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Subject: No spark

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Ken    Posted 06-04-2017 at 08:22:18 [URL] [DELETE]        [Reply] [Email]  
  • No spark
  • Hi All,

    I've been working on getting my "52" Ford 8n running. I have relpaced ALL the electrical components and thought I was finally ready ( after 2 years) to fire her up. My problem is I have no spark leaving the distributor. I have 12.38v leaving the coil but nothing going to the plugs. Figured the problem might be the points, but double checked the gap & it's set at .025. For the life of me I can't figure out why I can't get spark to the plugs, can anyone help me with this, I'm at my whits end.

    Bruce (VA)    Posted 06-04-2017 at 08:47:58 [URL] [DELETE]        [Reply] [Email]  
  • Re: No spark
  • 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. 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.

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

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