On the right track..No spark

I finished putting my 1941 9N back together. Front Distributor 6 volt. I do not get a spark. Engine cranks fine. I cleaned the spark plugs, checked the gap. I inspected the distributor cap and found two of the posts were worn so I replaced the cap. I have a full charge on the batt. 6.32 volts and I get the same at the top of the "square can" ingition coil. Is there a way to test the coil on the bottom side at the sping the tab? If so what are the specs? The tractor ran fine before I pulled the sheet metal off to clean and paint? I have double and triple checked the wiring and its correct. Any pointers or suggestions would be great.

Thanks
Scott
 
Scott........iff'n yer reading battery volts at the top of the squarecan ignition coil, yer points are OPEN. Iff'n yer points were closed, the "infamous ballast resistor" would drop the coil volts to about 3-volts. ...but... you need the points to OPEN to create yer sparkies.

You do know ittza 2-bolt, 15-min job to remove the weird 4-nipple frontmount to change and adjust the points (0.015") on the kitchen table don't you??? Just un-snapple the capple and letter dangle. Installation is a reversal of the removal ...except... finger start yer 2-bolts and then install yer rotor and gently rotate yer OFF-SET dizzy drive tang until it drops into the OFF-SET camshaft drive slot. Now tighten yer 2-bolts and re-snapple yer capple. Simple, eh?

Remember to "polish" the INVISIBLE corrosion from between the points after installation. I use a $1-bill. You can use a torn strip of HEAVY brown paper grocery sack iff'n you want. Just clamp between the closed points after adjusting (0.015") and pull. Simple, eh. .........Dell, yer self-appointed sparkie-meister
 
" I have a full charge on the batt. 6.32 volts and I get the same at the top of the "square can" ingition coil. "

That's only half the story......what do you get w/ the points closed?

Assuming that the bushings & advance weights are ok, & that you have correct voltage to the coil, the most common electrical failure (no spark, weak spark) points on the frontmount are:

1. The insulator under the brass concave head screw.

2. The insulator at the end of the points where the copper strip attaches.

3. The copper strip is broken or grounded to the plate.

4. The condenser wire grounding.

5. The pigtail/tab not making contact.

6. Incorrect positioning of the spring clip on the plate causing the pigtail to ground.

7. Incorrect seating of the coil on the distributor due to a loose bail or no gasket; the coil must not move at all.

8. Water/moisture inside the cap due to gasket failure or the absence of a gasket.

9. Dirty/corroded/incorrectly gapped points

10. Burned rotor, cracked/carbon tracked cap.

Unless the coil is cracked or shows a dead short, chances are it's fine; square coils rarely fail cold. Pull the distributor & do a continuity check.

First, make sure your meter/light works (don't ask....)

Next, 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. Then, check the gap at .015 on all 4 lobes.

Now, follow these steps:

1. Coil off, cap off, points open. One probe on the brass screw & the other on both sides of the open points. On the side closest to the cam, you should have continuity. Not on the other side! If you do, you will also have continuity everywhere because the points are grounded.

2. Coil off, cap off, points open. One probe on the brass screw & the other anywhere on the body of the distributor. You should have no continuity! Now, rotate the tang on the distributor....as the points open & close, you have continuity (closed) and lose it when they open.

3. Coil on, cap off, points open. One probe on the lead on the top of the coil, the other on the cam side of the open points. You should have continuity!

4. Coil on, cap off, points open. One probe on the lead on the top of the coil, the other anywhere on the body of the distributor. You should have no continuity!

At this point, I just put the distributor, coil & cap all back on the tractor as a unit. The reason I do this is because it is real easy to get the cap or coil mis-aligned trying to put it back together one piece at a time & the result is something gets broken or you get a ‘no spark’ problem.

It's possible to put it back on wrong & break it. Look at the slot on the end of the cam shaft. What ever angle it happens to be, turn the distributor tang to match it. Make sure you can tell the wide side from the narrow side on both the cam & distributor! (close counts) Then place the distributor on the front of the engine, gently push it in place & slowly turn the distributor body until you feel the tang slip into the slot. Rotate the distributor body until the bolt holes line up. Then, hand tighten the two bolts until the distributor body is flush w/ the timing gear cover.

Finally, double check your firing order & plug wires. It’s 1-2-4-3, counterclockwise. It’s very easy to cross 3 & 4.

Post back w/ results & any other questions.
50 Tips
 
Thanks Bruce and Dell!
While waiting for a reply I took the can and cap off and looked at the points. I can see a burned spot on the points and it does not appear they are opening and or closing when I crank the engine. On my next day off, I'll pull'er apart take a closer look and clean, adjust and replace if needed. Thanks for the pointers.

Scott
 
Quality parts are critical to longevity. Having learned the hard way, I most always use Blue Streak brand points. They are made by Standard parts & available at many auto parts stores. (frontmount points also fit a 48 Ford as I recall) Beware of sticker shock: $16-18 a set. My next choices are Wells or Echlin. Look for a brown rubbing block. Unfortunately, many folks have experienced problems w/ points made by Tisco, Sparex, A&I Products and any TSC ignition parts..

Correct points installation & gap is also important. Make sure the blade is at a perfect right angle to the points & you want to feel just the slightest bit of drag when you pull the blade through the points. Make sure the blade is clean & that you dress the new points by running some card stock or a piece of brown paper bag through them. Gap is .015 on the frontmount on all four lobes of the cam. Make sure the points align correctly. Proper alignment is also critical to longevity. Look at the points when they are closed; both sides should mate evenly. And don't forget the cam lube!
50 Tips
 
I just wanted to post back and say thanks for the help. I replaced the points and condenser and put it all back together and it fired right up. If anyone wants I have the new part numbers for NAPA ECHLIN points and condenser.

Scott
 
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