CRWLR

I think that if a magneto ignition was suitable for use on an automobile,
then we would still be using them today instead of having devised a means of
getting rid of them 70-some-odd years ago.







"Kevin" <Kevin@el.net> wrote in message
news:3Mdyb.254542$mZ5.1886878@attbi_s54...
> Is a magneto ignition system more reliable than the alternators used on
> cars? Can you use mags on a jeep ?
>

CRWLR

My lawn mower has a magneto and has no battery or alternator. The magneto
replaces the ignition system, not the charging system. It also is a magnetic
device not a points-based device as another poster suggested -- perhaps the
powerful magnet is the basis for the name, magneto. The large magnet
whirling around the pick up is what creates the electrical pulse needed for
the ignition, not opening and closing points.

I have never seen a magneto system that uses any sort of advance. but this
could be acheived relatively easily. All that is needed is to mount the pick
up on a plate that rotates around the crank shaft. Then, all that would be
required is a means of moving this plate a few degrees when it was desired.
Like I said, I have not seen this sort of thing, but it shouldn't be
impossible to acheive. I think the largest problem to solve in the magneto
system is the length of time it takes to build enough charge to give a
powerful spark. I am not positive, but I think part of the reason that
airplanes have two magnetos is that they are on half cycle duty cycle. That
is, they fire alternately so that they get a rest between firings.
Admittedly, that is a SWAG, but I thought I would throw it out anyway.
Airplanes could use two just so that there is a back up system in case the
primary ignitin system fails. A plane, after all, has considerable safety
problems when the motor quits running, all that happens to a car is that it
rolls to the side of the road.

An automobile has space constraints that would prohibit the application of a
magneto, and one would still need the alternator to power the other
electrical systems on board. It makes more sense from a design perspective
to use the charging system to set up the electrical pulse needed to get the
spark, then use a timing system to provide the spark at the correct instant.





"Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
news:20031129225538908-0900@news.newsguy.com...
> On 29 Nov 2003 07:17 PM, c posted the following:
> >
> >
> > "Kevin" <Kevin@el.net> wrote in message
> > news:3Mdyb.254542$mZ5.1886878@attbi_s54...
> >> Is a magneto ignition system more reliable than the alternators used
> >> on cars? Can you use mags on a jeep ?
> >>
> >
> > A magneto doesn't replace an alternator, it replaces the distributor.
> > Even with a magneto ignition, you'll still need your charging system.
> > Magnetos use points. they are not as reliable as an electronic
> > ignition.
>
> From the standpoint of ignition, the magneto does replace the alternator
> and battery, since the mag generates its own power. You will
> undoubtedly still want the alternator and battery to get the thing
> started and to run electrical accessories. As for reliability, the
> magneto doesn't have to be more reliable than the electronic ignition,
> it only has to be more reliable than the battery and its charging system.
> Other than lack of self-generating ability, the electronic ignition is
> better in every way.
>
> > Also, most of them don't have a mechanical advance, and none
> > I know of has a vacuum advance. This means your timing will not be
> > optimized for light load conditions with the vacuum advance. You can
> > use a magneto on anything they make magnetos for.
>
> This is true.
>
> ----------------------------------------------------
> Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> Remove _kills_spammers_ to reply via email.
> Unofficial Bearhawk FAQ website:
> http://www.rawlinsbrothers.org/bhfaq/

CRWLR

My lawn mower has a magneto and has no battery or alternator. The magneto
replaces the ignition system, not the charging system. It also is a magnetic
device not a points-based device as another poster suggested -- perhaps the
powerful magnet is the basis for the name, magneto. The large magnet
whirling around the pick up is what creates the electrical pulse needed for
the ignition, not opening and closing points.

I have never seen a magneto system that uses any sort of advance. but this
could be acheived relatively easily. All that is needed is to mount the pick
up on a plate that rotates around the crank shaft. Then, all that would be
required is a means of moving this plate a few degrees when it was desired.
Like I said, I have not seen this sort of thing, but it shouldn't be
impossible to acheive. I think the largest problem to solve in the magneto
system is the length of time it takes to build enough charge to give a
powerful spark. I am not positive, but I think part of the reason that
airplanes have two magnetos is that they are on half cycle duty cycle. That
is, they fire alternately so that they get a rest between firings.
Admittedly, that is a SWAG, but I thought I would throw it out anyway.
Airplanes could use two just so that there is a back up system in case the
primary ignitin system fails. A plane, after all, has considerable safety
problems when the motor quits running, all that happens to a car is that it
rolls to the side of the road.

An automobile has space constraints that would prohibit the application of a
magneto, and one would still need the alternator to power the other
electrical systems on board. It makes more sense from a design perspective
to use the charging system to set up the electrical pulse needed to get the
spark, then use a timing system to provide the spark at the correct instant.





"Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
news:20031129225538908-0900@news.newsguy.com...
> On 29 Nov 2003 07:17 PM, c posted the following:
> >
> >
> > "Kevin" <Kevin@el.net> wrote in message
> > news:3Mdyb.254542$mZ5.1886878@attbi_s54...
> >> Is a magneto ignition system more reliable than the alternators used
> >> on cars? Can you use mags on a jeep ?
> >>
> >
> > A magneto doesn't replace an alternator, it replaces the distributor.
> > Even with a magneto ignition, you'll still need your charging system.
> > Magnetos use points. they are not as reliable as an electronic
> > ignition.
>
> From the standpoint of ignition, the magneto does replace the alternator
> and battery, since the mag generates its own power. You will
> undoubtedly still want the alternator and battery to get the thing
> started and to run electrical accessories. As for reliability, the
> magneto doesn't have to be more reliable than the electronic ignition,
> it only has to be more reliable than the battery and its charging system.
> Other than lack of self-generating ability, the electronic ignition is
> better in every way.
>
> > Also, most of them don't have a mechanical advance, and none
> > I know of has a vacuum advance. This means your timing will not be
> > optimized for light load conditions with the vacuum advance. You can
> > use a magneto on anything they make magnetos for.
>
> This is true.
>
> ----------------------------------------------------
> Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> Remove _kills_spammers_ to reply via email.
> Unofficial Bearhawk FAQ website:
> http://www.rawlinsbrothers.org/bhfaq/

CRWLR

My lawn mower has a magneto and has no battery or alternator. The magneto
replaces the ignition system, not the charging system. It also is a magnetic
device not a points-based device as another poster suggested -- perhaps the
powerful magnet is the basis for the name, magneto. The large magnet
whirling around the pick up is what creates the electrical pulse needed for
the ignition, not opening and closing points.

I have never seen a magneto system that uses any sort of advance. but this
could be acheived relatively easily. All that is needed is to mount the pick
up on a plate that rotates around the crank shaft. Then, all that would be
required is a means of moving this plate a few degrees when it was desired.
Like I said, I have not seen this sort of thing, but it shouldn't be
impossible to acheive. I think the largest problem to solve in the magneto
system is the length of time it takes to build enough charge to give a
powerful spark. I am not positive, but I think part of the reason that
airplanes have two magnetos is that they are on half cycle duty cycle. That
is, they fire alternately so that they get a rest between firings.
Admittedly, that is a SWAG, but I thought I would throw it out anyway.
Airplanes could use two just so that there is a back up system in case the
primary ignitin system fails. A plane, after all, has considerable safety
problems when the motor quits running, all that happens to a car is that it
rolls to the side of the road.

An automobile has space constraints that would prohibit the application of a
magneto, and one would still need the alternator to power the other
electrical systems on board. It makes more sense from a design perspective
to use the charging system to set up the electrical pulse needed to get the
spark, then use a timing system to provide the spark at the correct instant.





"Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
news:20031129225538908-0900@news.newsguy.com...
> On 29 Nov 2003 07:17 PM, c posted the following:
> >
> >
> > "Kevin" <Kevin@el.net> wrote in message
> > news:3Mdyb.254542$mZ5.1886878@attbi_s54...
> >> Is a magneto ignition system more reliable than the alternators used
> >> on cars? Can you use mags on a jeep ?
> >>
> >
> > A magneto doesn't replace an alternator, it replaces the distributor.
> > Even with a magneto ignition, you'll still need your charging system.
> > Magnetos use points. they are not as reliable as an electronic
> > ignition.
>
> From the standpoint of ignition, the magneto does replace the alternator
> and battery, since the mag generates its own power. You will
> undoubtedly still want the alternator and battery to get the thing
> started and to run electrical accessories. As for reliability, the
> magneto doesn't have to be more reliable than the electronic ignition,
> it only has to be more reliable than the battery and its charging system.
> Other than lack of self-generating ability, the electronic ignition is
> better in every way.
>
> > Also, most of them don't have a mechanical advance, and none
> > I know of has a vacuum advance. This means your timing will not be
> > optimized for light load conditions with the vacuum advance. You can
> > use a magneto on anything they make magnetos for.
>
> This is true.
>
> ----------------------------------------------------
> Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
> Remove _kills_spammers_ to reply via email.
> Unofficial Bearhawk FAQ website:
> http://www.rawlinsbrothers.org/bhfaq/

Lon Stowell

Approximately 12/1/03 13:44, CRWLR uttered for posterity:

> I think that if a magneto ignition was suitable for use on an automobile,
> then we would still be using them today instead of having devised a means of
> getting rid of them 70-some-odd years ago.

Judson magnetos were still popular as a more reliable and
higher performance replacement for the stock ignition in
British sports cars a mere 35-40 years ago. Whether this
is evidence of merit for the magneto or a comment on
British electrics may be a matter of personal opinion.

They were still popular as working better than the first
coupla generations of transistor ignition systems. Then
somebody from the radar engineer folks married a pulse
transformer to a magnetron type supply with solid state
controls and pretty much kept all of the benefits of
the magneto [better high rpm performance due to dI/dT]
and the transistor [better low rpm performance] by using
multiple pulses at low rpm, tailing off the number of
such as rpm rose. Some of these used the standard points, some
used optical pickups, some used the emerging hall effect
sensors.

As soon as good high energy ignition systems from the
manufacturers hit the streets, magnetos pretty much
disappeared, only to be remembered by aging pilots and
old farts.

--
Still a Raiders fan, but no longer sure why.

Lon Stowell

Approximately 12/1/03 13:44, CRWLR uttered for posterity:

> I think that if a magneto ignition was suitable for use on an automobile,
> then we would still be using them today instead of having devised a means of
> getting rid of them 70-some-odd years ago.

Judson magnetos were still popular as a more reliable and
higher performance replacement for the stock ignition in
British sports cars a mere 35-40 years ago. Whether this
is evidence of merit for the magneto or a comment on
British electrics may be a matter of personal opinion.

They were still popular as working better than the first
coupla generations of transistor ignition systems. Then
somebody from the radar engineer folks married a pulse
transformer to a magnetron type supply with solid state
controls and pretty much kept all of the benefits of
the magneto [better high rpm performance due to dI/dT]
and the transistor [better low rpm performance] by using
multiple pulses at low rpm, tailing off the number of
such as rpm rose. Some of these used the standard points, some
used optical pickups, some used the emerging hall effect
sensors.

As soon as good high energy ignition systems from the
manufacturers hit the streets, magnetos pretty much
disappeared, only to be remembered by aging pilots and
old farts.

--
Still a Raiders fan, but no longer sure why.

Lon Stowell

Approximately 12/1/03 13:44, CRWLR uttered for posterity:

> I think that if a magneto ignition was suitable for use on an automobile,
> then we would still be using them today instead of having devised a means of
> getting rid of them 70-some-odd years ago.

Judson magnetos were still popular as a more reliable and
higher performance replacement for the stock ignition in
British sports cars a mere 35-40 years ago. Whether this
is evidence of merit for the magneto or a comment on
British electrics may be a matter of personal opinion.

They were still popular as working better than the first
coupla generations of transistor ignition systems. Then
somebody from the radar engineer folks married a pulse
transformer to a magnetron type supply with solid state
controls and pretty much kept all of the benefits of
the magneto [better high rpm performance due to dI/dT]
and the transistor [better low rpm performance] by using
multiple pulses at low rpm, tailing off the number of
such as rpm rose. Some of these used the standard points, some
used optical pickups, some used the emerging hall effect
sensors.

As soon as good high energy ignition systems from the
manufacturers hit the streets, magnetos pretty much
disappeared, only to be remembered by aging pilots and
old farts.

--
Still a Raiders fan, but no longer sure why.

Paul Calman

I can still buy a BSA motorcycle timing cover made to run carry a mag for
racing, but modern electronics have made that more of a nostalgia piece.
I used to work for the guy who got all of the mags from the Harrah's
Collection auction. The magnets would go bad unless stored in the correct
position, and they all had points. Some had mechanical advances connected to
a lever in the sterring wheel.
We used to zap unsuspecting visitors often.

--
Paul Calman, Hathaway Pines, California

Paul Calman

I can still buy a BSA motorcycle timing cover made to run carry a mag for
racing, but modern electronics have made that more of a nostalgia piece.
I used to work for the guy who got all of the mags from the Harrah's
Collection auction. The magnets would go bad unless stored in the correct
position, and they all had points. Some had mechanical advances connected to
a lever in the sterring wheel.
We used to zap unsuspecting visitors often.

--
Paul Calman, Hathaway Pines, California

Paul Calman

I can still buy a BSA motorcycle timing cover made to run carry a mag for
racing, but modern electronics have made that more of a nostalgia piece.
I used to work for the guy who got all of the mags from the Harrah's
Collection auction. The magnets would go bad unless stored in the correct
position, and they all had points. Some had mechanical advances connected to
a lever in the sterring wheel.
We used to zap unsuspecting visitors often.

--
Paul Calman, Hathaway Pines, California