6v vs 12v BD

Mr rrlund, no you didn"t plann to start a war and No war or attacks on my part, just getting tired of people putting out mis-information/unsubstantiated "facts" & misleading readers. Just trying to set the record straight, with real facts.
b&d will never find those "several thousand volts" more, because they do not exist. He keeps on beating his chest on the matter to try & save face, since beating his chest, making false claims & personal attacks is all he can do, because there is no way the he or anyone else can prove the extra "several thousand volts" exist, by simply reversing the primary wires. Just doesn"t happen. Can"t happen.

I dont have a dog in this fight and always just try to get along with EVERYBODY and respect them and expect the same in return and am NOT picking sides, but as an electrical engineer I CAN EXPLAIN (to best of my curent and I believe correct knowledge, still no warranty Im long retired and may be wrong) the firing voltage differences if a coil is wired at the correct polarity versus if not.

Im doing this as a public service to educate and HELP IF I SEE CONFUSION,,,,,,,, NOT FIGHT,,,,,,,NOT CHOOSE SIDES

NOTE IM NOT TALKING HERE ABOUT THE ENGINEERING DESIGN DIFFERENCE IN 6 VERSUS 12 VOLT COILS, I ALREADY THOROUGHLY EXPLAINED THAT SOME TIME BACK .....

IM ONLYYYYYYY GOING TO EXPLAIN WHY THE PLUGS WILL FIRE AT A DIFFERENT VOLTAGE IF THE COIL POLARITY IS REVERSED

Okay, any of you who are familiar with the desing of an electron tube like were used in radios etc years back you will know there is a HEATER under the cathode. The reason is its easier to emit electrons from a hotter (heated cathode) to a relatively cooler (Plate) area.

Soooooo the electron tip on a spark plug is muchhhhhhhhh hotter then the ground strap which has the mass of the engine block to which its heat is extracted. THEREFORE its much easier to emit electrons from the cooler tip to the relatively hotter ground strap ANDDDDDDDDDDDDDDDDD IF THE COIL IS AT THE CORRECT PLAORITY GUESS WHAT THATS THE ELECTRON PATH BUTTTTTTTTTTTT IF THE COIL POLARITY IS REVERSED THE ELECTRONS HAVE TO GO FROM THE COOLER STRAP TO THE HOTTER ELECTRODE TIP WRONGGGGGGGGGGGGGGGG

Some data Ive seen and data the late Duane Larson (Theoretical PHd Physicist) experimented and collected from scope traces of coil firings shows it takes like 3,000 to 4,000 volts less to fire the coil at the correct polarity then if the coil polarity is incorrectly reversed !!!!!

Sure, it will still fire at the wrong polarity but the system is more efficient (less heat losses) and the firing voltage is a few thousand volts less IF THE COIL IS USED AT THE RIGHT POLARITY.

For lay persons let me explain that the voltage it takes to arc jump current across a spark plugs gap is a function of 1) The gap distance and 2) The medium (fuel and compression) in which the arc takes place. A coil is NOT instantly at say 10,000 volts, when the field collapses its HV secondary voltage begins to ramp up n rise but onlyyyyyyyyyyyyy until high enough to arc jump current across the gap and noooooooo more

Okay, I cant explain here in a paragragh what can takes books and years of study to understand so if you are still confused to some research and study. Hopefully this helps lay persons understand why its best to use a coil at the corect polarity and why the firing voltage is less (maybe a few thousand volts) if used correctly .

God Bless yall n best wishes

John T Long retired Electrical Engineer but hey I still remember the basics and remember its easier to emit electrons off a hotter (tip) to a cooler (ground strap) and thats why coil polarity makes a difference

NOTE Im rusty on this and never too old to learn sooooooooooo if anyone has later accurate hard engineering data (not some Billy Bobs uneducated guess or opinion) that shows Im wrong PLEASE ADVISE AND HELP ME AND EVERYONE HERE BY BETTER EXPLAINING THE CORRECT ENGINEERING THEORY !!!!!!!!!!

Good job, JohnT.
I will point out that at cold start up the neg center electrode is as cold as the side electrode......when a good spark is needed the most, but.....take what we can get.
Those guys are not, however, debating your point as I see it, but rather whether wiring the coil +/- relative to the battery will allow the coil to produce several thousand extra volts or perhaps only a couple hundred extra volts and whether those extra couple of hundred come at the expense of "wrong" spark polarity. My view from the side lines.

I noticed a typo error above sorryyyyyy my bad..

Its easier to emit electrons from a hotter (plugs electrode tip) to a relatively cooler (plugs ground strap) is what I meant to type, my fingers get ahead of my old brain at times lol grrrrrr forgive my mistake.

The strap is much cooler then the hotetr tip of the plug so the coil needs wired so thats the direction of electron flow but if reversed polarity thE electrons have to flow from a cooler strap to a hotter tip WRONGGGGG

John T

Thanks for the kind words. FUN CHAT

If a tractor is wired Pos ground, the coils - receives ign switch voltage while its + wires to ground via distributor terminal and eventually the closed points. IE The coil polarity has to match battery polarity for most efficient ignition....

HOWEVER if its Neg ground, the coils + receives ign switch voltage while its - wires to ground via distributor terminal and eventaully the closed points.

THE REASON FOR ALL THAT IS SO THE PLUG ELECTRONS FLOW FROM THE HOTTER TIP TO THE COOLER GROUND STRAP but if the coil is swapped from the above, electron flow is the wrong way, cool strap to hotter tip.

I see no "EXTRA VOLTAGE" The coil only rises and ramps up high enough so current arc jumps the plug gap BUT NO HIGHER. Its just that if the polarity is correct allowing electron flow from hot tip to cold groudn strap THE VOLTAGE DONT HAVE TO RISE AS HIGH BEFORE THE ARC OCCURS and thats more efficient,,,,,,less work for the coil,,,,,,less wasted heat losses

I guess I may not understand what their argument is all about with talk of "extra voltage" given the physics as I understand it as described above. Bottom line, if the coil polarity correctly matches battery polarity (see my first 2 paragraphs for whats correct) its more efficnet and firing voltage is a few thousand less volts since its much easier to arc the gap if the electrons are flowing the right direction (which correct wiring described above accomplishes)

Thanks again, fun chat, the post above spoke of no way firing voltages were different, I was ONLY trying to educate and explain the engineering and physics of how n why voltages ARE DIFFERENT IF POLARITY CHANGES. Im trying to help NOTTTTT fight

John T

Thank you John T.
I just learned something!

Very interesting, thank you!

Ages ago I taught ag for 3years. Had finished a unit on tune up and general maint. Local farmer said we could use his. Oh. Model h as project. Took boys to farm to load tractor. Farmer stressed it would not start unless pulled. I was talking to farmer. Told boys to go ahead ans check out the h, after only few minutes we heard the h start, boys came up driving it. Farmer asked how did you guys get it started. They stated the coil was wired backward further telling him more energy was needed if backward. I had to pick up buttons which had poped off mt shirt

Thermionic emissions from you are always explanitory. Jim

""Thermionic emissions"" Sounds like something from a medical manual regarding reproduction lol

Are you sure we can say that here??????

Take care Jim,

John T

Best explaination I've seen! Thanks, I knew the resultng facts, but not the nitty-griity on why.

Thanks again,

Areo

Beautiful explaination, John , but I'm thinking there are some who are thinking that if it takes more voltage to jump from cold to hot that that's a good thing? They might get a 8000 volt spark as apposed to a 6000 one. Bottom line is it's still just a spark in my laymans oppinion. If it won't start/run with 6000 it probably won't with 8000 either. You have other problems.

John T,
If I read this correctly: If I had a good way to measure coil output voltage, say a good Oscope, would I see higher voltage peak with the 'wrong' polarity?

Seems so as it is harder to jump the gap, thus voltage should rise to the higher value before decaying as the arc occurs??? right? or wrong?

Meant to add: assuming of course that the coil was capable of building enough voltage to bridge the gap.

Ken, you might see that if you did your experiment with a hot center electrode & a cold side electrode, ,,,however, ....speaking from experience (using a high quality scope) , with both electrodes cold, you just can not discern the difference. The heat/thermionioc emission (or is it nocturnal? ) that make whatever small difference can be found.

Electrons jump from a small sharp point to a broad flat surface. Than they do from a broad flat surface to a point. Cold start advantage due to less voltage required if coil polarity is correct.

The "cranky, middle aged, beer swillin, old geezer" (B&D"s words) must have some custom plugs that he ran through a pencil sharpener. All mine have square edges, one cylindrical & one rectangular in cross section. Frogs jump, electrons flow.
Back to the beer, geezer!