No Spark - 6 Volt 1948

  Are your new plug wires of the solid-core, copper or steel type, or are they carbon-core resistor wires? 6 volt systems do not like resistor wires. 

BW 

Any more ideas?

Thanks!

I will check the voltage at the distributor and let you know.

Did a bunch of reading in the 1946 Audels Automotive, 1948 Motors manual, the Jeep maintenance manual and other old books on ignitions and coils.  

Also had a chance to check the capacitor MF.  Wow, I check about 8 capacitors some modern, some used and a bunch of NOS.  Readings all over the place from .18 to .28 mf also check the leak down on all of them.

Then I checked the primary and secondary on the 6 volt coils.  The NOS key coil was 2.4 OHMs on the primary and the secondary read around 7000.  The newer style block mounted coil read 1.2 x 4000

I have an old WWII consolidated Jeep repair manual that  has a series of test that I hope to run tomorrow.

So here is the update on the no spark issue:

- Replaced the 6 volt battery with New Optima 6 volt with 1,000 cranking amps.  (thought I was on borrowed time with my old 2009 Optima 6 Volt.  It does spin the motor a little faster (also had the store confirm the new battery was fully charged).

- Replaced the coil with a NOS Key Coil I tested last night.  

-- Confirmed that I have 6.3 volts at the distributor when the key is turned to "On".

- Replaced the Points and condenser (27mf on this NOS condenser - checked it last night)- both are tightly screwed to the base plate inside the coil.

- Set the points to about .024 (which might be out of spec)

- Replaced the coil wire (OHM checked to make sure is good - it is longer for a Key Coil and made with a steel core).

- Tightened the wire terminal on the distributor and confirmed it was not grounding to the distributor case. Confirmed there is no Ohm drop or voltage drop across this connection.

-- Confirmed that when the points are open the rocker arm of the points is not grounded.

-- Confirmed that when the points are closed the point are grounded.

-- Confirmed that there is no spark from the coil when cranking the engine.

-- Confirmed that with the ignition switch "ON" and the points closed (and the coil wire end 3/16 away from a grounded surface, that when you manually open the points there is no spark from the coil wire end to the ground surface.

-- Confirmed that here is continuity between the center of the distributor cap coil wire terminal and the graphite center post on the inside of the distributor cap.

Still no spark.

Any ideas?

Thanks

We have a running Jeep!

So in the end it was a real tail chaser! I added to any new parts, cleaned all the connections - it is hard tell for sure which was the exact issue.

But the final bit of trouble shooting was to take the primary's wire to the distributor and ground it against the block.  That did produce a spark.  Then repeat that with the secondary from the coil 3/16" away from the block at the sametime - No spark on the secondary from the NOS key coil.  Tried the same test with a block mounted coil (rewired everything and pulled the key coil and added in a key switch) and got a spark out of the secondary.  Reassembled everything.  Fired right up after 2 years of sitting.

Next problem was that the clutch was stuck to the flywheel.  Turned off the Jeep put it in reverse with the clutch pedal pressed in and cranked the motor.  It came free!  So, I took the Jeep for a spin around the block.  The Jeep pulled to the left at the first stop sign.  But after a few stops it went away completely.   Jeep stops straight.  Parking brake works (will hold the Jeep on the driveway hill).  Not leaking fuel.  So all seems good. The Jeep runs quiet like a sewing machine as it did years ago.

As for the NOS Key Coil - Hoping it just has some corrosion where the secondary exits the coil that just need to be cleaned up.  Will clean it up and do some testing 

Thanks for all the help!