Topic: Can't find non-resistor plug caps--how do you run DR8EIX iridium resistor plugs?

[Syscrush]

Not many places to park in the sky.

[WarwickE36]

Kinda why I'm on this forum.  Helping people make their bike work well, I feel, is better than telling them to take it to a "professional"

I have heard you tell more than one person to take it to a professional

You like points and thats great, others word rather spend a little extra and not fuss with them and thats great too.  I dont think most of the people here are arguing that points are inferior.  The argument that was placed forth by Spanner was that electronic ignitions are inferior, in which I disagree.  But this dead horse has been beaten it now looks like a mexican donkey after a 10 hour donkey show (urban dictionary.)  Let the great debate rage on. Hate hate hate hate. roble roble roble.

[Holden]

TwoTired and Fasturd have expressed the notion that points work well, but they require periodic maintenance.  I think it's valid to suggest that money spent on something that is presently working well is wasteful.  I respect TwoTired's breadth of electrical knowledge, although I see how some can be offended by his delivery.  As for me, my bike is running well with points right now, but I will buy a PAMCO when they require replacement or I have too much trouble getting them adjusted.  There was no points cover gasket on my bike when I got it, but fortunately the points plate looks pristine.  I've since picked up the gasket.

My understanding is that they have magnetos in planes because they don't require batteries to run (fewer parts to fail), but I could be wrong.  And the expensive certification process with the FAA keeps technology old.  I'm not being critical of the certification process, as it is one of the reasons that public and private air travel is safer than driving.

[mlinder]

I'm not confirming or denying anything with the following question, I'd just like to know:

How does a stock coil discharge at a different rate with elec ign vs points?

Ign triggers discharge. Charge goes from coil down plug wire to plug.

[TwoTired]

They are so reliable they had to install 2 mags per engine incase one fails.

More than just reliability.  Two spark plugs per cylinder also in creases the horsepower output of the engine, since the spark plugs are located on opposite sides of the same combustion chamber.

If you know anything about airplanes, you know they use redundancy on all critical systems.  Often more than just one level.
Have you noticed they put multiple engines on some of them?  Some have a pilot AND a copilot.

Would you want only electronic ignition during a lightning strike?

[TwoTired]

To be clear your only real issue with electronic ignition is the additional cost?  If it were a 50 dollar kit, would you feel differently?

Probably.  If it was still built with proper engineering and had the requisite reliability.  Part of the reason for the current high prices of conversion is low demand and very small production runs. You could get the consumer cost down to about $25 -$35 if you had a production run of a million or so.  I don't believe there are a million buyers, though.  The current electronic offerings (for the SOHC4) are driven by pure profit at the sellers end.

But, I feel what you are really asking is this.  Is it better the give $100 to "charity" or $50.  Does one make you feel twice as good as the other?  Bear in mind you still get to drive your bike without ANY charitable donation. 

Cheers,

[Syscrush]

I'm not confirming or denying anything with the following question, I'd just like to know:

How does a stock coil discharge at a different rate with elec ign vs points?

Ign triggers discharge. Charge goes from coil down plug wire to plug.

During the dwell period, the current flowing through the primary winding creates a magnetic field around the coil.  It takes time to do this because the growing magnetic field cutting through the windings induces a back-EMF (EMF = electromotive force aka voltage) which resists the flow of current.  Think of that growing magnetic field like a balloon that's inflating.

When the circuit energizing the primary coil is cut/opened, that magnetic field collapses, and in collapsing it passes through the secondary windings.  That changing magnetic field passing through the secondary windings induces an EMF that flows a current through the plug wire, across the plug gap, to ground as you describe.

Being a mechanical switch operated by a cam, the points will actually open the circuit less abruptly than a fast transistor can.  The points have some kind of complex interaction with one another (including some arcing visible through a sexy clear points cover) that keeps current flowing in the primary winding during part of the opening phase.

By opening the circuit more abruptly, the magnetic field around the coil will collapse faster.  Faster relative motion between the magnetic field and the coil means a larger induced EMF (same as how generators have higher output when you spin them faster).

Think of it as popping the balloon (electronic) vs just letting go of the opening (points).  The same amount of energy is released in both cases, but the short, sharp release is more powerful, since power = (work or energy)/time.

Does that make sense?

[TwoTired]

Kinda why I'm on this forum.  Helping people make their bike work well, I feel, is better than telling them to take it to a "professional"

I have heard you tell more than one person to take it to a professional

Yes, I have...when it became clear the person had neither the desire, inclination, skills, or desire to gain the skill, necessary to fix their bike.

[mlinder]

I'm not confirming or denying anything with the following question, I'd just like to know:

How does a stock coil discharge at a different rate with elec ign vs points?

Ign triggers discharge. Charge goes from coil down plug wire to plug.

During the dwell period, the current flowing through the primary winding creates a magnetic field around the coil.  It takes time to do this because the growing magnetic field cutting through the windings induces a back-EMF (EMF = electromotive force aka voltage) which resists the flow of current.  Think of that growing magnetic field like a balloon that's inflating.

When the circuit energizing the primary coil is cut/opened, that magnetic field collapses, and in collapsing it passes through the secondary windings.  That changing magnetic field passing through the secondary windings induces an EMF that flows a current through the plug wire, across the plug gap, to ground as you describe.

Being a mechanical switch operated by a cam, the points will actually open the circuit less abruptly than a fast transistor can.  The points have some kind of complex interaction with one another (including some arcing visible through a sexy clear points cover) that keeps current flowing in the primary winding during part of the opening phase.

By opening the circuit more abruptly, the magnetic field around the coil will collapse faster.  Faster relative motion between the magnetic field and the coil means a larger induced EMF (same as how generators have higher output when you spin them faster).

Think of it as popping the balloon (electronic) vs just letting go of the opening (points).  The same amount of energy is released in both cases, but the short, sharp release is more powerful, since power = (work or energy)/time.

Does that make sense?

It does. I'd like to measure it, though.

[Spanner 1]

While the field will collapse much faster with electronic, the dwell compared to points would be the same and the same amount of energy ( H.T. ) would be released, right ?  Is the faster 'flash' of energy usable at the plug tho', or does the very design of a plug dictate how 'fast' it can produce the spark across the gap anyway.... just askin' !

[Syscrush]

It does. I'd like to measure it, though.

I think that there's probably some effect of the condensor in shutting off the primary, but I'm no expert.

I hunted around a bit online for a good oscilloscope trace of points vs. CDI on the primary coil voltage, but came up empty.

[mlinder]

I think Mark (Hondaman) DID do some oscilloscope work with points vs. a Dyna S... I'll look for it.

[mlinder]

http://forums.sohc4.net/index.php?topic=29545.msg304549#msg304549

This is the first one, but there is another.

[mlinder]

Hondaman says the stock coils have a 'fixed' discharge time of 1.5ms. Do you think this is affected by the electronic ignitions quicker off-switch? So far, it appears they are not.

[Syscrush]

While the field will collapse much faster with electronic, the dwell compared to points would be the same and the same amount of energy ( H.T. ) would be released, right ?  Is the faster 'flash' of energy usable at the plug tho', or does the very design of a plug dictate how 'fast' it can produce the spark across the gap anyway.... just askin' !

Same energy, less time = more power.  In principle it should mean a hotter spark.  Most of the energy released at the spark plug gap will be wasted almost all the time in a properly-tuned engine.  A stronger spark can give you a bit more leeway with plugs that might otherwise foul and not fire, or with lighting a mixture that's too rich.

[Syscrush]

http://forums.sohc4.net/index.php?topic=29545.msg304549#msg304549

This is the first one, but there is another.

That scope is on the output of the secondary, not the input to the primary.

[mlinder]

http://forums.sohc4.net/index.php?topic=29545.msg304549#msg304549

This is the first one, but there is another.

That scope is on the output of the secondary, not the input to the primary.

But the output is what we care about. The final result of the spark.

Again, if the honda coils have a fixed 1.5ms discharge time, that's what happens. 1.5ms of spark at the plug.

[dave500]

how come i always get the ugly hostess then delta??explain that!!

Somehow I feel this is a joke, but forgive me Dave, being blond, you have to explain. Do not forget: I'm only here to learn English. Hello Goodbye, Ghow are you, I learnuh English, I learnuh eet from a book, e-ven-tu-al-ly.

it was a joke delta,next time i want the spare or backup hostess.

[pamcopete]

The 1000 hrs for an airplane mag with internal points is when the RPM drop at run-up is outside acceptance range.  Best not to run them to total failure, even though there are two of them.  Not many places to park in the sky.  Repairing the mag routinely entails replacing the points while the worn out shaft bearings are replaced and it is good to go for another 1000-ish hours at near full tilt.  My last two mags went at 900 and 950 hrs respectively.  I don't think the mag points have the same current flowing through them that the SOHC4 routinely does.

FYI: Electronic ignition for aircraft is quite rare.  It is hard to beat the mag (and it's points) for reliability and redundancy.  And a lightning strike will still allow the engine to keep running and make power.  Still, some experimental aircraft are using electronic these days.

Cheers,

TwoTired,

You know as well as I do that you did not go 900 hrs on your mags without having them attended to during the annual or 100 hr. inspection. Typical service life for magnetos is 500 to 800 hrs, so if you got 900+ hours out of your mags before they "went" then you are a pilot / owner who lets the cost of operating an airplane influence the safety of operating an airplane. Hopefully, you didn't carry passengers after 800 hrs on the mags.

You also know that the main reason that there are no aftermarket electronic ignition systems for certified GA aircraft is because of the huge difficulty in getting FAA approval. It has nothing to do with your BS about "lightning strikes".

[TwoTired]

TwoTired,

You know as well as I do that you did not go 900 hrs on your mags without having them attended to during the annual or 100 hr. inspection.

 
You mean the timing checked?  Of course, there is no option.  Did they always need adjustment?  No.  But, it is part of the check list.

Typical service life for magnetos is 500 to 800 hrs, so if you got 900+ hours out of your mags before they "went" then you are a pilot / owner who lets the cost of operating an airplane influence the safety of operating an airplane. Hopefully, you didn't carry passengers after 800 hrs on the mags.

 
Well, you simply don't know what you are talking about...again.
They "went" when the RPM drop at run up went out of limits.  And I didn't fly it like that.  They were actually still working.  Likely went out of limits during the last flight. But, the engine never missed a beat.  It was still quite safe to fly, as the limits are a guideline, not an edict of certain death.  In my case, there was just no need to go fly that day, as it was just a practice flight.
There are certainly brands/types of Mags that can conk out sooner.  1000Hrs is usually when the shaft bearings go and it has little to do with when the internal points stop working.  Can they fail sooner.  Yes.  Just like any electronic ignition slapped together in a garage with no quality control effort.

You also know that the main reason that there are no aftermarket electronic ignition systems for certified GA aircraft is because of the huge difficulty in getting FAA approval. It has nothing to do with your BS about "lightning strikes".

Yep, it costs a lot.  And no one has felt it was "worth it" to certify.  And, you need to change your smoking materials if you think ESD isn't going to be part of the certification.

By the way, have you zapped your ignition module to learn where it fails?

And, why haven't you answered mlinder's question about coil discharge time? 

[kmb69]

I love it!

[Pinhead]

The way I understand it, the coil discharge time is effected by the secondary resistance (plug caps, wires, and spark plugs).

So I would guess the 1.2ms of discharge time would be either a) through the factory plug caps (or some other standard resistance) or b) with no in-line resistance. I would lean towards "b" in order to eliminate unnecessary variables...

Or have I been misunderstanding the situation?

[mlinder]

The way I understand it, the coil discharge time is effected by the secondary resistance (plug caps, wires, and spark plugs).

So I would guess the 1.2ms of discharge time would be either a) through the factory plug caps (or some other standard resistance) or b) with no in-line resistance. I would lean towards "b" in order to eliminate unnecessary variables...

Or have I been misunderstanding the situation?

No. Listen.

How does an ignition somehow change the duration of its DISCHARGE when a given coil has a SET discharge time, in the case of honda stock coils, 1.5ms.

The fixed amount of time is 1.5 seconds from (whatever current charge is) to discharged.

How does an electronic ignition change that in relation to a mechanical ignition if the coil is designed to discharge in 1.5 seconds as a fixed value?

I'm not saying it can't, I'm asking how.

[Deltarider]

This thread has taken several hilarious turns.

I think we have found a challenger to oil threads.

I love it!

Wait, you ain't seen nothing yet! Now for a bit of distraction. On my trip through South-East Asia I've seen many motorcycles that had sparkplugcaps that showed light. They had a transparent part and obviously the current in there had to bridge a gap creating a spark that gives this glowing effect (mostly violet). Convenient to check whether there's spark or not. Ofcourse this costs energy and the points inside the cap eventually will erode somewhat. Still I would like to know if it really effects the quality of the spark between the sparkplugs electrodes. My estimation is the loss is minimal.
I'd love to hear your opinions, preferably based on science.
Can I add another question? Over the HTleads there always runs some energy on the outside. Maybe you know these testers (little screwdiver with some sort of a lamp inside) that you can hold against the leads and the lamp inside will glow as a parasite. If you do this, do you take energy away or is that energy on the outside of the HTleads lost anyway? 

[w1sa]

The way I understand it, the coil discharge time is effected by the secondary resistance (plug caps, wires, and spark plugs).

So I would guess the 1.2ms of discharge time would be either a) through the factory plug caps (or some other standard resistance) or b) with no in-line resistance. I would lean towards "b" in order to eliminate unnecessary variables...

Or have I been misunderstanding the situation?

No. Listen.

How does an ignition somehow change the duration of its DISCHARGE when a given coil has a SET discharge time, in the case of honda stock coils, 1.5ms.

The fixed amount of time is 1.5 seconds from (whatever current charge is) to discharged.

How does an electronic ignition change that in relation to a mechanical ignition if the coil is designed to discharge in 1.5 seconds as a fixed value?

I'm not saying it can't, I'm asking how.

.........the way I understand it.........a coil can't really be designed with a set discharge time, unless (to some degree) the ignition is designed around the specific coil performance characteristics.

.........don't electronic ignitions typically switch quicker(and/if not more efficiently)... wouldn't this change/improve the performance of any given coil/ignition combination.