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Old 07-21-2014, 04:36 PM   #1
Elffors
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Default Single fire mag troubles..

I got this hunt mag with morris single fire leads which works great but looks like shit.
So i have adapted a distributor maglid from a 4cyl fairbanks tractor mag.
One can easily see that should not work which it doesn't do.
But i dont get it.
With the morris single fire stuff and original lid it runs great.

Then i swap to the tracmag lid and install my special rotor it wont start.

So i can rule out coil, condensener, points

But i got great sparks comming out of all four plugs even at cranking speed.
Timing of mag isn't changed at all.
The thing that bugs me is that, sparks can only arrive at plug if rotor is in correct position when points begin to open.
So i can rule out position of rotor too.
In my book it should work but it don't.

Tomorrow i will had a friend over to help me check timing with a timing light to see if my homemade stuff could "delay" spark.

Thats my last thing to check, after that i have no more ideas.
So more ideas are more than welcome
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Old 07-21-2014, 05:24 PM   #2
Tony the torch
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Default Re: Single fire mag troubles..

a magneto is an A/C (alternating current) powered ignition and single fire plug leads have a diode inside them and one is set to allow positive flow and the other is set to allow negative flow.

you may have the polarity of the leads reversed to the firing order... try switching the plug wires to the firing order and see what happens.
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Last edited by Tony the torch; 07-21-2014 at 05:35 PM.
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Old 07-21-2014, 06:03 PM   #3
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Default Re: Single fire mag troubles..

Assuming (no photos) that you are running a dual output coil, the coil is is your problem.

The dual lead mag coil has a floating ground, it is sent out on one tower and must return on the other.

That is why the morris diode leads require one cap outlet to be grounded if using with single plug heads.

When you change to a fairbanks tractor "distributor" type cap/rotor you have no provision for the spark to return "home".

Or if you are "commonizing" the coil outputs then it is completing the path but has no reason to go through your plugs in order to get there.

Make sense?
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Old 07-21-2014, 07:05 PM   #4
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Default Re: Single fire mag troubles..

Just thinking out loud here but, you say you change out rotors, do you change the timing when ya do? Might be as simple as the rotor is advanced or retarded as compared to the other one.
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Old 07-22-2014, 03:18 AM   #5
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Default Re: Single fire mag troubles..

You can't have potential at both ends of a circuit.

How do you know you are getting spark at each plug in time when the plug is in the cylinder?
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Old 07-22-2014, 07:15 AM   #6
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Default Re: Single fire mag troubles..

Quote:
Originally Posted by Tony the torch View Post
a magneto is an A/C (alternating current) powered ignition and single fire plug leads have a diode inside them and one is set to allow positive flow and the other is set to allow negative flow.

you may have the polarity of the leads reversed to the firing order... try switching the plug wires to the firing order and see what happens.
As i said, i got the single fire leads from morris sorted. Those are not my problem as i don't run them anymore

Quote:
Originally Posted by F.St.M. View Post
Assuming (no photos) that you are running a dual output coil, the coil is is your problem.

The dual lead mag coil has a floating ground, it is sent out on one tower and must return on the other.

That is why the morris diode leads require one cap outlet to be grounded if using with single plug heads.

When you change to a fairbanks tractor "distributor" type cap/rotor you have no provision for the spark to return "home".

Or if you are "commonizing" the coil outputs then it is completing the path but has no reason to go through your plugs in order to get there.

Make sense?
Good point.
I didn't really know why but since one cap outlet was grounded in the morris manual that came with the single fire stuff i assumed that i should ground one outlet when i run my trac mag stuff too.
so that's not my problem either.

Quote:
Originally Posted by little d View Post
Just thinking out loud here but, you say you change out rotors, do you change the timing when ya do? Might be as simple as the rotor is advanced or retarded as compared to the other one.
The distributor is bolted to the mag. So timing changes when i turn the mag.
The rotor can only be in the right or in the wrong position. Since i have great blue sparks i assume its in the right.
position of mag isnt changed from when it was running single fire leads from morris.

Quote:
Originally Posted by JAWS View Post
You can't have potential at both ends of a circuit.

How do you know you are getting spark at each plug in time when the plug is in the cylinder?
I don't know why you assume that i am trying to get potential at both ends
I don't know if it sparks when its in the cylinder. maybe that can be check with timing strobe light too.

Thank guy's for taking youre time with me
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Old 07-22-2014, 11:52 AM   #7
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Default Re: Single fire mag troubles..

Ok. Spark is spark. Nice big blue yummy spark. If its at the correct time, inside the chamber. it should and would work.

How do you know for certain it is exactly the same timing? You added another component and it moves. It as circle of influence is larger than the points cam. Even if in the same position, it can seem like it will be later in motion getting there. Meaning there is more time or adjustment. Only takes a few millaseconds and that would be a degree or two off.

I dont know if im making sense. It does in my head.
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Old 07-22-2014, 02:54 PM   #8
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Default Re: Single fire mag troubles..

Jaws....... Let's say the Spark is not a big fat Blue spark... what would
cause a weak orange spark on a mag?
I am having trouble with my morris G5 mag, I get spark, & it jumps a 1/2"
gap if I place 2 paperclips into the top cap, But the color is more orange than
blue. not trying to derail the thread to my problem, but
thought this info regarding the intensity of the spark could be useful for everyone
reading this thread.
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Old 07-22-2014, 03:07 PM   #9
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Question Re: Single fire mag troubles..

Quote:
Originally Posted by F.St.M. View Post
Assuming (no photos) that you are running a dual output coil, the coil is is your problem.

The dual lead mag coil has a floating ground, it is sent out on one tower and must return on the other.

That is why the morris diode leads require one cap outlet to be grounded if using with single plug heads.

When you change to a fairbanks tractor "distributor" type cap/rotor you have no provision for the spark to return "home".

Or if you are "commonizing" the coil outputs then it is completing the path but has no reason to go through your plugs in order to get there.

Make sense?
This comment makes the most sense to me, IF you are running a dual lead mag. Are you?

But then two sets of the single fire wires in the original two post cap would do the same thing, and if it is working that way, is seems like it should work with the four post tracto cap also.

Hmmmmm......
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Old 07-22-2014, 04:14 PM   #10
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Default Re: Single fire mag troubles..

Quote:
Originally Posted by lairdog View Post
Jaws....... Let's say the Spark is not a big fat Blue spark... what would
cause a weak orange spark on a mag?
I am having trouble with my morris G5 mag, I get spark, & it jumps a 1/2"
gap if I place 2 paperclips into the top cap, But the color is more orange than
blue. not trying to derail the thread to my problem, but
thought this info regarding the intensity of the spark could be useful for everyone
reading this thread.
Couple of things, and the order in which Id check....1) points - correct gap (on each lobe) and condition; 2)condensor; 3)coil; 4)quality/condition of the magnets

And lastly, how fast your kickin' and the ambient temperature. Cold day, cold motor and 50wt oil....make for some significant drag on spinning those flywheels

Last edited by buckman50; 07-22-2014 at 04:21 PM.
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Old 07-22-2014, 07:40 PM   #11
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Default Re: Single fire mag troubles..

Quote:
Originally Posted by Elffors View Post
Good point.
I didn't really know why but since one cap outlet was grounded in the morris manual that came with the single fire stuff i assumed that i should ground one outlet when i run my trac mag stuff too.
so that's not my problem either.



The distributor is bolted to the mag. So timing changes when i turn the mag.
The rotor can only be in the right or in the wrong position. Since i have great blue sparks i assume its in the right.
position of mag isnt changed from when it was running single fire leads from morris.
Ok, so one coil tower is earthed, the other tower discharges to the fairbanks rotor setup, jumps a gap to the appropriate cap contact, then follows a wire lead to fire a single plug. The spark then jumps the plug gap to the head/crankcase(earth) then returns to the coil tower via your previously mentioned connection.

Now, your dual fire magneto's magnet rotor then tickles the coil into another discharge not at 90 or 180 degrees later, but rather 157.5 or 202.5 degrees later as the narrow and wide lobes are NOT setup like a British twin but rather for the 45deg vee. "From the time the rear cylinder fires, the engine will rotate 405 degrees (one full revolution plus 45 degrees) and then fire the front cylinder. From that point, the engine will rotate 315 degrees (one full revolution less 45 degrees) and fire the rear cylinder again."

What happens at that point? Is your cap setup like a traditional Fairbanks-Morse tractor mag in which the cap quadrants are 90 degrees symmetrically? How then will the odd degree discharge find its way back?

Have you a photo of your setup that will help me to understand what you have?

I'd love to help you sort this. I tried something similar a few years back unsuccessfully. I could have made it work with a custom ground lobe on my magnet rotor, but went with dual mag heads instead.

Fritz
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Old 07-22-2014, 08:42 PM   #12
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Default Re: Single fire mag troubles..

Handy diagram that makes HD timing events easier to understand for those that find it confusing. . .

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Old 07-23-2014, 01:13 AM   #13
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Default Re: Single fire mag troubles..

Bingo! Fritz put it in better words! Jason nice attachment

Thanks.
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Old 07-23-2014, 04:48 AM   #14
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Default Re: Single fire mag troubles..

Quote:
Originally Posted by 2Loose View Post
This comment makes the most sense to me, IF you are running a dual lead mag. Are you?

But then two sets of the single fire wires in the original two post cap would do the same thing, and if it is working that way, is seems like it should work with the four post tracto cap also.

Hmmmmm......
Yes i am but i have the old single lead fairbanks coil too. which sparks but now i am trying to run this set up as close to the working Hunt mag/ morris single fire cables as possible

Quote:
Originally Posted by buckman50 View Post
Couple of things, and the order in which Id check....1) points - correct gap (on each lobe) and condition; 2)condensor; 3)coil; 4)quality/condition of the magnets

And lastly, how fast your kickin' and the ambient temperature. Cold day, cold motor and 50wt oil....make for some significant drag on spinning those flywheels
I tried kicking with a timing light last night which flashes when a spark goes through the lead. And with the plugs in the heads the light flashes when i kick, soo now i know theres spark under kicking conditions

Quote:
Originally Posted by F.St.M. View Post
Ok, so one coil tower is earthed, the other tower discharges to the fairbanks rotor setup, jumps a gap to the appropriate cap contact, then follows a wire lead to fire a single plug. The spark then jumps the plug gap to the head/crankcase(earth) then returns to the coil tower via your previously mentioned connection.

Now, your dual fire magneto's magnet rotor then tickles the coil into another discharge not at 90 or 180 degrees later, but rather 157.5 or 202.5 degrees later as the narrow and wide lobes are NOT setup like a British twin but rather for the 45deg vee. "From the time the rear cylinder fires, the engine will rotate 405 degrees (one full revolution plus 45 degrees) and then fire the front cylinder. From that point, the engine will rotate 315 degrees (one full revolution less 45 degrees) and fire the rear cylinder again."

What happens at that point? Is your cap setup like a traditional Fairbanks-Morse tractor mag in which the cap quadrants are 90 degrees symmetrically? How then will the odd degree discharge find its way back?

Have you a photo of your setup that will help me to understand what you have?

I'd love to help you sort this. I tried something similar a few years back unsuccessfully. I could have made it work with a custom ground lobe on my magnet rotor, but went with dual mag heads instead.

Fritz
The trick is the rotor. The original rotor has only one lead i have/had 4. they are arranged as an X shape. So when circiut breaker opens small lobe. spark goes out through cap quadrant 1 and 3 then the rotor rotates 157.5 degrees theres new rotor leads to carry the spark out through quadrants 2 and 4 then the first rotor lead are nowhere near any quadrants so it can't carry out any waste sparks

Quote:
Originally Posted by JasonMcElroy View Post
Handy diagram that makes HD timing events easier to understand for those that find it confusing. . .

Good stuff there. I had all that in my head but it is always easier to see on paper. thanks

Quote:
Originally Posted by JAWS View Post
Ok. Spark is spark. Nice big blue yummy spark. If its at the correct time, inside the chamber. it should and would work.

How do you know for certain it is exactly the same timing? You added another component and it moves. It as circle of influence is larger than the points cam. Even if in the same position, it can seem like it will be later in motion getting there. Meaning there is more time or adjustment. Only takes a few millaseconds and that would be a degree or two off.

I dont know if im making sense. It does in my head.
Now i know theres spark under firing conditions. But...

When i kick with the plug laying on the head theres even good sparks on the rear jug. on the front theres Even sparks of a lesser quality

With the plugs in the heads timing light flashes evenly at the rear and a bit irratic at the front. So i have a problem there.

But timing was off. flashing into the timing hole we didn't see anything. Timing light had an advance gadget so we advanced timing 10 degrees and then we saw the tdc mark. i turn the mag until i ran out off adjustability and then we saw the tdc mark at 20 degrees. i wanna see the 30degree timing mark in that hole!

Some how the tracmag affects timing.

My mag is attached so idiotic so i have to take the whole camcover off to turn the mag drivegear a tooth. So that's what i am gonna do tonight.

Thanks all of you guys!
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Old 07-23-2014, 01:04 PM   #15
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Default Re: Single fire mag troubles..

Now we are talking....

Im not crazy. The points are set at the moment they break. Clock starts and by the time the process is over the flywheel has rolled X degrees. The more components, the longer the arc or rotor length all effect timing.

The Hunt fires almost as soon as the points break due to less moving parts or shorter distances or whatever in detail without going into how a coil works blah blah blah.

Tractor mag is a mix of mag and spark distribution.

Fact. Both make spark.
Fact. Spark needs to be at appropriate time to make combustion properly blah blah blah
Fact. Mag in it's current position engine will run
Fact. Tractor mag in the same position will not.
Proves there is a timing issue or difference that needs to be determined.

I bet once the tractor mag is actually timed accordingly, she will run.

This is fun to watch. Keep up the good work.
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Old 07-23-2014, 01:29 PM   #16
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Default Re: Single fire mag troubles..

You're probably right. I wished that we did more tests last night.

we could have tested if a cable bolted to the coil would have a diffrent timing than the tracmag stuff.
And what was the actual timing of the morris stuff?
i need a guy to turn the rear wheel to flash into the timing hole, and my main guy isn't available for a couple of days.

With this internet thing i feel i have at least 15 guy's i could call and they help me in a heart beat but they are at least 10 metric miles away from here. It probably wouldn't be a problem two find a couple of guy's on the other side of the world.
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Old 07-24-2014, 03:12 AM   #17
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Default Re: Single fire mag troubles..

I can think of a few.......
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Old 07-24-2014, 08:29 AM   #18
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Default Re: Single fire mag troubles..

Thank you Jason, right click-save.
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Old 07-25-2014, 09:57 AM   #19
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Default Re: Single fire mag troubles..

Quote:
Originally Posted by little d View Post
Thank you Jason, right click-save.
You're welcome.

I drew that up when making an ignition for a buddy a couple years ago. Needed to "prove" an idea and only seeing it on paper would do.

Article is here (with a permalink to that diagram too):

Early HD Ignition Timer Conversion

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Old 07-27-2014, 02:14 AM   #20
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Default Re: Single fire mag troubles..

Thats just too cool, Jason,
Much Aloha for posting that....
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