The Ford Barn

Terry, NJ · 06-08-2012, 02:28 PM

I've replaced the points, coil, coil wire, new cap and I've been all over it with a ohm meter. The ohm meter gives an "open" when the points are open and a "closed" when the points closed. I checked the gap of the points and re gaped them to .015. When they're closed, I get a continuity reading between them. When they're open, I get nothing. Everything seems fine on the low tension side of the coil. I reversed the connections to the coil, thinking maybe that would make a difference, but it didn't. Everything appears correct on the high tension side, yet no spark! However, the coil is not grounded, it seems like it should be. What am I overlooking?
Terry

ford1 · 06-08-2012, 03:13 PM

condensor? will the coil spark when you open and close the points manually?

700rpm · 06-08-2012, 03:16 PM

Your points should be about .020.

When you turn your key on and scratch the distributor end of your ignition cab;e on a head nut, do you have spark? If yes, then the problem is in the distributor. If no, then the problem is in your switch.

Pilotdave · 06-08-2012, 03:20 PM

Starting with the points closed, are you getting a spark at the points if you use a small screwdriver to open them? Similar to ford1's question.....if you ground the high tension lead and open the points, are you getting a spark to ground? Color? What do you mean by saying that the coil s/b grounded?

jkeesey · 06-08-2012, 03:31 PM

Your points should be gapped 18-22. 18 on new points so when they wear they are still in spec. Your coil is grounder to your distributor. That's where the spark comes from when the points close it grounds the coil and sends spark out the coil wire. Remove your coil wire and place it close to a ground and with the key on manually open and close the points with a peice of wood or plastic and you should get a spark.

Tom Wesenberg · 06-08-2012, 03:51 PM

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One end of the coil secondary is the hot wire that goes to the plugs. The other end of the secondary windings is soldered to one of the primary posts, so it grounds through the primary circuit, and the coil body does NOT need to be grounded.

The spark is generated by the rapidly collapsing magnetic field when the points OPEN. The condenser forms a tuned circuit with the primary winding and helps to maintain the high voltage for a longer period of time. The condenser also helps to keep the points from arcing when they open. When the points close the magnetic field is built up around the coil windings again and the cycle repeats for each cam lobe.

To check for spark I just hold the coil wire about 1/4" from a head nut while I reach the starter switch and push the rod down with the key on. If no spark, then I remove the dist. cap and stop the engine with the points open. Turn the key on and short the points with the blade of a screwdriver (off-on, etc.) If I now have spark at the coil wire, then I know I need to clean the points contacts. If I still have no spark, then I need to work back and see where the 6 volts dropped off. Sometimes it's poor contacts in a repro switch, as happened to me a few years ago on my 28. Sometimes it's the repro switch contacts touching the gas tank and grounding out, as has also happened to me about 10 years ago on my 29 Tudor.

Terry, NJ · 06-09-2012, 06:45 AM

Gee Tom, ever think about being a teacher? In a few sentences, you've answered some questions that I've been scratching my head over for a long time. I suspected a "Internal" ground for the secondary windings but didn't ever get a ohm meter on it.
So, I got a weak spark at the head nut. The spark won't jump more than 1/8 ". Usually a spark will jump 3/4" with no trouble. Also, the spark is frequent , but intermittent. Maybe this is caused by small, slight movements of my hand, I can't say for sure. But the spark is not getting out to the plugs.
Terry

Quote:

Originally Posted by Tom Wesenberg

One end of the coil secondary is the hot wire that goes to the plugs. The other end of the secondary windings is soldered to one of the primary posts, so it grounds through the primary circuit, and the coil body does NOT need to be grounded.

The spark is generated by the rapidly collapsing magnetic field when the points OPEN. The condenser forms a tuned circuit with the primary winding and helps to maintain the high voltage for a longer period of time. The condenser also helps to keep the points from arcing when they open. When the points close the magnetic field is built up around the coil windings again and the cycle repeats for each cam lobe.

To check for spark I just hold the coil wire about 1/4" from a head nut while I reach the starter switch and push the rod down with the key on. If no spark, then I remove the dist. cap and stop the engine with the points open. Turn the key on and short the points with the blade of a screwdriver (off-on, etc.) If I now have spark at the coil wire, then I know I need to clean the points contacts. If I still have no spark, then I need to work back and see where the 6 volts dropped off. Sometimes it's poor contacts in a repro switch, as happened to me a few years ago on my 28. Sometimes it's the repro switch contacts touching the gas tank and grounding out, as has also happened to me about 10 years ago on my 29 Tudor.

1931 flamingo · 06-09-2012, 07:01 AM

What's your voltage?? At the batt, junction box,points.
Paul in CT

Purdy Swoft · 06-09-2012, 07:46 AM

Modern points???

pat in Santa Cruz · 06-09-2012, 08:28 AM

the last time I experienced the same problem, it turned out to be a defective brand new coil. That was 2 months ago. Apparently a bad batch was sent out to several suppliers. I got one from FS, which they acknowledged they had been having trouble with the recent batch and replaced promptly.

Terry, NJ · 06-09-2012, 10:19 AM

The coil is a Chinese made replacement for a Ford 8N tractor (4cyl, 6V + ground) I'm thinking of swapping it with the coil from the coupe and see what happens. Because it was new, I figured I had that base covered.
Terry

Quote:

Originally Posted by pat in Santa Cruz

the last time I experienced the same problem, it turned out to be a defective brand new coil. That was 2 months ago. Apparently a bad batch was sent out to several suppliers. I got one from FS, which they acknowledged they had been having trouble with the recent batch and replaced promptly.

Terry, NJ · 06-09-2012, 10:20 AM

No, they're NOS

Quote:

Originally Posted by Purdy Swoft

Modern points???

06-08-2012, 02:28 PM	#1
Terry, NJ Senior Member Join Date: May 2010 Location: Bucks Co, Pa Posts: 3,740	Still no spark I've replaced the points, coil, coil wire, new cap and I've been all over it with a ohm meter. The ohm meter gives an "open" when the points are open and a "closed" when the points closed. I checked the gap of the points and re gaped them to .015. When they're closed, I get a continuity reading between them. When they're open, I get nothing. Everything seems fine on the low tension side of the coil. I reversed the connections to the coil, thinking maybe that would make a difference, but it didn't. Everything appears correct on the high tension side, yet no spark! However, the coil is not grounded, it seems like it should be. What am I overlooking? Terry

06-08-2012, 03:13 PM	#2
ford1 Senior Member Join Date: May 2010 Location: oroville ca. Posts: 1,554	Re: Still no spark condensor? will the coil spark when you open and close the points manually?

06-08-2012, 03:16 PM	#3
700rpm Senior Member Join Date: May 2010 Location: Portland, Oregon Posts: 5,906	Re: Still no spark Your points should be about .020. When you turn your key on and scratch the distributor end of your ignition cab;e on a head nut, do you have spark? If yes, then the problem is in the distributor. If no, then the problem is in your switch. __________________ Ray Horton, Portland, OR As you go through life, keep your eye on the donut, not the hole.

06-08-2012, 03:20 PM	#4
Pilotdave Senior Member Join Date: Oct 2010 Location: Grafton, MA Posts: 1,226	Re: Still no spark Starting with the points closed, are you getting a spark at the points if you use a small screwdriver to open them? Similar to ford1's question.....if you ground the high tension lead and open the points, are you getting a spark to ground? Color? What do you mean by saying that the coil s/b grounded?

06-08-2012, 03:31 PM	#5
jkeesey Senior Member Join Date: Apr 2011 Location: Glenmoore Pa Posts: 1,644	Re: Still no spark Your points should be gapped 18-22. 18 on new points so when they wear they are still in spec. Your coil is grounder to your distributor. That's where the spark comes from when the points close it grounds the coil and sends spark out the coil wire. Remove your coil wire and place it close to a ground and with the key on manually open and close the points with a peice of wood or plastic and you should get a spark.

06-08-2012, 03:51 PM	#6
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: Still no spark Sponsored Links (Register now to hide all advertisements) One end of the coil secondary is the hot wire that goes to the plugs. The other end of the secondary windings is soldered to one of the primary posts, so it grounds through the primary circuit, and the coil body does NOT need to be grounded. The spark is generated by the rapidly collapsing magnetic field when the points OPEN. The condenser forms a tuned circuit with the primary winding and helps to maintain the high voltage for a longer period of time. The condenser also helps to keep the points from arcing when they open. When the points close the magnetic field is built up around the coil windings again and the cycle repeats for each cam lobe. To check for spark I just hold the coil wire about 1/4" from a head nut while I reach the starter switch and push the rod down with the key on. If no spark, then I remove the dist. cap and stop the engine with the points open. Turn the key on and short the points with the blade of a screwdriver (off-on, etc.) If I now have spark at the coil wire, then I know I need to clean the points contacts. If I still have no spark, then I need to work back and see where the 6 volts dropped off. Sometimes it's poor contacts in a repro switch, as happened to me a few years ago on my 28. Sometimes it's the repro switch contacts touching the gas tank and grounding out, as has also happened to me about 10 years ago on my 29 Tudor.

06-09-2012, 07:01 AM	#8
1931 flamingo Senior Member Join Date: May 2010 Location: new britain,ct 06052 Posts: 9,390	Re: Still no spark What's your voltage?? At the batt, junction box,points. Paul in CT

06-09-2012, 07:46 AM	#9
Purdy Swoft Senior Member Join Date: May 2010 Location: Alabama Posts: 8,099	Re: Still no spark Modern points???

06-09-2012, 08:28 AM	#10
pat in Santa Cruz Senior Member Join Date: May 2010 Location: santa cruz, calif Posts: 2,011	Re: Still no spark the last time I experienced the same problem, it turned out to be a defective brand new coil. That was 2 months ago. Apparently a bad batch was sent out to several suppliers. I got one from FS, which they acknowledged they had been having trouble with the recent batch and replaced promptly.