Letters & Miscellanies

By Staff
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Hill Diesels

Thanks for running my question in Reflections on Hill
diesel engines (see GEM, February 2002, page 10). I only got one
reply, but a good one. A Mr. Vincent referred me to Jack Heemsoth
of Marshall, Mich.

Jack wrote an article in GEM about Hill diesels (see GEM,
February 1997, page 25) and his 30,000 pounds of spare parts for

I have spoken to Jack several times and he is very helpful. He
knows a few collectors of Hill diesels, but 1 must say there are
very few people who know anything about Hills. Must not be very
popular with the collectors.

Art Schabla, 77427 Hwy. 21 Covington, LA 70435

Igniting Maytags

I read the letters under SmokStak (see GEM, February
2002, page 22) and agree with them wholeheartedly on the ignition
on Maytag engines. The only thing wrong is the information is 15
years too late for me. 1 had to find out the hard way through trial
and error. Until you’ve worked with them awhile, they can be
hard to start.

My collecting began about 17 years ago. I’ve collected
Maytags from Arizona, Florida, Texas, Washington and Canada, but
mostly from Iowa and Kansas. So far, I’ve acquired 618 that
have run and burned a tank full of gas. I have sold down to about
600 now.

I also made two tractors with Maytag motors, and I have junked
about 400 Maytags.

Dale Luttig, 9565 Hwy. 63 Emmett, KS 66422

Spark Plugs

With reference to the letter from Donald McKinsey in the March
2002 issue pertaining to spark plugs:

I think it might be helpful to this discussion if we consider
what we want a spark plug to do. When the design engineer worked up
specs for any given engine, he was expecting it to develop good
power, good fuel economy and long life with a nominal amount of
maintenance. He probably tried several spark plugs with various
heat ranges in his development trials and settled on his
recommended plug based on its firing well and not fouling too

Dale Luttig sends this photo as proof of his claim to owning 618
Maytag engines at one time. Look closely, because there are engines
in the shadow of his shop.

The harder an engine is pulled, the colder the plug you can and
should use. Most of us aren’t really working these engines
anymore. We like them to start easily and sit and idle for hours
because we like the stack music. Cinder these conditions the
interval between pops is greater and the charge is much less dense,
resulting in the plug running much colder. Consequently, it
doesn’t keep burned clean and it soots up. Also, many of these
engines are worn considerably and are burning more oil, which tends
to foul plugs. Both situations are likely to be helped with a
hotter plug.

A trick I find quite helpful when a plug does foul is to burn it
clean with an acetylene welder. I just insert the porcelain end in
the pipe handle of the welder cart, use the smallest tip I have,
preheat the threaded end on the outside, then carefully direct the
flame inside on the shell as well as the porcelain. Be careful you
don’t burn off the side electrode. You will see the carbon
deposits vaporize off and ignite. This does a good job, and if you
think about it, you are creating the same conditions for the plug
electrodes as they see in a working cylinder.

C.R. Umback, P.O. Box 117 Lemmon, SD 57638

Comments on GEM

In your Hit-and-Miss column you asked for some
comments, so here are mine.

First off, why do you have to put headlines on the covers of the
magazine? You are covering up parts of a beautiful color picture of
an engine. The cover reminds me of a supermarket tabloid. believe
most subscribers don’t care about the headlines on stories that
are inside. We know what the magazine is about; you can’t buy
the magazine on a newsstand that I know of, so why waste time doing

Also, some of us senior citizens do not own a computer and
don’t wish to, so we are left out when it comes to expressing
our views on the Stationary Engine List and on SmokStak.
If we knew in advance what the subject was, people like me could
send in our comments.

Other than these things the magazine gets a score of 8 from me.
Only wish there were more articles written by subscribers on their

John M. Edgerton, 27 Loon Lake Rd. Bigfork, MT

(Starting with the March 2002 issue, GEM hit the news stand for
the first time, and it’s now available at Tractor Supply Co.
stores in the Midwest. We’re very excited about getting GEM on
newsstands, and that was part of putting headlines on the

As for the Stationary Engine List and SmokStak columns, what you
complain about is actually the beauty of those Internet bulletin
boards. The conversational threads we present here occur
unpredictably, and tend to take on a life of their own as they
build. They are not planned, nor can they be, and the idea is to
share with readers what’s happening in the old iron hobby on
the Internet – Editor)

‘REX’ Magnet Charger

I have some comments and updates regarding the March 2002
article on Building Magnet Chargers, and specifically on
my January 1989 GEM article, How to Build a Heavy Duty Magneto

Fifteen years ago when I designed the heavy-duty magneto charger
Formvar covered magnet wire was more available than today. Magnet
wire is nothing more than a pure copper wire with a thin film
coating. The use of a thin coating is important, because more turns
of wire can be wound in a given space than with thicker

Typical coatings are designed for service temperatures ranging
from 105 to 220 degrees C. Because they run hot, electric motors,
transformers, etc., require insulations that won’t fail at the
higher temperature. However, the magnet charger operates at room
temperature, and any class of insulation is satisfactory. I would
recommend a heavy (double) coated wire, as it is more rugged than
single coated wire. Insulations such as polyurethane, polyvinyl
formal (Formvar), polyester, polyester-amide-imide and polyimide
are all suitable. Manufacturers assign their own trade names to
these insulations, but virtually any heavy film insulated magnet
wire is suitable.

Knife switches are somewhat hard to locate today, however,
automotive parts suppliers have small, high-current knife switches
for use in under hood battery disconnect applications. J.C. Whitney
(mail order), and many local auto parts stores sell these, and they
could be adapted to the application. An automotive starter solenoid
with a push button switch to actuate the solenoid could also be

Steel for the charger can be any ‘soft,’ easy to machine
steel. C1018 was recommended for the original design, but
‘Ledloy,’ 12L14, B1113, hot-rolled steel, cold-rolled
steel, would all be suitable. The saturation flux density for all
of these is well over 10,000 gauss. There will be some residual
magnetism remaining in the steel after turning off the charger, but
this is of no consequence.

Pole piece size and coil core diameter should have at least as
much cross sectional area as the pole shoe and core area of the
largest magneto to be charged. This assures that the charger poles
themselves don’t saturate. For this reason, I chose to use
3-inch diameter charger poles in the original charger. This allows
sufficient area to saturate the frame and magnets on a large
magneto, such as the Bosch D with six magnets.

With adequate pole piece area, all that is necessary is to
develop sufficient amp-turns (magnetizing force) to saturate the
magneto core and associated magnets. The original design with about
20,000 amp-turns has worked well for the last 15 years. To date, I
have not found a magneto that this charger would not charge. If a
day should come that more energy is needed, I could double the
battery voltage to 24 volts and develop 40,000 amp-turns.

In World War I, the British Thompson Houston (BTH) company type
AV magneto was magnetized by passing a solid copper bar 1×1 -inch
through the arch of the magnet on the assembled magneto. A
momentary current of 7,000 amps was then applied through the bar.
This (7,000 amp-turns) was sufficient to fully charge the magnet.
In this case, the magnet was fully saturated without the necessity
of saturating the pole shoes and armature as they are in a series
magnetic circuit with the magnets.

Obviously, a great deal of specialized equipment was necessary
for magnetizing in this way. A unipolar dynamo capable of supplying
one volt and 10,000 amperes was used along with massively heavy
interconnecting wires and switch.

It’s critical to understand the importance of charging any
magneto that has had either the magnets or armature removed.
It’s equally important to charge the fully assembled magneto,
rather than charging individual magnets and placing them on the
magneto. For more on this subject see my GEM article on page 11 of
the November 1986 issue, How Often Do magnetos Need Recharging?
John Rex 12 Gail St. Chelmsford, MA 01824

Send letters to: Gas Engine Magazine, 1503 SW 42nd St.,
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