spark. It will result in no charge.

Do you have battery voltage across the points when they are open? 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 guage 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 carbon tracks. Check continuity on the secondary coil wire. Make sure it is firmly seated in both the cap & the coil. In fact, replace it temporarily w/ a plug wire. 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.
75 Tips
 
(quoted from post at 13:23:52 06/14/16) The coil doesn't care as much as the battery does. And the generator.

Is the positive battery cabled attached to the chassis of the tractor or to the solenoid?

"What damage could be done if wrong"

Depending on what all you've done to it w/ the polarity reversed, it could let the smoke out of the v/r.

But polarity reversal isn't going to result in no spark. It will result in no charge.

Do you have battery voltage across the points when they are open? 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 guage 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 carbon tracks. Check continuity on the secondary coil wire. Make sure it is firmly seated in both the cap & the coil. In fact, replace it temporarily w/ a plug wire. 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.
75 Tips

Thanks Bruce, I put the battery in, so grounded the negative. Then I read about the reverse polarity. That's where the tip to check the coil hookup came in, so still thinking that negative is the way it was set up originally. m
 
No, it came from the factory positive
ground.

If the amp meter shows a charge, leave it
alone. If it won't charge, see tip # 23.

But, as I said, polarity reversal won't
result in no spark
75 Tips
 

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