positive side of coil

[65truckowner]

Probably a dumb question but does the positive side of the coil stay hot all the time. I have 12 volt wire when cranking and a 12 volt wire when key on. Cant get the engine to start so I was trouble shooting and checked the positive side of the coil and had no power with the key on Unhooked the negative side of the coil then the positive side was hot. The points where closed. Turned the engine until the points opened and hooked back up the negative side and the positive had power. Is this right?

[lutronjim]

Sounds right to me. Points ground the coil and I would expect you would read 0 on + side. While they are closed the coil saturates and when they open the condenser 'oscillates' to get a hot spark. Bad condenser gets you a almost useless spark on plugs - replace condenser.

[67 Burb]

Originally Posted by lutronjim

Sounds right to me. Points ground the coil and I would expect you would read 0 on + side. While they are closed the coil saturates and when they open the condenser 'oscillates' to get a hot spark. Bad condenser gets you a almost useless spark on plugs - replace condenser.

The function of a condenser in a coil ignition system is to reduce the spark at the contact points as they open in the distributor and thus minimize burning and pitting of the points. Arcing is caused by the effect of self induction in the coil as the points interrupt the flow of current. (Courtesy of: "Technical Talk – Ignition Condensors by Alan Hale". It doesn't "oscillate".

[65truckowner]

Thanks for the input.