The Stovebolt Site Forums The Shop Area The Electrical Bay Spark on my 37 ? Ignition problem

Ok, have a 37 1/2 ton stock condition. Have points set at .020 I can open them up with a pencil and get spark with the cap and rotor off. I don't have spark at the plugs when back together. I don't have spark when turning over with starter. I've have spark on the coil wire coming out out of coil. Power on both + and - of the coil. I have power into the points and also at condenser.
I need help would like to get it running before snow fall. I installed new battery, too.
Thanks

Thanks for any input

Check your rotor button and distributor cap for corrosion on the brass contact surfaces. If those are good, check the plug wires. Good luck with your project.

Spark at the points when opened manually.

Spark out of the coil when points opened manually or when engine cranked?

Obvious answer is a cap/rotor problem. Shorted rotor, cracked cap, missing center contact.
Wrong cap/rotor combination.

Second possibility - if spark at the coil when points are opened manually but not when cranking - wiring is wrong/bad. Power to the ignition is shut off during cranking.


obscure possibility - distributor shaft not turning

Wiring coming out of ignition might be problem? I have power when key is turned on through coil into distributor and points spark when opened with a pencil. Push foot starter , distributor shaft turns with cap off but no spark at points. What should the inside of cap look like where rotor button rides?

This is off of a mopar but the GM is similar. I just replaced the cap on my '38 & the center nub isn't as pronounced as the one in this picture.

Ignition sw on you get spark when opening the points by hand, but no spark at the points when cranking the engine?

put a volt meter on the distributor input and read it when you open and close the points by hand. Then read it while the engine cranks. If the voltage goes way down, take the same readings on the input side of the coil. Same thing? take the same readings at the hot side of the ignition switch.

If the voltage drops off at the dist. when cranking but is good going into the coil, you could have a 12V coil in a 6V system, or a wrong resistor.

Thanks guys. It is purring like a kitten. I charged the new battery to full. Cleaned the points one more time, cleaned the button in the top of the cap. My uncle Perry, and dad stopped into help. Resistance test shows a 6 volt coil. New fuel, new battery, antifreeze, runs and idles great. Now I have to get her to stop. No brake pedal at all. She has been sitting for 13 years.
Thanks for all the replies.