On 27/02/2018 12:29, default wrote:
> On Mon, 26 Feb 2018 20:59:58 -0800 (PST), Bret Cahill
> <bretcahill@aol.com> wrote:
>
>> I vaguely remember wasted spark and 2 magnetos but it's like out of one of those REM dreams that make you want to get out of bed in the morning.
>
> Early BMW motorcycles used a magneto with two high tension windings,
> and a wasted spark.
>
> Small planes use two magnetos firing two plugs per cylinder through a
> distributor(s).
>>
>> I'm going over everything that I was doing back then but I cannot remember the engine that prompted the OP.
>>
>> The question is always there:  Is there a "normal" or "correct" state of mind?
>>
> Can't help you with the existential ruminations...  Most folks just
> pick a religion and allow themselves to be led by the nose through the
> morass of philosophical cogitation.
>>
>> Bret Cahill
>>
>>
>> "What a feeble thing is human reason.  A thing is either true or false.  Before I was poor and now I am rich.  Changing my lifestyle is OK, but please, leave my judgment alone."
>>
>> -- Tocqueville
>>
>> "The errors of great minds are more fruitful than the truths of little minds."
>>
>> -- Nietzsche
>
> ---
> This email has been checked for viruses by AVG.
> http://www.avg.com
>


Wasted spark coils are as common as muck these days. Ford have been 
using them on Mondeo and Focus models for at least 20 years. The "coil 
pack" has 2 separate primary windings and 4 secondary windings (for 4 
cylinder motors)

I would be surprised if other mass market car makers have not followed 
suit, and I have a feeling that they are even more common on motorcycles.

and  ... technically speaking the Briggs and Stratton single cylinder 
motor on my lawnmower has a wasted spark. The cam for the contact 
breaker is direct on the crankshaft - even though its a 4 stroke motor.

Also, using 2 distributors to fire 2 plugs per cylinder is not confined 
to planes - in the distant past both Alfa Romeo and Aston Martin have 
fitted systems on road cars. Ferrari have also had a crack at it, but I 
am not sure if the vehicles involved could be called road cars.

Long story short  ... if you look in the local scrapyard you should be 
able to find plenty of material to experiment with.


Have fun ...

AT

On Mon, 26 Feb 2018 20:59:58 -0800 (PST), Bret Cahill
<bretcahill@aol.com> wrote:

>I vaguely remember wasted spark and 2 magnetos but it's like out of one of those REM dreams that make you want to get out of bed in the morning.

Early BMW motorcycles used a magneto with two high tension windings,
and a wasted spark.

Small planes use two magnetos firing two plugs per cylinder through a
distributor(s).
>
>I'm going over everything that I was doing back then but I cannot remember the engine that prompted the OP.
>
>The question is always there:  Is there a "normal" or "correct" state of mind?
>
Can't help you with the existential ruminations...  Most folks just
pick a religion and allow themselves to be led by the nose through the
morass of philosophical cogitation.
>
>Bret Cahill
>
>
>"What a feeble thing is human reason.  A thing is either true or false.  Before I was poor and now I am rich.  Changing my lifestyle is OK, but please, leave my judgment alone."
>
>-- Tocqueville
>
>"The errors of great minds are more fruitful than the truths of little minds."
>
>-- Nietzsche

I vaguely remember wasted spark and 2 magnetos but it's like out of one of those REM dreams that make you want to get out of bed in the morning.

I'm going over everything that I was doing back then but I cannot remember the engine that prompted the OP.

The question is always there:  Is there a "normal" or "correct" state of mind?


Bret Cahill


"What a feeble thing is human reason.  A thing is either true or false.  Before I was poor and now I am rich.  Changing my lifestyle is OK, but please, leave my judgment alone."

-- Tocqueville

"The errors of great minds are more fruitful than the truths of little minds."

-- Nietzsche

On Fri, 23 Feb 2018 11:11:57 -0800 (PST),
dsdieboldtheoriginal@gmail.com wrote:

>The problem is the load, the empty cylinder is not the load, the system is also + and - (single platinum plugs with only the anode or cathode coated installed wrong cause crazy issues and created dibble plats) the system also works on standard i=r/o iirc on voltage needed to bridge the biggest resistance will generate voltage when the field collapsed and set amps and volts for proper heat. 
>
>To increase the voltage in the furring cylinder the waste cylinder has to have resistance higher. Then you run two resistance in a series formula. You also need to know the polarity on the leads and electron flow to determine which gets voltage first and if it should be modified for resistance. 
>
>Also ignition coils are a field collapse system  and only supply voltage based on the need of the resistance. So it might say it�s a 80kv coil but if only 12kv is needed then that�s all it supplies. At 7k rpm in Death Valley 50k might be generated.

I'm having trouble understanding what you are doing, but wasted spark
systems do work and have been around a long time.  It sounds like you
want to run one coil to fire two plugs?  That won't work.

You either need two 6 V coils in series or a 12V motorcycle coil which
has two high voltage windings.

The problem is the load, the empty cylinder is not the load, the system is also + and - (single platinum plugs with only the anode or cathode coated installed wrong cause crazy issues and created dibble plats) the system also works on standard i=r/o iirc on voltage needed to bridge the biggest resistance will generate voltage when the field collapsed and set amps and volts for proper heat. 

To increase the voltage in the furring cylinder the waste cylinder has to have resistance higher. Then you run two resistance in a series formula. You also need to know the polarity on the leads and electron flow to determine which gets voltage first and if it should be modified for resistance. 

Also ignition coils are a field collapse system  and only supply voltage based on the need of the resistance. So it might say it’s a 80kv coil but if only 12kv is needed then that’s all it supplies. At 7k rpm in Death Valley 50k might be generated.

"Jim Thompson" <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in 
message news:34fks7le7odmg9b934rvmd0rrgkb4b80c2@4ax.com...
> On Fri, 01 Jun 2012 20:54:45 -0600, m II <C@in.the.hat> wrote:
>
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>>
>>
>>Ian Field wrote:
>>
>>> I assumed that would be obvious to all but the very thickest of
>>> dumbasses.
>>
>>
>>I should have realized this was just another of your many, ill-formed
>>personalities. Feel the pity.
>>
>>mike
>>
>
> Ian Field is a Larkin boot-licker... behavior just as you'd expect.
>
>                                        ...Jim Thompson


JT is a bitter twisted old nut job who's taken to ripping on me any chance 
he gets - just ignore him and hope he goes away. 

On Fri, 01 Jun 2012 20:54:45 -0600, m II <C@in.the.hat> wrote:

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>
>
>Ian Field wrote:
>
>> I assumed that would be obvious to all but the very thickest of
>> dumbasses.
>
>
>I should have realized this was just another of your many, ill-formed
>personalities. Feel the pity.
>
>mike
>

Ian Field is a Larkin boot-licker... behavior just as you'd expect.
		
                                        ...Jim Thompson
-- 
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.

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Ian Field wrote:

> I assumed that would be obvious to all but the very thickest of
> dumbasses.


I should have realized this was just another of your many, ill-formed
personalities. Feel the pity.

mike










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"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message 
news:kr7yr.30447$x11.25507@newsfe21.iad...
> default wrote:
>
>> On Wed, 30 May 2012 16:26:17 -0700 (PDT), Bret Cahill
>> <BretCahill@peoplepc.com> wrote:
>>
>>
>>>I meant "does doubling the voltage in the primary double the voltage
>>>in the secondary?"
>>
>>
>> Not in the standard Kettering, or any system that depends on the
>> collapsing magnetic field to produce the voltage spike.  With more 
>> voltage you could saturate the iron faster so the "dwell"
>> time could be less (translates to a hotter high RPM spark).
>> Eventually you run up against iron saturation as the limiting factor.
>> Higher voltage increases the ampere-turns and magnetic field strength.
>>
>> You are thinking transformers and applying that to induction coils -
>> two different animals.
>>
>> Now something like a CDI where you operate the coil like a pulse
>> transformer would seem to benefit from increased primary voltage.
>>
>>
>>>>the bike would die if the brake light
>>>>filament burned out and you used the brakes.  (one of its many
>>>>endearing idiosyncrasies)
>>
>>
>>>Sounds like a good safety feature got dove tailed in there.
>>
>>
>> As far as letting you know the light is out  - a resounding YES, but
>> it wasn't easy, or safe,  to drive very far that way, particularly in
>> traffic on hills.
>>>>Johnson and Evinrude both use energy transfer magneto systems with
>>>>dual secondary coils. Or my three outboards do (circa 1987 and
>>>>earlier)  If you need a coil like that - try a junked outboard.
>>>
>>>It might not fit physically but would it work electronically?
>>>
>>>I just read where the CDI coil for a Honda 100 outboard was only 9K
>>>ohms between the two spark plug wires.
>>>
>>>The coil I have is 30K ohms between the two spark plug wires.  If
>>>higher resistance => higher voltage in the secondary this would seem
>>>to be closer to what an energy transfer system might require.
>>
>>
>> I don't think you can put too much trust in DC resistance values.  A
>> high secondary resistance might suggest a lot of  turns of very fine
>> wire, and that would probably be a Kettering system coil where
>> inductive collapse is the means of producing high voltage.  If the
>> system is run as a pulse transformer, turns ratio  would seem to count
>> for more - that is a relatively few turns in the primary and lot in
>> the secondary (something all systems have but I'm talking an order of
>> magnitude fewer primary turns, so they might use larger diameter
>> secondary wire with fewer turns)
>>
>> When all is said and done, it is the energy in the spark that
>> initiates ignition, not the voltage.  A high current spark of 4,000
>> volts may outshine a low current 30 KV spark.
>>
>> Did you also measure from the coil secondaries to ground?  My Honda
>> coils have a bare wire that runs from the molded epoxy housing to the
>> core iron and it is painted black along with the iron - secondary is
>> center tapped to ground (at least when bolted to the frame).
>>
>> And Honda calls it "CDI" but it runs from the battery and the modules
>> that do the switching aren't very large - they are ~1" X 1-1/4" X 3/8"
>> and it is obvious that most of the room inside the things are potting
>> epoxy and large diameter wires (relative to the size of the module).
>> It seems way too small to actually step up voltage to charge a cap to
>> fire the coils.
>>
>> Here is a url for a site that may help a little...
>> http://gardentractorpullingtips.com/ignition.htm
>>
>>
>> http://www.cx500.50webs.com/
>> "How to Build a 1980 Honda CX500C CDI Module"
>>
>> with schematic
> Interesting blog here.
>
>   A few years ago, I assisted a person that was restoring an old car.
>
>  I gave him a circuit that involved using a 555 timer with a few other 
> components to current sense and trigger the coil. He was using the 
> standard auto transformer style of collapsing the field. If you monitor
> the current (Dwell Time) in the circuit, you can pretty much dictate the
> level of spark you need. Putting in a PTC also helped to lower the spark
> level when the engine was hot.
>
>   Monitoring the current in the primary side of the coil will allow you to 
> adjust your dwell time and thus when design properly will also give
> you timing control, all in one..
>
> Jamie


At various times I've tried all kinds of circuits for transistor assisted 
contactor - every single one failed due to the lack of "wetting current", 
oxide, tarnish or whtever insulated the points faces before I got as far as 
the end of the road.

The most successful version to date used a high voltage MOSFET (from flyback 
switcher PSU in 19" monitor) used in basically grounded base mode.

The coil lead was removed from the points abd connected to drain, the gate 
was connected to +12V and the source connected to the points. A suitable 
capacitor was found to put directly in parallel with the LT winding and a 
zener was added to clamp the G/S voltage.

With the conventional coil/points arrangement, the points capacitor slows 
the Dv/Dt so the spark quenches sooner as the points part, but the spark 
still lasts long enough to waste significant energy - with the grounded gate 
MOSFET the points voltage never exceeds 12V. Grounded gate is the fastest 
configuration so the coil current is interrupted orders of magnitude faster 
(you do need that capacitor!).

Not sure what the usual practice elsewhere, but on kettering ign honda 
motorcycles, they usually wind the LT coil with wire having a strong PTC. A 
sample coil drew 8A when connected to a 12V battery, but the reading sank 
steadily untill it levelled out at 4A as the coil became warm - where 
motorcycle coils are mounted gets a good airflow once underway, so they're 
well cooled at normal commuting speeds. 

On Fri, 1 Jun 2012 10:19:29 -0700 (PDT), Bret Cahill
<BretCahill@peoplepc.com> wrote:

>> >http://www.cx500.50webs.com/
>> >"How to Build a 1980 Honda CX500C CDI Module"
>>
>> >with schematic
>>
>> After looking at it ... &#4294967295;I'm wondering if they are using the inductive
>> kick of the coil primary to charge the capacitor to a higher than
>> battery voltage.
>
>At least some CDIs step up from 12 V to 400 V in the CDI module.  If
>it's 12 V DC then there's an inverter as well which is why DC CDIs are
>often larger than AC CDIs.
>
>The coil we're using is only slightly small than the original and
>there 30K ohms between the two plug wires.  A CDI coil might be
>significantly smaller and have lower resistance.
>
>Is there any difference between a "pulsar" and a low voltage magneto?
>It might be easier to omit the points and go to CDI.
>
>
>Bret Cahill

I don't know what a pulsar is - some manufacturer's name for
something?

If you read that URL for small engines he shows how to adapt various
car type solid state ignitions with pickup coils to old points type
small engines.  Nothing looks too easy (to me) but that might all
depend on what type engine you have.

Briggs and Stratton did, and probably still do, have a retro-fit for
magneto coils so that the points are solid state.  I haven't messed
with it myself.