Electrical problem on a H

[Janicholson]

Agree. A crisp, blue, snapping spark works in all cases. Jim

 

[Jim Becker]

(
Quoted from Wiki.

That being said, many modern engines use a ''waste spark'' ignition system firing half of the sparkplugs with a negative spark and the other half with a positive spark.

A "waste spark" means that the plug is fired each revolution of the engine rather than every other revolution. The extra spark is at the end of the exhaust stroke and does nothing, thus is wasted. It means nothing one way or the other about polarity of the spark.

By the way, since the H-4 magneto is powered by a rotating magnet, the polarity of the spark alternates between positive and negative. I can't say that I have noticed any difference in engine behavior between the 2 cylinders that get one vs. the two cylinders that get the other.

 

[rustred]

so why have the coils marked then??? just slap the wires on and go. i did the check myself and wrong polarity had a weaker spark.

 

[wore out]

''The extra spark is at the end of the exhaust stroke and does nothing, thus is wasted. It means nothing one way or the other about polarity of the spark.''

Yes, it does, in the realm I was writing about, since ''waste spark'' vehicle ignition systems typically use coils with two secondary terminals, so ''waste spark'' typically goes hand-in-hand with half of the sparklugs being fired with each polarity.

I agree with you on the alternating spark polarity with MOST magnetos, though!

 

[wore out]

''i did the check myself and wrong polarity had a weaker spark.''

Sorry, I gotta call ''B.S.'' on the observation that the spark is VISIBLY ''weaker'' with coil polarity reversed.

 

[rustred]

Ya ok then. I know what I know. U pull a plug out and
watch the spark from each polarity. As I asked why is it
even marked pos. And neg. On the coil ??? Answer that.
John T had an explanation I remember seeing. And u tell
me why the Massey would not start till I corrected the coil
wires. It was plain to see what I saw on the plugs firing.
So????

 

[grandpa Love]

Holy cow!! I know how to wire a tractor and make it run, 6 volt ,12 volt what ever, missing, chewed,burnt, destroyed wiring....... but after reading all this mess I'm confused. I hope the new guy can sort it out better than I can.

 

[John T]

Answer that. John T had an explanation I remember seeing.

This is based on my old brains recollection but NO WARRANTY so dont anyone have a calf lol it may be right it may be wrong TAKE OR LEAVE AS YOU WELL PLEASE

A coil will still produce a spark at EITHER polarity, however speaking energy wise the system operates more efficient if correct. It has to do with (thermionic emission) how it's easier (less energy wasted/expended) to emit electrons from a relatively HOTTER source (plugs electrode hanging out there in the HOTTTTTTTT combustion chamber) to a relatively colder (plugs ground strap and threads into the cooled cylinder head) surface. Thats why in a radio vacuum tube there's a heater under the cathode from which electrons are emitted to the cooler plate.

NOTE she still fires at right or wrong polarity and I wonder if ones eyes might be able to note the difference BUT HEY IF ONE HAS GOOD EYESIGHT who am I to know or question what they see or claim ?????????? Im NOT saying or judging or questioning...

A physicist friend of mine (the late Duane Larson) ran some tests and measured the voltage at which a plug fired when the coil was wired right or wrong HE FOUND THE PLUGS FIRED (current arc jumped the plug gap) AT SEVERAL THOUSAND VOLTS LESS AT THE RIGHT POLARITY versus when wrong in which case coil voltage had to raise higher (coil had to work more and wasted more heat energy) before current arc jumped the plugs gap BUT OF COURSE PLUGS STILL FIRED.

ALSO a Magneto with its North South rotating magnet fires at different polarity each time (subject to type of mag and its operation and gearing) YET PLUGS STILL FIRE

ALSO ITS MY OPINION theres a reason why coil manufacturers bother to label coil leads + and - or Battery and Distributor or whatever.

So until proven otherwise thats my story and Ima stickin to it lol IE Coil polarity matters.........It will still fire if wired backwards...........Its best and more energy efficient IF WIRED CORRECT AS LABELED........How much if any difference in spark energy or what some person claims to see IM NOTTTTT SAYING

John T Again NO warranty if this is true or false, believe anything you like have a different opinion NO PROBLEM but please with all due respect to one another

 

[Janicholson]

To see the polarity, put a graphite pencil point in a 1/4 inch gap between the bare plug terminal and the plug or ground. When a spark crosses the gap, it will be a pretty clean spark to the pencil, and a flair of emitted carbon and a spark to the plug/ground when correct. The internal coil connections also place the primary winding in a different relationship to the point/condenser terminal!

 

[rustred]

thats what i found when i checked the spark at the plugs, yes they fired but it was a weak spark when polarity backwards. i am not saying it wont fire. but the spark was not strong enough to start the tractor.i could see the difference with my own eyes in the plugs sparking. i asked myself why is that spark so weak, so then i looked at the coil and said aah haa. i then connected the coil correctly and she started as soon as i turned the key just right now one turn.them massey's always start like that. so maybe the coil was already weak to not let it start i dont know but i have been pulling it in the antique pulls and it dont miss a beat. and i agree polarity matters or they would not have them wired according to the battery ground. and just because the plugs were firing dont mean the tractor would start with that spark. my findings and i am sticking to it. i went through this rig-a- ma-roll and thats what i found. and thanks john.

 

[rustred]

yes he has it all figured out and tractor is running. its pretty straight forward. i was in my teens when i knew that you had to connect the pos side of the coil to the battery to start the 1967 gmc truck by hot wiring it, then using a screwdriver to jump the starter solenoid from the pos. battery cable to the s terminal on the solenoid. hood opened from the outside also. doors were never locked. things were simple back them.