Letters & Miscellanies

Notes and Responses From Readers

Hill diesel engines

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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 Hills.

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 often.

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 it.

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 projects.

John M. Edgerton, 27 Loon Lake Rd. Bigfork, MT 59911

(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 cover.

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 Charger.

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 insulations.

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 used.

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 1x1 -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., Topeka, KS 66609-1265, or e-mail: rbackus@ogdenpubs.com