Case 41 Magneto current leak - common culprits?

[ChampagneNBeer]

Hi All,

So I have been working on a 53 Case DC tractor I picked up in non-running condition.

I went through the magneto and cleaned it up and am now getting consistent spark but still no starting of the tractor.

During timing the mag to the impulse, I had all the plugs connected and the #1 cylinder plug out and grounded to the tractor so I could see the spark

Well, every time I turned over the impulse by hand I could feel a shock even though the plugs were connected, which makes me these I have a current leak somewhere.

The color of the spark is mostly yellow too, which has me think not all the current is making it to the plug.

Any common culprits I can check for?

There are no cork gaskets on the mag either, but dont think that should matter.

Thanks

 

[wore out]

(quoted from post at 10:01:11 08/06/22) Hi All,

So I have been working on a 53 Case DC tractor I picked up in non-running condition.

I went through the magneto and cleaned it up and am now getting consistent spark but still no starting of the tractor.

During timing the mag to the impulse, I had all the plugs connected and the #1 cylinder plug out and grounded to the tractor so I could see the spark

Well, every time I turned over the impulse by hand I could feel a shock even though the plugs were connected, which makes me these I have a current leak somewhere.

The color of the spark is mostly yellow too, which has me think not all the current is making it to the plug.

Any common culprits I can check for?

There are no cork gaskets on the mag either, but dont think that should matter.

Thanks

You must have been holding the mag while you turned it and the sparkplugs were grounded to the engine?

Did you expect NOT to be shocked?

 

[ChampagneNBeer]

Hi Wore,



I had all the plugs connected to the tractor and one wire/plug
connected to the frame of the tractor.



I also had on heavy leather work gloves when I hand impulsed the
magneto.



I am not worried about getting shocked, what I dont understand is
if the current when hand impulsed was supposed to go through
the rotor cap to the plugs connected to the tractor then why I
would get shocked from holding just the mag case.



If holding the mag case with all the plugs connected shocks me,
then it means with the mag connected to the tractor current is
also being diverted away from the plugs to the tractor frame,
which would, I would think, lead to a weaker spark - no?

 

[wore out]

Electricity needs a return path.

In this case, you were ''IT''.

All will be well in that department once the mag is fastened to/grounded to the engine.

 

[ChampagneNBeer]

Hi Wore,



Yeah, I understand I was the path, but I just would have figured
that with the plugs connected the least resistance would have
been through the plugs vs me with gloves OR rather, with the
plugs in NO current should have gone through the case to me
(makes me wonder if the condenser is faulty.



Reason being, it makes me think current is then not going to the
plugs in sufficient amount and bypassing through the case when
the mag is connected to the tractor - it would also mean when the
tractor is running it is a moving shock machine

 

[John Saeli]

You would have greater spark had you gapped points @ .012 and I explained why in one of your earlier posts. The cap Gasket DOES need to be in place to prevent Rotor binding. Wires need to be copper core, sounds like you have resistor wires. Plugs need to be Non-Resistor. I recommend Auolite 3116 plugs. When the Mag fires, it needs to unload with no resistance.

 

[ChampagneNBeer]

Hi,

I gapped at .015 cuz that is what YT said to do for Dc tractors in an earlier post - I can move them to .012 without issue.

I was wondering about the cables as well - what is on here are Belden Edge Premium 7mm metallic cables.

Can you explain rotor binding and how the gasket between the cap and magneto base resolves this?

Lastly, Is a gasket between the Magneto and tractor necessary - this doesnt have one there either.

Thanks

 

[tractorguy2]

The cap gasket is available. Without the cap gasket the brushes in the cap push too hard against the rotor. Are your brushes in the cap free to move or are they stuck? They are held in the cap with springs. They should move in and out freely.

The gasket between the mag and tractor is not important. My SC doesn't have one. Truth be told the mag will ground better to the tractor without that gasket.

You do have the rotor timed correctly? The rotor gear has two beveled teeth and the drive gear a dot. At one time the dot was painted red. Most no longer have any red paint left.

You need copper core plug wires. If your wires are marked 7MM. Sounds like they are suppression wires for modern ignition systems. They will give you weak spark and hard on the coil.

 

[tractorguy2]

Well, every time I turned over the impulse by hand I could feel a shock even though the plugs were connected, which makes me these I have a current leak somewhere.

What part of the magneto are you touching when this happens?

 

[ChampagneNBeer]

Hi Tractor,

I didnt pay that close attention but I would say case as I also got shocked when I had it on my leg and turned the impulse and could feel the shocks in both my hand holding the case and other times in my leg.

I guess I just would think if this is happening it would mean if the tractor was running it would be current leaking to the tractor non-stop and you would have a weaker spark cuz of it.

The spark to me isnt the best, kinda a white baby spark - not even a strong one.

 

[ChampagneNBeer]

Hi Tractor,

Thanks for the input.

Yup, rotor is timed red dot tooth to in-between the two red paint notches (the mag looks barely used and original - aside from some corrosion I found on the magnets/coil, you would have thought never used).

The graphite brushes move freely without issue and are still sharp edged and square (flat).

I do see graphite drag marks on the rotor and on the metal piece on the rotor even after spinning a few times.

I can order a gasket or make one from cork? Know thickness?

Yeah, I think the plug wires are definitely for a mod or ignition so will have to order some, wonder if the resistance in those cables is strong enough to allow the spark to leak at the points and therefore shocking me/the case.

 

[mEl]

If you really want to check the mag for spark, take the plug and fasten it to the mag body, What John was trying to tell you and you did not seem to grasp is the spark has to have a direct return path back to the magneto which created it, a wire run from the engine block and clamped to the mag body would do it.

Another hint that I have learned through many years building DC engines. The factory timing with the (D) in the timing hole gives you 0 degrees at impulse click and 30 degrees lag angle. When the impulse is up to speed and the impulse no longer operative the spark advances to the full 30 degrees. Many of you may doubt this but my years of experience on a dyno have shown me that DC engines like much more advance than that for max power, my pullers perform best at about 38 degrees, that advance figure is difficult to get with the slots on the mag, that is why my builds use a distributor setup with much more timing latitude available. I build timing pointers for the front pully and use an advance style timing light to do accurate timing.

 

[ChampagneNBeer]

Hi mEI,



If you are saying the magneto needs to be grounded so the spark
can have a return path back to the magneto after leaving the rotor
to the plugs, then yes - I do not understand why.



Can you help me understand why a loop like that is necessary.



I would think the current would follow the path of least resistance
and that with all the plugs connected that pathway should be to
the plugs, not the grounded case.



To me, the only way I am getting shocked holding the mag case
with the plugs connected is because an internal short is occurring
- probably similar to the points spark - OR it is of greater
resistance to try and send the spark to the plugs vs shorting inside
the mag case, which is then sending current to the case.



Either way, having the magneto grounded so current can return to
it after it has gone to the plugs makes no sense to me.

 

[mEl]

Sir, the opposite end of the high tension lead of the coil that goes through the rotor and cap post is grounded to the mag frame, current that goes out the other end of the coil MUST return to the grounded end, you seem not to have a good grasp on how a completed circuit works and do not seem willing to listen to those of us who do, I have tried as has John to explain that when you hold the mag in your hands and click the impulse the spark must go somewhere and without a direct path back to the mag you are going to feel it trying to find that path, you have no option but to listen or struggle along by yourself, Some of us have been paying our dues on this stuff for half a century or more and you seem to be combative when we take pains to help you understand, it can get discouraging! Take an electric light and just plug one of the prongs in and see how much light you get, same exact principle at work, if your mag was hot enough the spark would jump to the mag from the block and probably kill you in the process!! Your last little statement in your post show all you know about complete circuits.

This post was edited by mEl on 08/07/2022 at 10:30 am.

 

[ChampagneNBeer]

Hi mEI,



Why would a magneto spark kill me? That makes no sense!



Also, just because I ask questions doesnt mean I am being
combative - maybe I am trying to understand what you are saying
yet because you have been paying your dues for a half century
you are just a cranky curmudgeon who expects people to take his
keyboard pounding claptrap on blind faith.

 

[mEl]

Sounds to me like you ought to give up your champagne n beer, but maybe it's to late for that, I have been helping people on this forum for many years and am well respected here, I also hold an Extra class Amateur Radio License gained by studying Electronic theory so if you are gonna call names and get nasty you are talking to the wrong guy. Just being a little facetious about the killing thing but every time you put a post up you further prove that you do not have a clue. True, you do not know me from Adam as far as to what I know or do noy know so just keep posting and maybe you will find someone to agree with you. It is rather funny seeing you make a fool out of yourself and I'm not the only one laughing, we have some smart cookies on here.

This post was edited by mEl on 08/07/2022 at 06:17 pm.

 

[ChampagneNBeer]

Hi mEI,



Think what you like about my response but remember it was IN
RESPONSE to your post - maybe reread your own words and think
on that.



I am happy you are helpful here on the forum as that is one of its
functions - but also understand that someone trying to understand
what someone else is saying and asking questions should be
considered normal and natural NOT combative or meaning they
deserve your ridicule and condescension.



There was no reason for you to insult and insinuate anything
against me in your earlier response and your decision yet you
chose to do so, and so I responded in kind.



Anyway, no point continuing this specific conversation with you -
cast not pearls before swine.



Best

 

[mEl]

Saying that you seemed combative was not insulting, just an observation, and you responded and calling me a curmudgeon , that IS name calling, then blamed ME for name calling. Get it right. you are right, there is no sense taking this any further. My friends on here have this sorted out!

Good Luck with your tractor.

 

[ChampagneNBeer]

Agreed, over it, no point explaining everything insulting and
condescending in your post which started this - best to leave it in
the past



Anywho - thank you again for your time and info and yes, I hope to
get the tractor up and running once some parts come in.



Shes a nice clean ole gal and came with a bucket which is really
what I purchased it for - looking forward to getting it back to doing
some work



Best

 

[Brian on Wadmalaw]

Hey man, really sorry to hijack This post but i stumbled on your old post on the ih offset plow. i have the same exact plow my ol man bought 30 years ago and unfortunately he isn't able to remember much. i tried posting a reply to that post but it said to old, not sure where my reply went but its floating around there somewhere???
Anywho, would love to share info, def ih from their construction side but my model number has worn off above the ih logo.
Thanks a bunch,

 

[ChampagneNBeer]

Hi Brian,



Thanks for reaching out.



For sure, shoot me a message (I think there is a private message
option here on YT).



Best

 

[Brian on Wadmalaw]

i looked and tried it want let me, my contact is public.
thanks!

 

[Brian on Wadmalaw]

i looked and tried it want let me, my contact is public.
thanks!

 

[Brian on Wadmalaw]

Hey, i would like to see if you ever found out about the old IH offset disk harrow. You have your private messaging disabled .Mine is enabled as well as my e-mail
thanks, C&B

.

 

[ChampagneNBeer]

Hi Brian,



Tried checking out your profile for an email but didnt see one -
maybe the page takes a while to update?



I havent found any new info on the model of disc, but did find
some parts I need and maybe those can help reference the model?



Best