Why positive ground was used on old cars, trucks and tractors 

Hi Ken. Thank you for watching and commenting. Yes, clean up every connection on the generator. All the way to the block. Then, if your H is old, the generator field is grounded through the cover on the electrical box! Yeah, a bad design from IH. If the generator is not charging, this is very often the problem. On my H, I ran a braided ground wire from the L,H,D,B switch to ground. A vast improvement. My H is 6 Volt Positive ground and its staying that way. It always charges and starts.

Hi EMF. That is such a cool story! I laughed when you got a detention for thinking outside the box. ha ha Oh, those were the days! Now, imagine had you said: And, no carburetor or distributor either. That would have been worth a suspension from school for 3 days. ha ha Just like getting caught smoking in the welding booth. I will admit, when I was young, and in school, I needed that explanation you gave. I always thought the spark plug fired when the breaker points closed. It took me into college before I understood that the spark happens when the points open.

My P71 4.6 liter Crown Victoria Interceptor has a coil for each cylinder. I drove Taxi Cab in Detroit for 7 years. There the toughest, most durable cars on the road today and I'll stand by every word I just said " TOUGHEST "

@@bryanh1944FBH I figured this out indirectly when I was a kid and playing with a big solenoid coil picking up nails and things and using it for an electromagnet. I was curious to the fact that if I disconnected the coil, I would get much bigger sparks than just shorting out the battery intermittently with a short piece of wire. I was puzzled and thinking why does the coil appear to "pull" more power out of the battery than a dead short? Well, I was holding both wires and I discovered what happens when the current flow stops! I got a hell of a shock from holding one lead in the left hand, and the other lead in the right hand and when the field collapsed in the coil, it went right through both arms through my chest and sat me on my ass. And here I was thinking how can playing with a 6 volt battery possibly give me a worse shock than sticking my finger in a light bulb socket... LOL. I wasn't an ignition coil, but the voltage spike was probably around 200 volts, nowhere near an ignition coil, but probably a lot more current, and 200 volts hurts...

Your teacher wasn't such a bright spark.. 🙄😄

a lot of old engines had a buzz coil for each cylinder before the distributor was invented the Ford Model T is an example.Their sparks went every which way.

Hi Marine 72! Thank you for the comment. You are welcome.

I agree no one could explain as done here, and what exactly is the explanation other than saying observations in an authoritative tone? How can saying electricity travels from one pole to another without mentioning electron theory vs hole theory ever, on God's green earth, be considered an explanation? With all due respect, that is.

You probably just missed out on the 6 volt systems.

Yeah I discovered the hard way ,bk 85 ish I bought the old man a high power Alpine system for his truck and decided to surprise him and pull off a midnight install so when he headed out at 3am he be bumpin ,🤣 at 3am the cab still smelled like smoke ,it was a long week

@@tstricklin4808 it was the thought the counted 😂

Yes I smoked a CB radio a time or two before I started putting a 2 amp fuse in both lines.

Hi Murray! Yes, those electrons can pack a punch. ha ha I too have been shocked by ignition coils. Never a nice experience.

Used to work as a mechanic with a fellow who tested plug wires by spraying them with water and running his hands over them. Would have knocked me to the floor!

@@tedrice1026 Hi Ted. Interesting! When I worked in the field, I saw electricians who would tough 110 Volt circuits to see if they were hot, or not. And, they were all seasoned professionals too!

Now that is old school technology. When you grew up how many dinosaurs were roaming the streets? I never considered that in the era when old cars were totally grounded into metal bumpers

@@ben91069 The same amount of dinosaurs as now, only the air and water were cleaner

Bumpers together, and a piece of coat hanger wire. At 3 am, on a back road in Alabama, drizzling rain...who cares if it burns your hand a little...👍👍

@@nickv1008 LOL, been there😏

That was particularly useful when the batteries were on different sides of the car. Join the red and black together, just make sure they don't short to any bodywork. Automatics are still rare this side of the pond, so bump start and push start are still available. I hate to imagine how many times I used all three methods before I got my first reliable car. Driving used to be an adventure!

Hi Martin! Thank you for the very nice comment. I appreciate it greatly. Enjoy your day.

What magic is this?

Ben Franklin started the + current flow myth but he was fooled by ionic plating of metal in a battery. Later we discovered electrons were actually carrying the current. Today electronic techicians in the military and tech schools are taught electron flow and 'left hand rule' in electromagnetic polarity determination. Classical engineering texts still cling to the 'positive current' flow rules and diodes and transistors still have 'arrows' pointing in the direction of 'positive current' flow and they have texts with 'right hand rule' for electromagnetic polarity determination. In fact it doesn't matter as long as you are consistent in using either one or the other in solving circuit problems.

+ to - is conventional current and is taught to engineers. - to + is electron flow and is taught to technicians. It just adds to the fun when the two try to talk to each other.

+(potential voltage) -( ground/meutral) refers to polarity; +(cathode) -(anode) is a different perspective remember/ study your chemistry. You will not have a vivid understanding on the Laws of electricity if you omit the science part of it.

@Kelly Harbeson ...hole flow was always just for math.

Thank you Billy.

EE here as well. I believe that virtually all of us think in terms of conventional current flow as opposed to "real" current. I find it MUCH easier, generally speaking.

I mostly see the need to know this in vacume tube guitar amps.

@@don_cc123 That works well only until you hit a semiconductor... I think in both terms (electrically bilingual, LOL) [or is it ambidextrous???]

Hi Beirne Farm. Thank you. I would love to come to your farm and look at your tractors!

Hi. Thank you for watching. Its been a while now since your comment. I hope you have five tractors by now! ha ha

Thank you for watching and commenting. Thumbs up! You are exactly right. I like the experience you have! And, both you and I understand the difference between "the spark was coming up the spark plug instead of going down". That makes all the difference in the world.

What does it mean to revise pcb ground buss? I assume pcb means printed circuit board, and noisy? Like metal film resistor vs carbon? Or spurious radiation?

Thank you. I appreciate you watching the video.

Thank you. I appreciate the comment!

It actually goes all the way back to the early telegraph networks.

yes

Hi Ben! Thank you. I agree with you. And, keep the old tractor + ground.

@@bryanh1944FBH I will but I want to make it a 12V positive ground so I can used solid state ignition components instead of points and a higher voltage coil for easy starting in cold weather

Send me more info

I vaguely remember reading a few decades ago, that the primary reason for switching to a negative ground at least on automobiles had something to do with car radios becoming more common. I can't remember exactly why or where I read it? Perhaps it was an article in "American Heritage Invention & Technology" magazine? I don't think, that it was an issue concerning interference, but maybe something to do with having a better ground plane for the antenna? I wish; I could remember, but now that you mention it, maybe whatever I read did say, that the risk of getting hit with 90 vdc plate voltage was the issue, and I'm conflating a different article when it comes to a ground plane? At least, I may have been right, that it had mostly to do with the radio. Am I mis-remembering? Of course tractors, when they switched to negative ground, few if any had radios, but I figured, that they changed to be consistent with cars, to avoid confusion.

You are absolutely wrong. The positive spark is connected to the electrode and the ground is made through the block and the threads. The electrons jump to the electrode. The way you are explaining this suggests the body of the car has the opposite ground than the engine.

@@sparky6086 I think you've got a point here.

The original vacuum tube radios have nothing to do with this. The anodes of the tubes are not supplied directly from the 6V or 12V supply voltage. They used +200V which was produced from a vibrator and transformer. That can be designed to operate from positive or negative ground. However it did become an issue with the latest vacuum tube radios shortly after 12V became common. These radio used 12V on the tube anodes directly from the input, so it did have to be plus 12V (negative ground.).

@@danecantwell22 I first thought the same thing, but I researched what he said and it turns out he is correct. Sparkplugs do want to be positive ground. The coils secondary and primary are isolated from each other. The primary is excited by the cars electrical system and the secondary is charged by transformer action. The secondary produce a large voltage across the spark plug gap in the range 5,000 to 20,000 volts, so this high voltage is going to arch to anything close enough to it. It makes little difference if the spark archs to an electrode at 12 volts or one at 0 volts.

Hi! Thank you so much for watching and commenting! Best wishes to you as well!!

Hi Steve. Thank you for watching and commenting. Very interesting comments. An education that has you determining the direction of rotation before electricity is applied is a very thorough education indeed. We just started our 6 Volt H last weekend after sitting all winter. One crank and it was running. Take it a bit easier on that snow pusher! ha ha

Yes, in all my old positive earth vehicles corrosion at the point of earth was a big problem with corrosion spreading out from that point like the plague. Since we have has negative earth systems body corrosion due to electrical flow seems to be a thing of the past. The days of positive earth, dynamoes and voltage control boxes gave rise to nightmares.....and a lot of vehicle fires...never mess around with a voltage control box unless you really know what you're doing.

I am surprised that he didn't destroy his control cables, choke etc. The starter motor would try to earth through these cables. I had that problem some years ago when an earth strap was left off.

Hi Steven and Nancy! You're very welcome!

Hi Jim! You are exactly right!! This is exactly what happens to spark plugs when the polarity is wrong. When I remake this video, I will have to make that point clearer.

@sourand jaded Tesla coils produce AC. The arcs come from whatever is pointiest. If the electrode at the top of the Tesla coil is a round ball, then the arcs (both positive and negative) will come from each edge, corner, point, or blade of grass around.

hole flow is the flow of positive particle in electronics theory when one electron leaves this spot there is a hole that will move to the next created spot of an electron ergo hole flow

@sourand jaded Not a single crt TV set i know has grounded screen. Grounding the screen would require the cathode side of crt to be at said 20 kV negative. That means, the whole circuit must've be isolated from that high voltage, including all potentiometers, antenna input, speaker/headphones output, mains supply and so on. You can get away with that in some small oscilloscope, where the high voltage would be at 1 kV, but definitively not with TV receiver having up 40 kV. And yes, they do zap, but not stronger than static in clothes. And they attracts a lot of dust which you have to clean with a dry cloth, otherwise you risk receiving serious shock.

@@leopoldpoppenberger8692 Just like 'conventional' current, 'hole flow' is just a conceptual aid. Holes are just spots where there could be an electron, but there isn't, in the same way a vacuum is just a place where there could be matter, but there isn't, not even gas. Holes don't actually move. When an electron moves in the lattice a hole 'appears' where the electron came from and the hole the electron moved into 'disappears' but in another way it doesn't, it just isn't empty anymore. It's still a place where an electron can be, but there is.

@sourand jaded But the cathode is NOT several kV in relation to the grounded frame, for reason I mentioned already. The cathode and Wehnelt cylinder are a part of vision amplifier circuit, which has to operate with about 100 V amplitude and frequency ranging from DC do several MHz. There is no way to shift that signal by potential of tens of kV below ground. The anode side doesn't have any signal on it. It's just DC provided by flyback transformer, filtrated by capacitor made of inner and outer layers of coating on glass of CRT, at the funnel part of it. Maybe that coating made you confused but the anode inside the CRT is very much positive in relation do the ground.

Hi S8 Mury. Yes, the body of the distributor MUST make good contact with the engine block or the ignition system will not work! This has happened to me. The aluminum housing of the distributor gets a layer of oxidation on it and good electrical contact is gone. Especially if its only 6 Volt to start with!

Then you should have called up your buddy with HIS 6 volt system, so you could put them in series and give the poor guy a jump. That would have been the EASIEST thing to do.

Reversing the jumper cables first (of course), 6 volts would have started it. I've heard of guys doing this. The starter doesn't care, it's just turns over, it's pretty tolerant. It may not be ideal, as too many amps at a lower voltage than what the alternator is made for could burn it out. But you'd be stepping it up going through the 12v battery anyway. Now time travel back and say, "Can-do, my friend."

@@mikemotorbike4283 I knew this specific vehicle. I had read the service manual for his Chevy truck. Connecting that starter to a 6 volt battery is how you test the solenoid. The solenoid activates but the starter won't turn. At least in that vehicle. I was pretty sure it wasn't going to start on 6 volts, but I suppose there is a chance he had some aftermarket starter that was entirely different

I remember working on a '27 Mack at my first job. I got the job through my buddy who said I would just be changing oil and sweeping floors. Little did I know I'd rebuild about 6 yugos from 10 of em into running cars. Anyways a customer had a 27 Mack truck ,6v positive ground and the boss asked me how I'd hook up jumper cables. I thought for a second and told him red to red black to black. He asks is the running car negative ground ? Yes. I got a gold star. Then he let me fix a bunch of wiring maladies it had.

I think you could could charge their battery so long as you reversed leads.

send me info.

Better yet slather the connections with silicone grease and it will prevent corrosion in the first place, at the cost of attracting some extra dirt.

My 65 MGB was also positive ground. In fact, all English made cars were positive ground. (non synchro 1st gear is normal in them days. It was also termed "Bull-low" as it pulled like a "bull", as it was all torque. Which is why many started off in second gear instead as it was the most useful gear speed wise and you did not STALL IT. You just had to remember that when connecting jumper cables. Connect directly to the battery. Some early Japanese cars were also positive ground. Maybe Datsun(Nissan)? . You must also remember to check the jumper cables as a joke someone swapped the red clamp with the black clamp. Not a "Factory error" as there are thousands of jumper cables produced so that is a MAJOR ERROR. I got a set of jumpers given to me to jump someone's Toyota at college. So I hooked up the Toy and then to my VW without checking to see if the clamps were the correct color as it was a paired unit. "I ASSUMED IT WAS RIGHT". When I hooked up to my battery there was a lot of sparks(more than normal) The Toy would not crank the starter motor. Weird. I took off the jumper cables and then noticed that the black was red at the other end. The red was black at the other end. It is just a plastic colored shield. I swapped them around so the black had black at the other end, same story for red. Tried again with the connection and this time just a tiny spark(normal)...when connecting the cables. The Toy started up. Trouble with cross connecting is the ALTERNATOR WOULD BLOW IMMEDIATELY WITH THE FIRST BIT OF SPARKING ON A CROSS CONNECTION. That is +$200.(30 years ago)as the alternator diodes are fried(instantly) Not my fault. It was the owner of the Toyota that owned the jumper cables so they were at fault. . but I learned from that incident "NEVER TRUST THE ENDS UNTIL YOU MAKE SURE THEY ARE CORRECT." My air cooled VW was O.K. as I had a generator. They do not like to be backwards but they lived. Pretty certain the chick had to ask her dad to fix the alternator with $$ > it happens once, you remember forever. Syncro First gear happened in about 67(or 70) on VW.air cooled beetles. So I assume other manufacturers did so about the same time. I always drive 4 or 5 speed manual transmissions in my own cars. First is for when you are at a DEAD STOP. So it is used to get you rolling, after that, you never use it again until you are at a stop. or on a really rough bush road going uphill or downhill in the loose gravel or in the snow and let engine speed at idle be the brake.

I doubt it would reverse the wear, but would probably spread it evenly between the center and the tang.

i THINK gm "waste spark" coils also work the same . on my 3.1 (or buick 3.8) it has 3 coils.... 2 terminals on each coil ive also been told that you need double plat spark plugs..... due to the one plug sparking from center to "ground strap".... the other from strap to center . the doub plat plugs have a little "button" on the strap and center.... allowing for good spark control

The cathodic effect.

@@kainhall you need IRIDIUM not platinum, those GM engines with waste spark had pre-detonation issues because of the size of the platinum plus the inefficiency at heat removal(vs copper) iridium is so small tip that it doesnt create piston chipping scenarios and you get 100k service intervals.

I saw a switch on an old Chevy truck back in ‘62. The switch was operated by activating the starter with the foot pedal and it reversed the ignition polarity to minimize metal buildup on the points. Truck was probably a ‘36 or ‘37. Mechanic told me I probably would never see one again.

Hi! Yeah, this happens. My friend "accidently" got his boat battery slightly reverse charged. A modern "smart" charger would not charge the battery. We hooked up a load to the battery and completely drained it before the smart charger would recharge the battery. An older charger would have also worked.

Hi Rick. I agree! I work on a friend's 1944 Farmall H. It can be seen in some of my other videos. It has the original generator. It's 6 Volt and works as well as the day it was made. But, generators are harder to keep going as they do have brushes. And, as we both know, good grounding on 6 Volt systems is everything! Excellent comment. Thank you.

Ha Ha! Thanks Alan. I agree. Funny comment.

Hi RCF! Thank you.

I'm smiling because you texted "elections" instead of electrons (which probably flow from neg to neg 😅). I'm curious now what you guys think about what Tesla would have thought? (WWTD) ? He might have had all the autos driving around using the atmosphere for power eh?

@@ProjectDreamCatcher I don’t know what your talking about…. 😉😂

Hi Andrew! Sorry for your loss. I wish I could have talked to your father. The PBY is my favorite plane. Thank you for your comment.

But the points are on the 12V side (primary) of the coil, not the HV (secondary) side. The cam that operates the points is on the some shaft that rotates the distributor arm but isn't electrically connected to it.

Wow. I had to look this up. The 20,000V is relative to the positive voltage coming from the battery (ignition switch), not ground. So if you want a reverse spark, you would (as you say) isolate the base of the points from ground and connect it to the positive coming from the ignition switch, but also connect the "+" terminal of the coil to ground. Of course then your spark would only be 19,988V (or maybe it would be 20,012V) but I don't think that would make any difference. You might also have to reverse the polarity of the capacitor. If it is electrolytic, it wouldn't like to be hooked up backwards. (probably burst)

@@GordieGii Spot on! I was personally trying to avoid tackling that explanation... Well put.

NPN=not pointing in neg- PNP=Pointing in pos+ transistor

What exactly is the performance edge since all maths work the same for electron theory or hole theory?

Hi! Thank you for watching. I also bet you will have a good ignition system. Best wishes.

Hi Scott, and speaking of cold weather, here it comes ...... Dang it!

What many people don't understand is that electric motors are rated in watts, and watts is volts X amps, and that when you double amps you SQUARE the resistance. That means a 6 volt 200 amp motor and a 12 volt 100 amp motor will perform exactly the same, BUT the 6 volt motor will be far more sensitive to undersized conductors, dirty terminals, etc. because it is drawing twice the amps.

Thank you for adding the engineering explanation and relationship of voltage and current in a circuit. As an engineer, I just know that relationship and forget not everyone thinks like me.

This is the system on my old P&H (Onan) welder. It is a shit design because if one side gets wet or flooded, slightly fouled, etc, the good side will not fire either.

The spark plugs used in those engines have a special material either platinum or iridium on both electrodes so there is no ground electrode erosion from the reversed plug.

@@MatthewBerginGarage interesting

Hi Matthew! Very interesting. Can you tell me more? I bet the plugs were very expensive! I will have to cover this point if/when I ever redo this video. I think this is a very important comment. Thumbs up to you.

Excellent! I bet you have fun at work. Thank you for watching.

Thank you. I am glad you enjoyed.

my grandfathers 61 Mercury was 12v negative ground

@@noti51 Interesting that Ford chose different polarities between two lines of automobiles.

Hi Jamel! Thank you for commenting. OMG! Do I ever envy you! The PBY is my favorite plane. I have been inside several. But, certainly have never flown in one! That picture is one of my "happy places". Thanks again!!

know the funny thing, if you reversed the polarity of everything and changed the NPN to a PNP, the circuit will work almost the same. I learned it the cool way after I though I could just swap the PNP to a NPN and invert the battery, but I forgot the electrolytic capacitors don't like that, you have to reverse them, thus I made a positive ground circuit. the collest thing was mixing PNP and NPN the wrong way and they exploding

I have a diesel technology text book from college thar says it had something to do with early transistors as well.

@chuck 8094 cmos totem pole is basically almost symmetrical, its beautiful, you get it almost for free, but PNP are a bit bigger than NPN, but not by much. In digital logic you end up needing both anyway.

@chuck 8094 "This is relevant in guitar amplifiers because of the coveted vacuum tube sound. " I used to think that the difference was because of the cutoff of saturation of a valve vs the transistor. But that can be simulated perfectly in a circuit by the gain curves and so. But I think to the human ear, what matters most is the kind of "white-noise" produced by the grid of the tube, transistors have none of that, ironically the problem is that they don't have much noise. The human ear really likes the warm sound of the noise floor, its not exactly white-noise, but its noise, and it matters a lot for the feeling. I'm an amateur guitarist.

There is one thing I have observed regarding this topic. This case I am referring too is points ignition system, If the coil is hooked up reverse ie coil + to points (B- switched) and coil - to ign (B+ constant) the spark is weak. If connected coil + to ign (B+) and coil - is connected to points (B- Switched) The spark is strong. I can't think of the reason it would matter unless the condenser/Capacitor is polarity sensitive. As for spark plugs the don't care about polarity as can be seen by your example aka the coils where the secondary is isolated from the primary coil and the secondary coil has both ends of it connected it a spark plug meaning every time the coil is fired one plug sees around -15kv and the other sees around +15kv though the voltages won't be 50/50 as the cylinder with the air fuel charge requires a higher voltage while the cylinder just finishing it's exhaust stroke has ionized gas and lower pressure which conducts electricity better.

Hi ramish! Thank you for your story and watching my video.

Hi. Thank you for the comment. I hope the tractors are still going!

@@bryanh1944FBH he still uses them @76 years old!!!!

Well, sorta, the source implies it connects to a supply rail. What you describe is correct for N channel devices but for P channel it is backwards and source connects to +. That said, there is still a big advantage due to physics of using the N type devices (NPN, N-mosfet, etc) because they have better properties for a given cost than the P type devices. There are even cases where an N type device will be used at the positive side of a circuit even though it requires additional drive circuitry to operate that way, just because the actual switching component can be cheaper.

@@big0bad0brad Correct. Even inside logic chips the designers try to avoid P-channel devices.

Thanks, you too Jorge.

Hi David. Thank you for the comment. I too am learning from all the comments. In time, I would like to do this over and add even more.

Hi Joe! Thumbs up to you and an excellent comment. You are a wealth of knowledge. I wish you were standing in my shop and we were having a long discussion. I would learn a lot from you!! That's for sure.

Hi greenmirror555. Thank you for commenting. One of my favorite tools is a spark tester which allows the spark to be seen (which sounds like you have). As strange as this may sound, I would focus on making sure there is a good ground between the distributor body and cast iron ground (I am assuming this tractor has a distributor and not a magneto). I have seen this problem on tractors that have been sitting. Naturally, this is assuming there is power at the distributor (something as simple as a bad on/off switch). Good luck!!

Hi Delmar. Thanks for sharing. Do you remember, was your new regulator for positive ground? Or, didn't it really say? Just curious .....

@@bryanh1944FBH it was positive ground I think the one I got would work both was once the generator was polarized

Absolutely!

Great reason, except you got it the wrong way round. Look up "sacrificial anode" (positive). With positive earth the whole body becomes the sacrificial anode and that's why it corrodes away. That's the true reason why they changed to negative earth.

Ground polarity has no effect on corrosion in vehicles since all vehicles are isolated from earth ground by rubber tires. However in underground pipes which are 'earth grounded' quite well due to being buried. Anticorrosive voltage/current is applied to underground piping systems to minimize electrochemical corrosion.

@@WJV9 You really are confused. Ground on vehicles is absolutely nothing to do with the physical earth. Don't get confused with earthing of mains electrical installations such as houses. The ground of vehicles is absolutely nothing to do with earthing, and it wouldn't make any difference if there were no rubber tires. The ground on a vehicle, is the use of the metal body work as a common connection point, an easy way to connect things together. So instead of running multiple wires back from rear lights including tail light, flashers, the brake light, the headlights, the horn, the electric window heaters, the electric window winders, they can all connect to the metal body work of the car and it eliminates a large amount of wiring. There is no connection to "ground", or "earth". Not that any is even required.

@@WJV9 -- Well, believe it or not, tyres have enough "carbon black" to be slight conductors.

Hi! Thank you for watching and commenting! Yes, I am a Farmall Fan. I have a beautiful 1944 H (Positive ground and 6 Volt). My favorite tool is a spark tester. It hooks up at the spark plug and you can physically see the spark jump the gap. These are inexpensive tools. Over the many years, I have fixed a lot of stuff with this simple tool and my Volt / Ohm meter. Good luck!! Oh, BYW: I have seen many problems with the On / Off switch not working. One of many things to test.

Wouldn't a positive chassis just mean we consider positive to be the common and negative to be the supply?

@@jeffreystroman2811 yes

Hi Dale! Yes, 6 Volt is fine with the proper gauge wire. Plus, good clean connections. Thank you for your comment.

Hi Colin CK! Interesting point. Thank you.

You remember that he said he was reading his theory. I'd say most of his conclusions are right, but not necessarily how he reached them. That's OK, that's how science works. You come up with a hypothesis, you test it, and if the hypothesis and your observations match then you have a theory. How you came up with the hypothesis doesn't matter, as long as it accurately predicts what will happen, it is a workable theory. When you detect a flaw (like the direction the metal moves in electroplating) then you update your hypothesis and test again. Science isn't an answer, it's a process. (They call it the scientific method.) And while it's a good idea to 'follow the science' it's more important to question the science. Classical physics is really good at predicting how things work, and we still use it all the time, but without quantum physics nobody would have predicted transistors, and if they hadn't predicted them they wouldn't even have tried to figure out how to make them. Transistors were discovered by mathematicians, then physicists could invent them.

@@GordieGii Excellent comment 👌 Some of the so called experts in today's society who are repeating the ' follow the science ' frase ( but are actually advocating that the science is settled) should have a listen. Science is never settled unless one makes the mistake to elevate oneself to God like infallibility, which is one of the ingredients of the downfall of our society.

Hi Okie Tom! Thank you for the comment. I am glad you enjoyed it.

Hi Peter. Thank you! I appreciate that greatly. I grew up south of Regina, Saskatchewan (in ND, USA). To this day, I have a lot of friends from Canada. I am wishing you a good day as well.

@@bryanh1944FBH i am from a farm , 8 miles west of Battleford Sask. Take care of all, in your power.....

Born and raised Calgarian here.

Same

Hi Michael, thank you for commenting. That is very interesting indeed! I've heard a similar theory on Mack trucks and body corrosion.

@@bryanh1944FBH Body corrosion vs positive or negative ground is a new one for me!

It is actually corrosion at the accessory terminals rather than body corrosion. With negative ground, the corrosion will be at the battery posts.

Hi Will! I hope you enjoy your old truck for a very long time. Thank you for the comment.

Hi equiluxe 1! Nice comment. I wonder if tractor manufacturers in the 1930s were concerned about rust? What do you think? Thank you.

Many newer cars with coil packs actually fire 2 plugs at the same time sending voltage from one center electrode to ground tang through the engine to its mating plug tang to center electrode and back to the coil completing the circuit.

@@martyk1156 waste spark systems

@@martyk1156 Hi Marty. That's interesting. I need to learn more about that. Thank you for your comment.

Zephyr's were still positive EARTH right up until 1966 / 7 when the Zephyrs / Zodiacs were on their last model, the Mk4..

I put an old Chrysler positive ground 6 volt radio into a 12 volt negative ground Ford. Had to do the same thing but it worked.

65 Ford Cortina GT, pos gr. First car . Had to wrap my head around this theory, worked well . Later I accidentally wired my73 Chevy wagon coil backwards during a tune up & experienced a crank & No start condition. Another mech noticed and advised me of my error., an easy mistake having recently sent my English Ford to the scrapper , wish I still had it. For the MPG. ⛽️

You are welcome

Hi Andrew! You are so welcome!

@@bryanh1944FBH my Father was an Electrical Engineer and could never get me to understand electricity, I became a Civil Engineer.

@@andrewkast4087 Ha ha. I like that comment. Both are good! You did good.

Hi Louis! Thank you for commenting. I think negative grounded vehicles are easier to service by most mechanics because we all are trained in "conventional current" flow which is positive to negative (hence negative ground). But, that's just my theory. I have seen people somewhat nervous to work on positive ground machinery. But, with a meter, it makes no difference. All their training is still good and applies.

Hi! Very interesting! I wonder why they did that? I wonder, were both plugs the same then?

@@bryanh1944FBH Yes. Both plugs were the same and gapped the same. These were opposed cylinder twins, so both pistons reached TDC at the same time, thus, both plugs needed to fire at the same time. By getting the coil to put out ~60kV, each plug had a voltage drop of 30kV. Had the coil been designed to put out 30kV, and the plugs be in parallel, then it would be possible for the motor to run on only one cylinder.

hahahaha I wonder how many never though of that , that is so funny when that happens , the look on there face's hehehe

Someone above* pointed out that starters are series wound, and as such, rotate only one direction regardless of polarity. (I have not checked this out, but I believe he is correct). *I just saw it again, it was the author that said that...

Hi Howard. Thank you. That is very interesting indeed.

Thank you! Finally a theory with some traction. I had commented above, and had doubts about the ignition coil theory as well, as they can be internally constructed for any polarity desired. This makes sense.

Hi Derek! Thank you for the comment and the lesson. Very interesting.

Hi Wisconsin Oliver Nut! My oldest son is now farming in Wisconsin. He is really starting to get attached to his old Oliver tractor. Ha ha They really were good tractors.

@@bryanh1944FBH yes! I grew up around Olivers in the family, so I am partial to them. I suppose this is the story for a lot of farmers/collectors. But those older tractors that don’t have “chips” are really something special when compared to things now.

Hi Charles. Thank you for the comment. I agree. However, many commenters did not. But, I have seen several very good mechanics troubled by positive ground. But whatever the reason, negative ground is the standard now.

That was my thoughts too. I have not yet looked at when radios became common vs when grounds switched from positive to negative... Also, I don't think the coils dictated grounding, since the secondary could be wound to either polarity desired. It is only an issue if it is not installed as it is designed to be hooked up AFAIK... One would have to dig deeper to see if coils were easier to build one way (or just done that way), or if it had anything to do with the choice of grounding... I don't think the real reasons are as clear as they may appear...

The ignition system primary and secondary coils form two independent systems. Just like the transformer at your house that steps down transmission line voltage to your house voltage. The neutral terminals of both the high and low voltage systems at your house are connected together and bonded to ground at your house first disconnecting means, but the energy transfer between the two systems is derived from the magnetic field in the transformer, not a direct electrical connection. Same thing happens in an ignition coil, there is a primary winding that carries battery voltage, on the secondary coil the positive is connected to ground, and the negative output goes to the spark plugs via the plug wires. Because the two are separated by a magnetic field collapsing which generates the spark, the secondary high voltage system in an engine becomes a "separately derived system". Separately derived systems are power sources with no direct electrical connection between any of the circuit conductors and supply conductors. The energy transfer occurs when a magnetic field is created by the primary coil, then the breaker points interrupt that flow of current causing the magnetic field to suddenly collapse. The condenser (or capacitor) quenches the arc that would otherwise form when the breaker points open. The sudden collapse of the field induces a very high voltage pulse in the secondary winding. In modern cars with coil on plug design, the primary battery voltage is switched on and off by the engine control module eliminating the distributor, breaker points, condenser, etc. The primary coil has thicker wire with fewer turns, the secondary coil has very fine wire, and many thousands of turns of wire, creating a low current but very high voltage spark.

Just to confuse you a little more the secondary high voltage from the coil is an alternating current wave.

​@@martyk1156 I think you are referring to pulsating DC. An example of pulsating DC is what's used for a power inverter, that steps up 12VDC from your car battery to 120 VAC to operate battery chargers, power tools, a microwave oven or coffee maker on that long road trip. except in pure sine wave inverters (more expensive) the output in most inverters is more like a square wave. And most devices will work fine, but you can run into issues with some types of motors, and inductive loads in particular electric discharge lamps (florescent, metal halide and sodium vapor)

@@brnmcc01 your theory has one fatal flaw. inside the coil for there to be seperated primary and secondary coils there would need to be 4 terminals - two for each coil. while this is the case in some modern automotive systems the coils of old had one end of the secondary and one end of the primary tied together. thus the difference between a positive ground and a negative ground coil.(which side is the secondary internally connected to?)transformers are isolated primary and secondary coils are not. thus the reason the spark jumps is there is no common connection when the points open the induced voltage is high enough to overcome the insulation in the circuit(plug gap) i disagree that all spark is positive. the old timers will use a pencil test to prove which polarity it is.

@@martyk1156 Yup it's like half of one sine wave cycle.

Hi James. I too have heard of this. Some Ford (I believe) engines used different plugs for the two sides. There are a few comments about this somewhere in the bunch. Do you know if Onan did that too?

Hi Jonathan! Thanks for listening.