no spark - 1951 8N

[cfb]

Hi, we replaced plugs, points, distributor cap and coil . don't get a spark at the coil.. Cranking is strong. What is my next troubleshooting step? thanks

 

[MasseyWV]

Did you also replace the condenser?

 

[Soundguy]

got power to the coil?

are points opening and closing electrically?

what type of coil you using?

have you put a test lamp in line with the coil primary?.. tells alot..

 

[cfb]

hi, I don't know, I'll ask my son.

 

[cfb]

re: soundguy's ?: yes we do have power to the coil. yes, points were opening an closing electronically. We bought a coil from NAPA. I'm not sure about the last question. I'll ask my son. I've been sitting with him periodically when he's had problems - mostly for my benefit and lend another set of hands/eyes. thanks

 

[Soundguy]

what was the coil number?

 

[J_J]

With power on, 12v or 6v to the coil plus terminal, ground the minus terminal momentary and remove the wire from ground, and see if there is spark.

If the coil is good, then I suspect the points are grounded and will never produce a spark.

A spark is produced by removing the ground path to a coil. The electromagnetic field built up in the power mode will collapse and therefore produce a spark.

If the points are installed correctly, when they open, the ground path is broken and the field collapses, producing a spark.

 

[cfb]

thanks again for all the responses.
yes, replaced the condensor. NAPA coil #IC14SB was used (no resistor needed).
A clarification, when I said yes to power to the coil - we put the volt meter on it and when turned the key on, it registered 12v.
also, I know the points were opening and closing, but my son says we know that manually, not electrically. how do we do see it electrically?
thanks JJ for your tip, we'll try that.
cfb

 

[J_J]

With no voltage applied, use ohm meter or continuity setting to verify the wire from the neg terminal to ground.

Should have continuity with points closed and none with points open.

The points provide a path for ground.

The condenser is there to help keep the points from arcing and pitting.

 

[David_Kb7uns]

Worked on a friends 8n one time and the mechanical advance had rubbed a hole in the insulation of the wire going to the points of the distributor.

David kb7uns