Back On The Road / Onan MSD Ignition Kit Experience

For those who are interested here is a quick Wikipedia posting on "wasted spark" ignitions like we have on our Onans.

https://en.wikipedia.org/wiki/Wasted_spark

I am not sure what Jim is unhappy about but I do to intend to respond any more to this topic since this was an insignificant point in the first place
and does not need any additional discussion from me.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
I am not arguing with you. I don't know where the bull came from. A slip
of the thumb, I guess.
I have worked on dozens of ONAN twins. The camshaft, which turns at
1/2 the crankshaft speed, and has a lobe on the camshaft that opens the
points. When the lobe opens the points, you are correct that BOTH PLUGS
fire simultaneously. One of the cylinders is near TDC on the compression
stroke, the other is TDC exhaust stroke. This is a "wasted spark" ignition.
Jim Hupy
Salem, Or

On Tue, Jul 16, 2019, 9:47 PM Ken Burton via Gmclist <

> For those who are interested here is a quick Wikipedia posting on "wasted
> spark" ignitions like we have on our Onans.
>
> https://en.wikipedia.org/wiki/Wasted_spark
>
> I am not sure what Jim is unhappy about but I do to intend to respond any
> more to this topic since this was an insignificant point in the first place
> and does not need any additional discussion from me.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
If that's the case (now I have to go look at one of mine), how is it that a single magnet on the flywheel, which produces one spark per round, works?
Does it waste two sparks every other rev?
Also, if that's the case, and it sparks every other rev, one cylinder will never fire because it will always see a spark only on the exhaust stroke.
No?

I'll look (I have two in the garage) and report back.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
4 stroke engines only require a spark every other revolution. The waste
spark on the ONAN and Harley's doesn't do much as there is RARELY a
combustible mixture present on TDC exhaust.
But, CRANKSHAFT TRIGGERED IGNITIONS DO FIRE EVERY RPM. The wasted
sparks don't do much there, either.
Jim Hupy

On Wed, Jul 17, 2019, 6:23 AM Johnny Bridges via Gmclist <

> If that's the case (now I have to go look at one of mine), how is it that
> a single magnet on the flywheel, which produces one spark per round, works?
> Does it waste two sparks every other rev?
> Also, if that's the case, and it sparks every other rev, one cylinder will
> never fire because it will always see a spark only on the exhaust stroke.
> No?
>
> I'll look (I have two in the garage) and report back.
>
> --johnny
> --
> Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
> Braselton, Ga.
> I forgive them all, save those who hurt the dogs. They must answer to me
> in hell
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Guys - The points fire the plugs on EVERY REVOLUTION of the crank; . Yes, Jim is of course correct that the cam rotates at 1/2 crank speed but there are two lobes on the cam driving the points plunger so Ken is correct that there are 1800 sparks per minute. I’ve developed three electronic ignition methods for the Onan and I know it intimately.

—Jim

>
> I am not arguing with you. I don't know where the bull came from. A slip
> of the thumb, I guess.
> I have worked on dozens of ONAN twins. The camshaft, which turns at
> 1/2 the crankshaft speed, and has a lobe on the camshaft that opens the
> points. When the lobe opens the points, you are correct that BOTH PLUGS
> fire simultaneously. One of the cylinders is near TDC on the compression
> stroke, the other is TDC exhaust stroke. This is a "wasted spark" ignition.
> Jim Hupy
> Salem, Or
>
> On Tue, Jul 16, 2019, 9:47 PM Ken Burton via Gmclist <

>
>> For those who are interested here is a quick Wikipedia posting on "wasted
>> spark" ignitions like we have on our Onans.
>>
>> https://en.wikipedia.org/wiki/Wasted_spark
>>
>> I am not sure what Jim is unhappy about but I do to intend to respond any
>> more to this topic since this was an insignificant point in the first place
>> and does not need any additional discussion from me.
>> --
>> Ken Burton - N9KB
>> 76 Palm Beach
>> Hebron, Indiana
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
And we don’t care

On Wed, Jul 17, 2019 at 6:48 AM Jim Miller via Gmclist <

> Guys - The points fire the plugs on EVERY REVOLUTION of the crank; . Yes,
> Jim is of course correct that the cam rotates at 1/2 crank speed but there
> are two lobes on the cam driving the points plunger so Ken is correct that
> there are 1800 sparks per minute. I’ve developed three electronic ignition
> methods for the Onan and I know it intimately.
>
> —Jim
>
> > On Jul 17, 2019, at 1:11 AM, James Hupy via Gmclist <

> >
> > I am not arguing with you. I don't know where the bull came from. A slip
> > of the thumb, I guess.
> > I have worked on dozens of ONAN twins. The camshaft, which turns at
> > 1/2 the crankshaft speed, and has a lobe on the camshaft that opens the
> > points. When the lobe opens the points, you are correct that BOTH PLUGS
> > fire simultaneously. One of the cylinders is near TDC on the compression
> > stroke, the other is TDC exhaust stroke. This is a "wasted spark"
> ignition.
> > Jim Hupy
> > Salem, Or
> >
> > On Tue, Jul 16, 2019, 9:47 PM Ken Burton via Gmclist <

> >
> >> For those who are interested here is a quick Wikipedia posting on
> "wasted
> >> spark" ignitions like we have on our Onans.
> >>
> >> https://en.wikipedia.org/wiki/Wasted_spark
> >>
> >> I am not sure what Jim is unhappy about but I do to intend to respond
> any
> >> more to this topic since this was an insignificant point in the first
> place
> >> and does not need any additional discussion from me.
> >> --
> >> Ken Burton - N9KB
> >> 76 Palm Beach
> >> Hebron, Indiana
> >>
> >> _______________________________________________
> >> GMCnet mailing list
> >> Unsubscribe or Change List Options:
> >> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >>
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://bdub.net/gmcmotorhome.info/
Alternator Protection Cable
http://bdub.net/gmcmotorhome.info/APC.html
 
Well I certainly find it informative and interesting information about the modified Onans waisted spark system. Especially about stronger and
multiple sparking systems firing on the exhaust stroke which helps burn unburned gases which go into the atmosphere. I feel more comfortable sleeping
over a gas burning engine that has lower emissions and less exhaust smell. Crane makes an electronic kit to make Harley's a single fire system using
2 coils but I believe it still starts and idles on dual fire, probably to aid exhaust emissions tests?

> And we don't care
>
>
>
>
>
>
> On Wed, Jul 17, 2019 at 6:48 AM Jim Miller via Gmclist <

>
> > Guys - The points fire the plugs on EVERY REVOLUTION of the crank; . Yes,
> > Jim is of course correct that the cam rotates at 1/2 crank speed but there
> > are two lobes on the cam driving the points plunger so Ken is correct that
> > there are 1800 sparks per minute. I've developed three electronic ignition
> > methods for the Onan and I know it intimately.
> >
> > --Jim
> >

> >>
> >> I am not arguing with you. I don't know where the bull came from. A slip
> >> of the thumb, I guess.
> >> I have worked on dozens of ONAN twins. The camshaft, which turns at
> >> 1/2 the crankshaft speed, and has a lobe on the camshaft that opens the
> >> points. When the lobe opens the points, you are correct that BOTH PLUGS
> >> fire simultaneously. One of the cylinders is near TDC on the compression
> >> stroke, the other is TDC exhaust stroke. This is a "wasted spark"
> > ignition.
> >> Jim Hupy
> >> Salem, Or
> >>

> >>
> >>> For those who are interested here is a quick Wikipedia posting on
> > "wasted
> >>> spark" ignitions like we have on our Onans.
> >>>
> >>> https://en.wikipedia.org/wiki/Wasted_spark
> >>>
> >>> I am not sure what Jim is unhappy about but I do to intend to respond
> > any
> >>> more to this topic since this was an insignificant point in the first
> > place
> >>> and does not need any additional discussion from me.
> >>> --
> >>> Ken Burton - N9KB
> >>> 76 Palm Beach
> >>> Hebron, Indiana
> >>>
> >>> _______________________________________________
> >>> GMCnet mailing list
> >>> Unsubscribe or Change List Options:
> >>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >>>
> >> _______________________________________________
> >> GMCnet mailing list
> >> Unsubscribe or Change List Options:
> >> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> >
> >
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> --
> Gene Fisher -- 74-23,77PB/ore/ca
> "Give a man a fish; you have fed him for today --- give him a URL and
> -------
> http://bdub.net/gmcmotorhome.info/
> Alternator Protection Cable
> http://bdub.net/gmcmotorhome.info/APC.html
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

--
C. Boyd
76 Crestmont
East Tennessee
 
https://www.gmcrvparts.com/product-p/gm28-28.044f.57.1.htm

On Wed, Jul 17, 2019 at 8:22 AM Charles Boyd via Gmclist <

> Well I certainly find it informative and interesting information about the
> modified Onans waisted spark system. Especially about stronger and
> multiple sparking systems firing on the exhaust stroke which helps burn
> unburned gases which go into the atmosphere. I feel more comfortable
> sleeping
> over a gas burning engine that has lower emissions and less exhaust
> smell. Crane makes an electronic kit to make Harley's a single fire system
> using
> 2 coils but I believe it still starts and idles on dual fire, probably to
> aid exhaust emissions tests?
>
>
>
>
>
>
>
>

> > And we don't care
> >
> >
> >
> >
> >
> >
> > On Wed, Jul 17, 2019 at 6:48 AM Jim Miller via Gmclist <

> >
> > > Guys - The points fire the plugs on EVERY REVOLUTION of the crank; .
> Yes,
> > > Jim is of course correct that the cam rotates at 1/2 crank speed but
> there
> > > are two lobes on the cam driving the points plunger so Ken is correct
> that
> > > there are 1800 sparks per minute. I've developed three electronic
> ignition
> > > methods for the Onan and I know it intimately.
> > >
> > > --Jim
> > >
> > >> On Jul 17, 2019, at 1:11 AM, James Hupy via Gmclist

> > >>
> > >> I am not arguing with you. I don't know where the bull came from. A
> slip
> > >> of the thumb, I guess.
> > >> I have worked on dozens of ONAN twins. The camshaft, which turns
> at
> > >> 1/2 the crankshaft speed, and has a lobe on the camshaft that opens
> the
> > >> points. When the lobe opens the points, you are correct that BOTH
> PLUGS
> > >> fire simultaneously. One of the cylinders is near TDC on the
> compression
> > >> stroke, the other is TDC exhaust stroke. This is a "wasted spark"
> > > ignition.
> > >> Jim Hupy
> > >> Salem, Or
> > >>
> > >> On Tue, Jul 16, 2019, 9:47 PM Ken Burton via Gmclist >

> > >>
> > >>> For those who are interested here is a quick Wikipedia posting on
> > > "wasted
> > >>> spark" ignitions like we have on our Onans.
> > >>>
> > >>> https://en.wikipedia.org/wiki/Wasted_spark
> > >>>
> > >>> I am not sure what Jim is unhappy about but I do to intend to
> respond
> > > any
> > >>> more to this topic since this was an insignificant point in the
> first
> > > place
> > >>> and does not need any additional discussion from me.
> > >>> --
> > >>> Ken Burton - N9KB
> > >>> 76 Palm Beach
> > >>> Hebron, Indiana
> > >>>
> > >>> _______________________________________________
> > >>> GMCnet mailing list
> > >>> Unsubscribe or Change List Options:
> > >>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > >>>
> > >> _______________________________________________
> > >> GMCnet mailing list
> > >> Unsubscribe or Change List Options:
> > >> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > >
> > >
> > >
> > >
> > > _______________________________________________
> > > GMCnet mailing list
> > > Unsubscribe or Change List Options:
> > > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > >
> > --
> > Gene Fisher -- 74-23,77PB/ore/ca
> > "Give a man a fish; you have fed him for today --- give him a URL and
> > -------
> > http://bdub.net/gmcmotorhome.info/
> > Alternator Protection Cable
> > http://bdub.net/gmcmotorhome.info/APC.html
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
> --
> C. Boyd
> 76 Crestmont
> East Tennessee
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
Both of the ones in my shop open the points once per rev, by direct inspection. Mr. Miller's explanation is why. Thanks.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
I know we have been to GMC MH Rallies where the geneeators were runing and
the smell of Hydrocarbon was so strong, people were complaining.
I have been using the CAT for a year and have never had to make excuses for
smell.
I learned about this from Jim Miller, so I contacted a manufacturer that
does the CAT for the fire departments chain saw as they do not wat to be
overcome by CO and smell.
We have supplied around douzen units and have received very positive
feedback.

> https://www.gmcrvparts.com/product-p/gm28-28.044f.57.1.htm
>
> On Wed, Jul 17, 2019 at 8:22 AM Charles Boyd via Gmclist <

>
>> Well I certainly find it informative and interesting information about
>> the modified Onans waisted spark system. Especially about stronger and
>> multiple sparking systems firing on the exhaust stroke which helps burn
>> unburned gases which go into the atmosphere. I feel more comfortable
>> sleeping
>> over a gas burning engine that has lower emissions and less exhaust
>> smell. Crane makes an electronic kit to make Harley's a single fire system
>> using
>> 2 coils but I believe it still starts and idles on dual fire, probably to
>> aid exhaust emissions tests?
>>
>>
>>
>>
>>
>>
>>
>>

>> > And we don't care
>> >
>> >
>> >
>> >
>> >
>> >
>> > On Wed, Jul 17, 2019 at 6:48 AM Jim Miller via Gmclist <

>> >
>> > > Guys - The points fire the plugs on EVERY REVOLUTION of the crank; .
>> Yes,
>> > > Jim is of course correct that the cam rotates at 1/2 crank speed but
>> there
>> > > are two lobes on the cam driving the points plunger so Ken is
>> correct that
>> > > there are 1800 sparks per minute. I've developed three electronic
>> ignition
>> > > methods for the Onan and I know it intimately.
>> > >
>> > > --Jim
>> > >
>> > >> On Jul 17, 2019, at 1:11 AM, James Hupy via Gmclist

>> > >>
>> > >> I am not arguing with you. I don't know where the bull came from.
>> A slip
>> > >> of the thumb, I guess.
>> > >> I have worked on dozens of ONAN twins. The camshaft, which
>> turns at
>> > >> 1/2 the crankshaft speed, and has a lobe on the camshaft that opens
>> the
>> > >> points. When the lobe opens the points, you are correct that BOTH
>> PLUGS
>> > >> fire simultaneously. One of the cylinders is near TDC on the
>> compression
>> > >> stroke, the other is TDC exhaust stroke. This is a "wasted spark"
>> > > ignition.
>> > >> Jim Hupy
>> > >> Salem, Or
>> > >>
>> > >> On Tue, Jul 16, 2019, 9:47 PM Ken Burton via Gmclist >

>> > >>
>> > >>> For those who are interested here is a quick Wikipedia posting on
>> > > "wasted
>> > >>> spark" ignitions like we have on our Onans.
>> > >>>
>> > >>> https://en.wikipedia.org/wiki/Wasted_spark
>> > >>>
>> > >>> I am not sure what Jim is unhappy about but I do to intend to
>> respond
>> > > any
>> > >>> more to this topic since this was an insignificant point in the
>> first
>> > > place
>> > >>> and does not need any additional discussion from me.
>> > >>> --
>> > >>> Ken Burton - N9KB
>> > >>> 76 Palm Beach
>> > >>> Hebron, Indiana
>> > >>>
>> > >>> _______________________________________________
>> > >>> GMCnet mailing list
>> > >>> Unsubscribe or Change List Options:
>> > >>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>> > >>>
>> > >> _______________________________________________
>> > >> GMCnet mailing list
>> > >> Unsubscribe or Change List Options:
>> > >> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>> > >
>> > >
>> > >
>> > >
>> > > _______________________________________________
>> > > GMCnet mailing list
>> > > Unsubscribe or Change List Options:
>> > > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>> > >
>> > --
>> > Gene Fisher -- 74-23,77PB/ore/ca
>> > "Give a man a fish; you have fed him for today --- give him a URL and
>> > -------
>> > http://bdub.net/gmcmotorhome.info/
>> > Alternator Protection Cable
>> > http://bdub.net/gmcmotorhome.info/APC.html
>> > _______________________________________________
>> > GMCnet mailing list
>> > Unsubscribe or Change List Options:
>> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>>
>> --
>> C. Boyd
>> 76 Crestmont
>> East Tennessee
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk
> http://www.appliedgmc.com
> 1-800-752-7502
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
Poor points mechanism performance and waste spark ignition are separate issues entirely. Waste spark ignition can be simple as in Onan or Harley or
advanced computer controled as in GM LC2 or 3800 series. If your points are sloppy adding CD will make a more powerful sloppy spark. If your points
are working ok they run fine.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
John,
Don't you agree a sloppy strong spark is better than a weak spark?
I know when I put a engine on a smog machine and adjust ignition timing, I
find very little difference until I go over 5 degrees.

On Wed, Jul 17, 2019 at 11:18 AM John R. Lebetski via Gmclist <

> Poor points mechanism performance and waste spark ignition are separate
> issues entirely. Waste spark ignition can be simple as in Onan or Harley or
> advanced computer controled as in GM LC2 or 3800 series. If your points
> are sloppy adding CD will make a more powerful sloppy spark. If your points
> are working ok they run fine.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
> John,
> Don't you agree a sloppy strong spark is better than a weak spark?
> I know when I put a engine on a smog machine and adjust ignition timing, I
> find very little difference until I go over 5 degrees.

That is why I'm asking the question. I don't know.

I guess my take away is that I should get it up and running before I try to switch to either the MSD or the Pertronics. Especially he MSD since the
MSD uses the push rod timing to trigger off of if I am understanding it correctly. I just need to find the time to put things back together and follow
the ignition troubleshooting process to see if I can get it firing with what I have and then go from there. I do think that there would be a value in
getting it to run with less fumes. On the other hand I have a lot of respect for Ken's opinion. He helped me a lot when I first bought the coach and I
had the opportunity to get to know him a bit.

I can say that if I do go with the Pertronics I'll give you a call.

Thanks,

John
--
John Fredrikson
Fayetteville, GA
1978 Eleganza
 
Mr. Fisher uses the Editorial 'we' :)

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
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