I keep burning up my cylinder 1/4 coil Update

It is a points system

..

Ok, now we're getting somewhere...

In a points/condenser configuration...

All a condenser is is a capacitor, think of it as a mini energy storage device that is charged and discharged.

They do fail thus short to ground thus a source for 1/4 coil excessive current draw. Considering it's only one coil that's being effected here (not both) for a minimal extra $$, change both sets of points/condensers).

OMR

this has been my experience also...dry battery..is a tell tale sign....so ditto on this tip from bounty....



bountyhunter wrote:

Russ Jackson wrote:

It is a points system. I never leave the ignition on. I think the low water in the battery caused it to continue charging at a higher voltage causing the coil to over heat.

A battery losing water is the SYMPTOM, not the cause. The regulator is overcharging it which overheats it and boils the water out and eventually kills it. In that case, the battery is collateral damage and the regulator is the problem.

When points open, coil primary circuit ground is interrupted (which causes high intensity current throughout the secondary loop). The best coil performance is achieved with the most instantaneous interruption of ground.

As the points first begin opening, there's a tendancy toward arcing between the contacts before the gap widens. The condenser momentarily aborbs current to avoid such arcing while the gap has not yet widened.

The arcing has at least two undesirable results:
(1) points pit and burn;
(2) allows more gradual interruption of coil primary circuit ground, which results in weaker spark.

Might be wrong, but thinking shorted or failed condenser (capacitor) won't damage the coil itself, but only reduces the coil's performance.

Good Luck!

But as you wrote yourself... "condenser momentarily aborbs current".... If dead shorted to ground longer durations equates to longer current demands through the coil...

If battery/charging system, why only the 1/4 coil?
I'm not getting this theory....

OMR

Patton wrote:

Might be wrong, but thinking shorted or failed condenser (capacitor) won't damage the coil itself, but only reduces the coil's performance.

Actually, I think it could degrade and kill a coil over time. The condenser supplies some current through the coil primary when the points open, effectively slowing the rate that the current through the coil primary goes down after the points open. That controls the amount of voltage arc appearing across the points. But, the points are in series to ground from the coil primary negative terminal so the coil's primary is getting hit with almost the same voltage that arcs across the points. If that condenser is hosed, the primary will get hit with excessive voltage spikes (so will the secondary, except the spark plug will fire and clamp that side's voltage at whatever it takes to jump the plug gap). The bad condenser theory is definitely worth considering.

Russ Jackson wrote:

First I had an EMGO coil and it stopped working. So I went to the local salvage yard and picked up a used one. Worked fine for 1500 miles. Lately I noticed a strange smell...the coil had leaked a hard plastic substance out the end. Must have gotten pretty hot....

Besides heat and vibration, a common coil killer is voltage overload caused by bad spark plugs or plug wires.

Where a spark plug or plug wire is open or has excessive resistance, the secondary loop voltage may increase enough to where it burns through the coil's internal insulation causing a short.

Coil failure evidenced by melted plastic oozing out the end also occurs with Dyna-S ignition as well as oem points/capacitor ignition. Which oozing coil failure can happen while just cruising along. I had been running a Dyna-S ignition with oem coils for several years, and one day while cruising along the oozing coil failure happened out of the blue. Although uncertain, I suspect the coil failure resulted from the oem coil's permanently connected old hard leaking plug wires, or maybe defective plug caps. It wasn't the non-existent capacitor, and it wasn't the Dyna-S. A new Dyna green coil with new Dyna solid core plug wires completely solved the problem.

I somewhat understand about how leavng the ignition switch turned ON for extended periods while the engine isn't running may allow constant battery positive voltage current in the primary windings whereby the coil may overheat to ooze failure. And that wasn't an issue in this case.

But I still am not getting it as to how a bad capacitor might cause the coil to overheat to ooze failure. Not to say it can't happen.

If interpreting OMR correctly, capacitor failure short to ground results in excessive current draw through the coil whereby longer durations equates to longer current demands through the coil.

And bountyhunter thinks a bad capacitor could degrade and kill a coil over time. The condenser supplies some current through the coil primary when the points open, effectively slowing the rate that the current through the coil primary goes down after the points open. That controls the amount of voltage arc appearing across the points. But, the points are in series to ground from the coil primary negative terminal so the coil's primary is getting hit with almost the same voltage that arcs across the points. If that condenser is hosed, the primary will get hit with excessive voltage spikes (so will the secondary, except the spark plug will fire and clamp that side's voltage at whatever it takes to jump the plug gap). The bad condenser theory is definitely worth considering.

I have not previously envisioned current being supplied from the capacitor through the coil primary. And thinking current is supplied from the coil primary to the capacitor (when points are closed), not the other way around.

Also thought the capacitor's purpose was to afford a more instantaneous collaspe of the magnetic field by speeding up rather than effectively slowing the rate that current through the coil primary goes down after the points open.

And don't understand about the coil being hit with any voltage from the points/capacitor, or hit with excessive voltage from a bad capacitor. Thinking the coil receives current from the battery (not from the points/capacitor), and that the coil does the "hitting" through the secondary loop.

Thought the coil would perform (not as well, but without being damaged) with only points and without a capacitor, having slower collapse of the magnetic field with arcing across the points.

My comprehension of this is woefully lacking, but is due to thinking that "input" to coil from points/capacitor is simply continuous interruption and resumption of ground with the fastest signal possible, and not providing any voltage to the coil.

Am anxious to learn more about this, and unlearn any previous misconceptions.

Good Luck!

Oh crap I think I know where I threw you off Patton...
At first I was like I don;t get it.... Then I re-read and went WTF OMR.... :ohmy:

I wrote secondary, meant primary... Sorry about that...

As in this image, if the cap is shorted to ground or for that matter, the point contacts are shorted for longer durations... this would cause the excessive current draw through the coil.

My bad....

With that corrected....

Now, not arguing at all for I love good discussions and debates especially regarding electrical... As I know some of you others do as well so no flame war here... :laugh:

So, how does over voltage due to charging system or Reg failure, drained battery cause only one coil to be damaged? I mean this is the same Voltage being supplied to both coils...

Now I do understand bad plug wires or resistive plugs on coil/pugs 1/4 drawing excessive current on the SECONDARY side... (think I got that right ) but the charging system/battery theory I'm missing something in what is being depicted....

Ok, I'm old and stupid, I'm just not getting it! :laugh:

Well I have ordered new coil, points, condenser, and regulator. I will get it running and give you the voltage readings. As usual you have provided several conclusions. I thank you and I will give the results to this problem....Russ


Also when removing the coil I noticed that oil from a gasket leak was working its way onto that coil which could also add to the problem.

For an extra $14 probably wise to get new plug wires as well....

Ah hell with it... go DYNA EI and be done with it.... :laugh:

Old Man Rock wrote:

...So, how does over voltage due to charging system or Reg failure, drained battery cause only one coil to be damaged? I mean this is the same Voltage being supplied to both coils...

Now I do understand bad plug wires or resistive plugs on coil/pugs 1/4 drawing excessive current on the SECONDARY side... (think I got that right ) but the charging system/battery theory I'm missing something in what is being depicted....

Am thinking we would agree it's unlikely that coil oozing failure could result from a defective regulator and/or weak battery.

My mental block is in trying to comprehend that coil oozing failure might result from a defective capacitor. I understand that arcing across points contacts results in nano-second slower collapse of the magnetic field (and thereby weaker spark), but don't see how such a miniscule increase in grounded primary winding time could overheat the coil.

Dwell is a measure of the duration of time that the primary circuit of the ignition system is closed to energize the primary windings of the coil. To me this means the time during which points are closed whereby coil primary windings are grounded and the coil is being "charged" with current flowing through the primary windings which builds the magnetic field.

The Dyna-S has longer dwell time than a points/capacitor ignition, which Dyna-S affords a longer time during which current continues flowing in the coil primary windings. And longer than the additional nano-second from a bad capacitor in a points system. Yet Dyna-S doesn't cause coil oozing failure due to prolonged charging session in the coil primary winding. So why would a bad capacitor?

Basically that's where my brain is stuck. (Undoubtedly needs cleaning and lubricating :laugh: ).

Good Luck!

Patton wrote:

Russ Jackson wrote:

First I had an EMGO coil and it stopped working. So I went to the local salvage yard and picked up a used one. Worked fine for 1500 miles. Lately I noticed a strange smell...the coil had leaked a hard plastic substance out the end. Must have gotten pretty hot....

Besides heat and vibration, a common coil killer is voltage overload caused by bad spark plugs or plug wires.

Where a spark plug or plug wire is open or has excessive resistance, the secondary loop voltage may increase enough to where it burns through the coil's internal insulation causing a short.

Coil failure evidenced by melted plastic oozing out the end also occurs with Dyna-S ignition as well as oem points/capacitor ignition. Which oozing coil failure can happen while just cruising along. I had been running a Dyna-S ignition with oem coils for several years, and one day while cruising along the oozing coil failure happened out of the blue. Although uncertain, I suspect the coil failure resulted from the oem coil's permanently connected old hard leaking plug wires, or maybe defective plug caps. It wasn't the non-existent capacitor, and it wasn't the Dyna-S. A new Dyna green coil with new Dyna solid core plug wires completely solved the problem.

I somewhat understand about how leavng the ignition switch turned ON for extended periods while the engine isn't running may allow constant battery positive voltage current in the primary windings whereby the coil may overheat to ooze failure. And that wasn't an issue in this case.

But I still am not getting it as to how a bad capacitor might cause the coil to overheat to ooze failure. Not to say it can't happen.

If interpreting OMR correctly, capacitor failure short to ground results in excessive current draw through the coil whereby longer durations equates to longer current demands through the coil.

And bountyhunter thinks a bad capacitor could degrade and kill a coil over time. The condenser supplies some current through the coil primary when the points open, effectively slowing the rate that the current through the coil primary goes down after the points open. That controls the amount of voltage arc appearing across the points. But, the points are in series to ground from the coil primary negative terminal so the coil's primary is getting hit with almost the same voltage that arcs across the points. If that condenser is hosed, the primary will get hit with excessive voltage spikes (so will the secondary, except the spark plug will fire and clamp that side's voltage at whatever it takes to jump the plug gap). The bad condenser theory is definitely worth considering.

I have not previously envisioned current being supplied from the capacitor through the coil primary. And thinking current is supplied from the coil primary to the capacitor (when points are closed), not the other way around.

Also thought the capacitor's purpose was to afford a more instantaneous collaspe of the magnetic field by speeding up rather than effectively slowing the rate that current through the coil primary goes down after the points open.

And don't understand about the coil being hit with any voltage from the points/capacitor, or hit with excessive voltage from a bad capacitor. Thinking the coil receives current from the battery (not from the points/capacitor), and that the coil does the "hitting" through the secondary loop.

Thought the coil would perform (not as well, but without being damaged) with only points and without a capacitor, having slower collapse of the magnetic field with arcing across the points.

My comprehension of this is woefully lacking, but is due to thinking that "input" to coil from points/capacitor is simply continuous interruption and resumption of ground with the fastest signal possible, and not providing any voltage to the coil.

Am anxious to learn more about this, and unlearn any previous misconceptions.

Good Luck!

Current flows into the condenser from the primary each time the points break, so the condesnser supplies a negative current path used by the primary winding. The law of inductance says current can not stop instantly in any inductor, as this would result in infinite voltage. As the points start to open, the voltage across the cap is zero since closed points short that node to ground. As the points open, the coil current is decreasing rapidly which forces the voltage across the points to rise rapidly. As th voltage across the cap is rapidly increased, current flows into it (it charges up to a higher voltage). In effect, the condenser forms an alternate current flow path for the coil primary allowing the current to flow a little at point break, which slows the fall time of the coil primary current. The fall rate of that primary current is linearly proportional to the voltage generated across the coil primary winding. With no cap or a bad cap across the points, that voltage will be way too high and can break down the primary winding over time.