Portland fever is definitely in the air! Preparations for travel
to the annual gathering are underway for engine enthusiasts from
Australia, Holland, United Kingdom and of course across the U.S.
For those of us on the Stationary Engine Mailing List, hosted by
ATIS, the Antique Tractor Internet Service, it is a fantastic
chance to meet all the folks we correspond with every day by
e-mail.
It’s a unique opportunity for List members, because instead
of trying to describe problems and solutions with engines, we can
show each other! And maybe, as we all look forward to seeing each
other, that’s why there hasn’t been a lot of indepth
discussion on the List for the past month. The questions raised
have mostly been answered with a single e-mail or two, so there
hasn’t been much for me to pass on to the readers of GEM. –
Helen
In the same way as people around the world tuck items
away in the corners of engine sheds just because they look
interesting and might be useful some day, I hoard old e-mails. The
only query to the List I felt had the basis of a worthwhile subject
was about an EK magneto. While the post in itself didn’t
provide a lot of information, it gave me the idea of searching
through older e-mails in a bid to make up a definitive collection
of magneto tips.
I have an EK magneto on an engine that appears to have been
rebuilt. Everything inside looks new. The problem I have is a very
weak spark – I can hardly feel it or see it with a spark tester. If
I disconnect the wire and condenser from the inside and give it a
few minutes and then reconnect, I get two good sparks and then it
goes back to being weak. I have cleaned the points and tried a new
condenser, but the results are the same. Any suggestions?
I’ve only touched on the subject of magnetos once
before in these articles, and I assure you I have been most careful
to use information only from those whom I consider to be the most
knowledgeable in this area so that I can be confident of passing on
the most reliable information.
The most suspect part of an original EK is the capacitor. They
just don’t last this long. If the magneto looks mechanically
okay, the capacitor is the first part to consider. It’s not
possible to conclude a cap is good by testing it under conditions
different from those in which it operates. Luckily, they’re
cheap enough so you can just put in a new one.
Here’s a little tip that was passed on to me by Bill
Young (an engine collector living in Japan). A weak area of the EK
design is the movable point. It is grounded primarily through the
bore in which it travels. If the bore becomes sloppy through wear,
if dirt accumulates or if you become overly enthusiastic with the
oilcan, resistance will be added to that part of the circuit.
Minimal voltage loss in a magneto that is otherwise marginal can
result in substantial degradation of the spark. The fix is to add a
shunt wire from the point adjustment screw to the body of the
magneto. The next question concerns broken magnets inside the
magneto.
I finally got my upright Maytag running and discovered that the
magnet is broken in half. She still wants to run. Can a guy weld
and recharge those magnetos, or I am better off to find a
replacement?
NO, NO, NO, NO! Don’t weld your magnet! It will be ruined,
and for several reasons.
First, the heat of welding will alter the properties and create
a ‘dead spot’ in your magnet. Second, welding will spread
apart the two halves of your magnet leaving an air gap inside.
Leave your magnet as it is and keep your eyes open for a
replacement (I doubt you will find one). Check the magnets on later
Johnson Utilimotors, they might be the same. FW magnetos for
uprights were made by Quick-Action Magneto Co. At some point, they
switched to Bosch. They look similar; you might get lucky.
Actually, unless the magnet is trying to fall off, it is
probably best to leave it as it is. Two pieces of a broken magnet
will be as good as a whole as long as they are in contact with each
other and the core and are ‘saturated.’
If one or both pieces are in danger of coming off, then it is
best to only tack weld them on each side. Keep in mind that heat is
the greatest killer of magnets. In order for a steel based magnet
to be a magnet it must be very hard. Welding will destroy the
temper in the steel and weaken the magnet. If appearance is your
number-one consideration, then a replacement would be best.
Polarity should always be checked with a compass; do not depend
on any markings, they can be – and many times are -wrong.
Use your compass only for comparison. Compasses that live close
to magneto chargers can and do get reversed. Check your charger
first, then the magnet to make sure they are opposites.
The note about polarity of the magnets is a crucial one,
as is not relying on any markings found on the
magnets.
I can’t even begin to guess how many times people have asked
why the ‘NE’ marking on the magnets isn’t north (or
northeast?). I think it is actually the logo of the magnet maker,
‘Northern Electric.’
Don’t trust the markings, and be sure to check your compass
before charging your magnets. Mine gets repolarized about once a
year if I am not careful. I never use my hiking compass to charge
magnetos. I might get really lost someday!
On another note, chargers will reverse if you change the way
they are connected to the power source. I don’t recommend
marking the poles of a charger, either; check with a compass every
time.
North and south are not really important, opposite is what
counts.
Okay, here’s a question that gnaws at my guts – I’ve
searched the Web, asked around, and nobody has been able to answer
this in black-and-white.
Given: Magnets are marked N and S for the north and south poles.
The compass is marked N and S for the north and south poles. The
map is marked N and S for the north and south poles.
Observation: When I stand in the yard with my compass, the N
points north.
Problem: Every elementary school student knows that magnets
align themselves along opposite poles; north-south, but never
north-north or south-south. Thus, my third grade education leads me
to believe one of the following: The N on the compass is the South
Pole, or when I’m facing north, I’m facing the magnetic
South Pole of the Earth.
Question: Which is it? Is the N on the compass the South Pole,
or was Peary really the first to reach the SOUTH Pole?
You’ve got it! Here’s the way to remember: The needle on
the compass is a ‘North-Seeking’ needle. That means the
north point on the needle is actually charged south! This also
leads in to why some magnets have marked poles yet are charged
opposite the marks. Sometimes that means that the person who put
the initial charge in was not paying attention. Other times it may
have been an instruction to the assembly tech to ‘put this pole
on the north of the charger.’
As has been said before, a compass is used as a comparative
instrument, not an absolute one. After all, which way is up,
anyway?
Now that we’ve established the difference between
north and south, there’s the question of recharging
magnets.
That is a capacitive discharge type of charger. That is how rare
earth magnets are charged. In fact, you don’t need such thick
wire. You can use very thin wire, much smaller than is rated for
such a large current. The capacitor dumps a huge slug of current
through the windings for an instant. If you make your calculations
right, then the wire won’t melt. Kind of scary thinking that
you could dump 200 amps through 18-gauge wire (or whatever the
numbers come out to be), but that is how it is done.
I see how you can recharge horseshoe type magnets, but what
happens if they are in a flywheel, like with Maytag or Briggs &
Stratton engines? Do you have to remove them from the flywheel, or
is it possible to charge the magnets in place? Also, how do you
keep a keeper on the magnets while installing them?
Flywheel magnetos are usually charged with magnets in the
flywheel, and it generally requires a set of specialized ‘poll
pieces’ to make the connection to the charger.
Horseshoe magnets require a flat bar keeper, while flat bar
magnets require a horseshoe shaped keeper. In either case you leave
the keeper on the magnet until the magnet comes into contact with
the core of the assembled magneto. Magnetos of any type can be
charged as assembled units, or the magnets can be charged
separately and moved to the magneto with a keeper. Most magneto
guys use both methods of charging. Many of the old repair manuals
give charging the magnetos as the last step before returning the
magneto to service.
I hope this has clarified some of the mysteries of
magnetos. If you can make it to the Portland show, then be sure to
stop by the ATIS Stationary Engine List area to say hello. We have
a big banner identifying us, lots of national and state flags, and
plenty of unusual accents!
Engine enthusiast Helen French lives in Leicester,
England.
Contact her via e-mail at: Helen@insulate.co.uk You can join
the Stationary Engine List on the Internet at:
www.atis.net
