Ignition coil + or -

Unknown

I am replacing the coil on my 53 hornet. Which wire is positive? The wire comming from the distributor or the wire off of of the engine block? I want to be sure.. Thanks ...

J Spencer

the_vettguy wrote:

I am replacing the coil on my 53 hornet. Which wire is positive? The wire comming from the distributor or the wire off of of the engine block? I want to be sure.. Thanks ...

Positive to distributor, remember positive ground. Negative to Ignition switch.

Opposite connections for cars with negative ground, -- like 12volt systems.

Car would actually run hooked up backwards but may present ignition problems IE hard starting, misfire under load ??



Jim Spencer

Unknown

Rule of thumb is side to distributor that matches battery ground.

[Deleted User]

I've heard arguments that it doesn't matter, because the coil is just a transformer that doesn't really care what the polarity is across the primary windings.



BUT, i've noticed the exact same things J Spencer mentioned. If the distributor side of the coil doesn't match the polarity of the battery ground terminal - hard starts, weak sparks, and general malcontent.



Don't ask me how I found out the ill problems of incorrect coil polarity. I'll bet you can imagine for yourselves.



Mark

Park_W

A Delco training manual and another reference I have says that with the coil polarity incorrect, the spark voltage will be reduced about 15%. With our low compression Hudsons, that difference might never be noticed unless some other aspects of the ignition system are marginal. But try it on an engine with greater demand for a hot spark and you've got trouble. The reason the polarity matters is that the center electrode of the spark plug needs to be "negative" when the high voltage arrives there. Why? That center electrode metal is very hot, so it emits a lot of electrons, making it "naturally negative." By designing the system so the voltage arriving at the center electrode is also negative, the two effects add to each other, whereas if the system applied positive voltage there, the heat-produced negative voltage would subtract from the coil-produced voltage instead of adding to it. Ta Daaaaaa!

[Deleted User]

Park W wrote:

A Delco training manual and another reference I have says that with the coil polarity incorrect, the spark voltage will be reduced about 15%. With our low compression Hudsons, that difference might never be noticed unless some other aspects of the ignition system are marginal. But try it on an engine with greater demand for a hot spark and you've got trouble. The reason the polarity matters is that the center electrode of the spark plug needs to be "negative" when the high voltage arrives there. Why? That center electrode metal is very hot, so it emits a lot of electrons, making it "naturally negative." By designing the system so the voltage arriving at the center electrode is also negative, the two effects add to each other, whereas if the system applied positive voltage there, the heat-produced negative voltage would subtract from the coil-produced voltage instead of adding to it. Ta Daaaaaa!

I'm glad to finally have an explanation that I believe.



Nice to bring the practical and theoretical together.



Mark