Sep 25, 2012 Here is a project I have had on the back burner for a while. Skip navigation Sign in. Wico EK Magneto Repair magnet charger 16of - Duration: 12:24. Shopdogsam 17,689 views.

• How To Build A Magneto
• Magnetizer Demagnetizer How To Use
• Magneto Remagnetizing Service

Build a Magneto Magnetizer, Gingery, David J, ISBN Build a Magneto Magnetizer Many people collect and restore old engines and in the process discover that the old iron magnets in the magneto. How to Build a Magneto Magnetizer by David J. Gingery available in Pamphlet on, also read synopsis and reviews.

1934 supercharged at 2009 Problems playing this file? A supercharger is an air that or supplied to an. This gives each intake cycle of the engine more oxygen, letting it burn more and do more, thus increasing power. Power for the supercharger can be provided mechanically by means of a belt, gear, shaft, or chain connected to the engine's.

Common usage restricts the term to mechanically driven units; when power is instead provided by a powered by, a supercharger is known as a or just a turbo - or in the past a turbosupercharger. Lysholm screw rotors with complex shape of each rotor, which must run at high speed and with close tolerances. This makes this type of supercharger expensive. (This unit has been to show close contact areas.) Positive-displacement pumps deliver a nearly fixed volume of air per revolution at all speeds (minus leakage, which is almost constant at all speeds for a given pressure, thus its importance decreases at higher speeds). Major types of positive-displacement pumps include:., also known as the G-Lader Compression type. This section does not any.

Unsourced material may be challenged. ( May 2010) Positive-displacement pumps are further divided into internal and external compression types.

Roots superchargers, including high helix roots superchargers, produce compression externally. External compression refers to pumps that transfer air at ambient pressure. If an engine equipped with a supercharger that compresses externally is running under boost conditions, the pressure inside the supercharger remains at ambient pressure; air is only pressurized downstream of the supercharger. Roots superchargers tend to be very mechanically efficient at moving air at low pressure differentials, whereas at high pressure rations, internal compression superchargers tend to be more mechanically efficient. All the other types have some degree of internal compression. Internal compression refers to the compression of air within the supercharger itself, which, already at or close to boost level, can be delivered smoothly to the engine with little or no back flow.Internal compression devices usually use a fixed internal compression ratio.

When the boost pressure is equal to the compression pressure of the supercharger, the back flow is zero. If the boost pressure exceeds that compression pressure, back flow can still occur as in a roots blower. The internal compression ratio of this type of supercharger can be matched to the expected boost pressure in order to optimize mechanical efficiency.

Capacity rating Positive-displacement superchargers are usually rated by their capacity per revolution. In the case of the Roots blower, the GMC rating pattern is typical. The GMC types are rated according to how many two-stroke cylinders, and the size of those cylinders, it is designed to scavenge. GMC has made 2–71, 3–71, 4–71, and the famed 6–71 blowers. For example, a 6–71 blower is designed to scavenge six cylinders of 71 cubic inches (1,163 cc) each and would be used on a two-stroke diesel of 426 cubic inches (6,981 cc), which is designated a 6–71; the blower takes this same designation.

However, because 6–71 is actually the engine's designation, the actual displacement is less than the simple multiplication would suggest. A 6–71 actually pumps 339 cubic inches (5,555 cc) per revolution (but as it spins faster than the engine, it can easily put out the same displacement as the engine per engine rev). Aftermarket derivatives continue the trend with 8–71 to current 16–71 blowers used in different motor sports.

From this, one can see that a 6–71 is roughly twice the size of a 3–71. GMC also made 53 cu in (869 cc) series in 2–, 3–, 4–, 6–, and 8–53 sizes, as well as a 'V71' series for use on engines using a V configuration.

Dynamic Dynamic compressors rely on accelerating the air to high speed and then exchanging that velocity for pressure by diffusing or slowing it down. Major types of dynamic compressor are:. Supercharger drive types Superchargers are further defined according to their method of drive.

Belt (V-belt, Synchronous belt, Flat belt). Direct drive.

Gear drive. Chain drive Temperature effects and intercoolers. 1929 'Blower'. The large 'blower' (supercharger), located in front of the radiator, gave the car its name. In 1900, of , was the first to patent a forced-induction system for internal combustion engines, superchargers based on the twin-rotor air-pump design, first patented by the American in 1860, the basic design for the modern. The first supercharged cars were introduced at the 1921: the 6/20 hp and 10/35 hp.

These cars went into production in 1923 as the 6/25/40 hp (regarded as the first supercharged road car ) and 10/40/65 hp. These were normal road cars as other supercharged cars at same time were almost all racing cars, including the 1923 805-405, 1923 122 1924, 1924, 1925, and the 1926. At the end of the 1920s, made a supercharged version of the road car.

Since then, superchargers (and turbochargers) have been widely applied to racing and production cars, although the supercharger's technological complexity and cost have largely limited it to expensive, high-performance cars. Supercharging versus turbocharging. Keeping the air that enters the engine cool is an important part of the design of both superchargers and turbochargers. Compressing air increases its temperature, so it is common to use a small radiator called an between the pump and the engine to reduce the temperature of the air. There are three main categories of superchargers for automotive use:. Centrifugal turbochargers – driven from exhaust gases. Centrifugal superchargers – driven directly by the engine via a belt-drive.

Positive displacement pumps – such as the, (Lysholm), and blowers. Roots blowers tend to be only 40–50% efficient at high boost levels; by contrast centrifugal (dynamic) superchargers are 70–85% efficient at high boost. Lysholm-style blowers can be nearly as efficient as their centrifugal counterparts over a narrow range of load/speed/boost, for which the system must be specifically designed. Mechanically driven superchargers may absorb as much as a third of the total crankshaft power of the engine and are less efficient than turbochargers. However, in applications for which engine response and are more important than other considerations, such as and vehicles used in competitions, mechanically driven superchargers are very common. The, or fraction of the fuel/air energy that is converted to output power, is less with a mechanically driven supercharger than with a turbocharger, because turbochargers use energy from the exhaust gas that would normally be wasted.

For this reason, both economy and the power of a turbocharged engine are usually better than with superchargers. Turbochargers suffer (to a greater or lesser extent) from so-called (turbo lag; more correctly, boost lag), in which initial acceleration from low RPM is limited by the lack of sufficient exhaust gas (pressure). Once engine RPM is sufficient to raise the turbine RPM into its designed operating range, there is a rapid increase in power, as higher turbo boost causes more exhaust gas production, which spins the turbo yet faster, leading to a belated 'surge' of acceleration. This makes the maintenance of smoothly increasing RPM far harder with turbochargers than with engine-driven superchargers, which apply boost in direct proportion to the engine RPM. The main advantage of an engine with a mechanically driven supercharger is better response, as well as the ability to reach full-boost pressure instantaneously. With the latest turbocharging technology and direct gasoline injection, throttle response on turbocharged cars is nearly as good as with mechanically powered superchargers, but the existing lag time is still considered a major drawback, especially considering that the vast majority of mechanically driven superchargers are now driven off clutched pulleys, much like an air compressor.

Turbocharging has been more popular than superchargers among auto manufacturers owing to better power and efficiency. For instance and previously had supercharged offerings in the early 2000s such as the C230K, C32 AMG, and S55 AMG, but they have abandoned that technology in favor of turbocharged engines released around 2010 such as the C250 and S65 AMG biturbo.

However, Audi did introduce its 3.0 TFSI supercharged V6 in 2009 for its A6, S4, and Q7, while Jaguar has its supercharged V8 engine available as a performance option in the XJ, XF, XKR, and F-Type, and, via joint ownership by Tata motors, in the Range Rover also. Twincharging In the 1985 and 1986 World Rally Championships, Lancia ran the, which incorporated both a belt-driven supercharger and exhaust-driven turbocharger.

How To Make A Magnetizer

The design used a complex series of bypass valves in the induction and exhaust systems as well as an electromagnetic clutch so that, at low engine speeds, boost was derived from the supercharger. In the middle of the rev range, boost was derived from both systems, while at the highest revs the system disconnected drive from the supercharger and isolated the associated ducting. This was done in an attempt to exploit the advantages of each of the charging systems while removing the disadvantages.

In turn, this approach brought greater complexity and impacted on the car's reliability in WRC events, as well as increasing the weight of engine ancillaries in the finished design. The Volkswagen TSI engine (or ) is a 1.4-litre direct-injection motor that also uses both a supercharger and turbocharger. Aircraft Altitude effects. A Centrifugal supercharger of a aircraft engine. Superchargers are a natural addition to that are intended for operation at high altitudes. As an aircraft climbs to higher altitude, air pressure and decreases.

The output of a piston engine drops because of the reduction in the mass of air that can be drawn into the engine. For example, the air density at 30,000 ft (9,100 m) is ​ 1⁄ 3 of that at, thus only ​ 1⁄ 3 of the amount of air can be drawn into the cylinder, with enough oxygen to provide efficient combustion for only a third as much fuel. So, at 30,000 ft (9,100 m), only ​ 1⁄ 3 of the fuel burnt at sea level can be burnt. (An advantage of the decreased air density is that the airframe experiences only about 1/3 of the. In addition, there is decreased back pressure on the exhaust gases.

On the other hand, more energy is consumed holding an airplane up with less air in which to generate lift.) A supercharger can be thought of either as artificially increasing the density of the air by compressing it or as forcing more air than normal into the cylinder every time the piston moves down. A supercharger compresses the air back to sea-level-equivalent pressures, or even much higher, in order to make the engine produce just as much power at cruise altitude as it does at sea level. With the reduced aerodynamic drag at high altitude and the engine still producing rated power, a supercharged airplane can fly much faster at altitude than a naturally aspirated one. The pilot controls the output of the supercharger with the throttle and indirectly via the propeller governor control. Since the size of the supercharger is chosen to produce a given amount of pressure at high altitude, the supercharger is oversized for low altitude. The pilot must be careful with the throttle and watch the manifold pressure gauge to avoid overboosting at low altitude. As the aircraft climbs and the air density drops, the pilot must continuously open the throttle in small increments to maintain full power.

The altitude at which the throttle reaches full open and the engine is still producing full rated power is known as the critical altitude. Above the critical altitude, engine power output will start to drop as the aircraft continues to climb. Effects of temperature. Supercharger CDT vs. Graph shows the CDT differences between a constant-boost supercharger and a variable-boost supercharger when utilized on an aircraft.

As discussed above, supercharging can cause a spike in temperature, and extreme temperatures will cause of the fuel-air mixture and damage to the engine. In the case of aircraft, this causes a problem at low altitudes, where the air is both denser and warmer than at high altitudes. With high ambient air temperatures, detonation could start to occur with the manifold pressure gauge reading far below the red line. A supercharger optimized for high altitudes causes the opposite problem on the intake side of the system.

With the throttle retarded to avoid overboosting, air temperature in the can drop low enough to cause ice to form at the throttle plate. In this manner, enough ice could accumulate to cause engine failure, even with the engine operating at full rated power. For this reason, many supercharged aircraft featured a carburetor air temperature gauge or warning light to alert the pilot of possible icing conditions. Several solutions to these problems were developed: and aftercoolers, two-speed superchargers, and two-stage superchargers. Two-speed and two-stage superchargers In the 1930s, two-speed drives were developed for superchargers for aero engines providing more flexibility aircraft operation. The arrangement also entailed more complexity of manufacturing and maintenance.

The gears connected the supercharger to the engine using a system of hydraulic clutches, which were initially manually engaged or disengaged by the pilot with a control in the cockpit. At low altitudes, the low-speed gear would be used in order to keep the manifold temperatures low. At around 12,000 feet (3,700 m), when the throttle was full forward and the manifold pressure started to drop off, the pilot would retard the throttle and switch to the higher gear, then readjust the throttle to the desired manifold pressure. Later installations automated the gear change according to atmospheric pressure. In the the Spitfire and Hurricane planes powered by the engine were equipped largely with single stage and single speed superchargers. Of, to improve the performance of the Merlin engine developed two-speed two-stage supercharging with aftercooling with a successful application on the aero engine in 1942.

Horsepower was increased and performance at all aircraft heights. Hooker's developments allowed the aircraft they powered to maintain a crucial advantage over the German aircraft they opposed throughout World War II despite the German engines being significantly larger in displacement. Two-stage superchargers were also always two-speed. After the air was compressed in the low-pressure stage, the air flowed through an radiator where it was cooled before being compressed again by the high-pressure stage and then possibly also aftercooled in another. Two-stage compressors provided much improved high altitude performance, as typified by the Rolls-Royce Merlin 61 powered Mk IX and the.

In some two-stage systems, damper doors would be opened or closed by the pilot in order to bypass one stage as needed. Some systems had a cockpit control for opening or closing a damper to the intercooler/aftercooler, providing another way to control temperature. Rolls-Royce Merlin engines had fully automated boost control with all the pilot having to do was advance the throttle with the control system limiting boost as necessary until maximum altitude was reached. Turbocharging. Main article: A mechanically driven supercharger has to take its drive power from the engine.

Taking a single-stage single-speed supercharged engine, such as an early, for instance, the supercharger uses up about 150 (110 ). Without a supercharger, the engine could produce about 750 (560 ), but with a supercharger, it produces about 1,000 hp (750 kW)—an increase of about 400 hp (750 - 150 + 400 = 1000 hp), or a net gain of 250 hp (190 kW). This is where the principal disadvantage of a supercharger becomes apparent. The engine has to burn extra fuel to provide power to drive the supercharger.

The increased air density during the input cycle increases the of the engine and its, but at the cost of an increase in the of the engine. In addition to increasing the cost of running the a supercharger has the potential to reduce its overall range for a specific fuel load. As opposed to a supercharger driven by the engine itself, a is driven using the otherwise wasted exhaust gas from the engine. The amount of power in the gas is proportional to the difference between the exhaust pressure and air pressure, and this difference increases with altitude, helping a turbocharged engine to compensate for changing altitude.

This increases the height at which maximum power output of the engine is attained compared to supercharger boosting, and allows better fuel consumption at high altitude compared to an equivalent supercharged engine. This facilitates increased at high altitude and gives a greater operational range than an equivalently boosted engine using a supercharger. The majority of aircraft engines used during used mechanically driven superchargers, because they had some significant manufacturing advantages over turbochargers.

Magneto Magnetizer For Sale

However, the benefit to operational range was given a much higher priority to American aircraft because of a less predictable requirement on operational range, and having to travel far from their home bases. Consequently, turbochargers were mainly employed in American aircraft engines such as the and the, which were comparably heavier when turbocharged, and required additional ducting of expensive high-temperature in the and preturbine section of the exhaust system. The size of the ducting alone was a serious design consideration.

For example, both the and the used the same, but the large barrel-shaped fuselage of the turbocharged P-47 was needed because of the amount of ducting to and from the turbocharger in the rear of the aircraft. The F4U used a two-stage intercooled supercharger with more compact layout. Nonetheless, turbochargers were useful in high-altitude and some fighter aircraft due to the increased high altitude performance and range. Turbocharged piston engines are also subject to many of the same operating restrictions as those of gas turbine engines.

Turbocharged engines also require frequent inspections of their turbochargers and exhaust systems to search for possible damage caused by the extreme heat and pressure of the turbochargers. Such damage was a prominent problem in the early models of the American high-altitude used in the during 1944–45. Turbocharged piston engines continued to be used in a large number of postwar airplanes, such as the, the, the, the, and the. In more recent times most aircraft engines for (light airplanes) are, but the smaller number of modern aviation piston engines designed to run at high altitudes use turbocharger or turbo-normalizer systems, instead of a supercharger driven from the crank shafts. The change in thinking is largely due to economics. Was once plentiful and cheap, favoring the simple but fuel-hungry supercharger. As the cost of fuel has increased, the ordinary supercharger has fallen out of favor.

Also, depending on what factor one uses, fuel costs have not decreased as fast as production and maintenance costs have. Effects of fuel octane rating Until the late 1920s all automobile and aviation fuel was generally rated at 87 or less. This is the rating that was achieved by the simple distillation of 'light crude' oil. Engines from around the world were designed to work with this grade of fuel, which set a limit to the amount of boosting that could be provided by the supercharger, while maintaining a reasonable compression ratio. Boosting through additives was a line of research being explored at the time.

Using these techniques, less valuable crude could still supply large amounts of useful gasoline, which made it a valuable process. However, the additives were not limited to making poor-quality oil into 87-octane gasoline; the same additives could also be used to boost the gasoline to much higher octane ratings. Higher-octane fuel resists and better than does low-octane fuel.

As a result, the amount of boost supplied by the superchargers could be increased, resulting in an increase in engine output. The development of 100-octane aviation fuel, pioneered in the USA before the war, enabled the use of higher boost pressures to be used on high-performance aviation engines, and was used to develop extremely high-power outputs – for short periods – in several of the pre-war speed record airplanes. Operational use of the new fuel during World War II began in early 1940 when 100-octane fuel was delivered to the British from refineries in America and the East Indies.

The German also had supplies of a similar fuel. Increasing the knocking limits of existing aviation fuels became a major focus of aero engine development during World War II. By the end of the war, fuel was being delivered at a nominal 150-octane rating, on which late-war aero engines like the 66 or the DC developed as much as 2,000 hp (1,500 kW). See also. Notes. Retrieved 2010-08-03. Great Britain: Institution of Mechanical Engineers.

1974-01-01 – via Google Books. Ian McNeil, ed. London: Routledge. David Boothroyd, The VU. Archived from on 2004-12-15. Retrieved 2005-01-19. The new encyclopedia of motorcars 1885 to the present (ed.3.

New York: Dutton. Retrieved 2015-10-23.

Kenne Bell. Retrieved 2009-01-21. Retrieved 2009-01-21. Retrieved 2009-01-21. Retrieved 2009-01-21. Retrieved 2009-01-21. Retrieved 2014-03-04.

^ Smallwood 1995, p.133. Northrop 1955, p.111.

^ preface. Payton-Smith 1971, pp. Mankau and Petrick 2001, pp. Griehl 1999, p. Price, 1982. Berger & Street, 1994. Mermet 1999, pp.

Mermet 1999, p. References. White, Graham. Allied Aircraft Piston Engines of World War II: History and Development of Frontline Aircraft Piston Engines Produced by Great Britain and the United States during World War II. Warrendale, Penn: Society of Automotive Engineers, Inc.; Shrewsbury, England: Airlife Publishing Ltd.; 1995.,.

External links Wikimedia Commons has media related to. by Bill Harris at HowStuffWorks.com., a large article from, June 1941. by Whipple Superchargers. a 1943 Flight article.

Below left is the winding machine we use for winding primary coils. There are usually only 3 to 5 layers of a relatively heavy wire so it is done by hand winding. Below right is the machine used for winding secondary coils.

Here, we are looking at, usually, 9 to 15 thousand turns of very fine wire - perhaps only 2 or 3 thousandths of an inch in diameter. Because of this, the machine is motor driven. The variac on the left controls the winding speed. The unit shown on the top of the wire coil controls the wire tension. We have standardised all our winding machines so that they hold the coil core between centres. Many cores, particularly from rotating armature magnetos, already have centre holes either from original manufacture or they have been added by other re-winders since.

If we do need to drill a centre hole, we use this machine - dedicated to this one operation. The core is held in a special centering vice. Based on a commercially available self centering vice which centres the core from front to back, we have modified it with the addition of two side locator plates.

These plates run on a rack and pinion arrangement so that they automatically centre the core from side to side as well. Some will be of the opinion that drilling a hole in the core will impair it's magnetic properties. From a theoretical point of view, this is probably correct but in practice a small 1.5mm diameter hole a couple of millimetres deep is very unlikely to make any measurable difference. Sometimes, a method which makes the job quick and accurate takes priority. The modifications we have made allow both radial and axial slots to be ground.

The cam ring holder can be either rotated or moved in a linear direction. One of these operations is locked while the other is in use. The picture below left shows how a series of plunge cuts can be made and then the base of the wide slot is flattened out by rotating the cam ring holder between a pair of adjustable stops. The picture below right shows how an axial slot is ground, again with a series of plunge cuts and then linear movement of the cam ring holder up to an adjustable stop flattens the bottom of the slot.

..

'How often do magnetos need recharging?' is a question frequently asked by antique engine enthusiasts. The answer has to do with the permanence of the magnet on the magneto. Magnets are mysterious to us because the magnetic field cannot be detected by any of the five senses, yet it does exist and has many powers. It can attract metal objects, convert mechanical energy to electrical energy, and vice versa, and even alter the normal characteristics of materials.

It is a common fallacy that a permanent magnet expends internal energy to create electricity from a magneto or generator. This fallacy leads to the belief that after repeated use the magnetism will all be used up and hence the magnet must be recharged. The energy to create the spark comes not from the magnet, but from the mechanical energy required to drive the magneto. The magnet merely acts to convert this mechanical energy to electrical energy.

Confidence in the permanency of permanent magnets is substantiated by evidence of the many applications they have been put to over the years. For example, magnets are present in compasses but they never wear out or need recharging. The continued accuracy of some of the most exacting scientific electrical measuring instruments such as the familiar speedometer also depends upon a permanent magnet remaining constant.

Most magnetos on hit and miss engines used magnets that were made of quench hardened steel alloyed with chrome, cobalt, or tungsten. Magnets of this material were made from rolled stock by forming or cutting into the shape of a horseshoe or long bar. Immediately after quench-hardening, the material was rather unstable metallurgically and considerable change in magnetism could occur if magnetized during this transition period. Fortunately most manufacturers allowed for proper aging after quenching and before magnetizing. There is probably some reduction in magnetism over the decades; however, it is minimal and probably only results in about one third loss at the most. Such a loss would hardly prevent a well-designed magneto from functioning adequately.

How To Build A Magneto

Owners of antique engines sometimes report that their magneto has mysteriously lost its magnetism. In most cases, the fact that the magnetism has been lost cannot be questioned; however, the 'mysterious' aspect can be disputed. There is nothing mysterious about it. If a piece of material can be magnetized, it is likewise capable of being demagnetized. There are definite and logical reasons why magnets lose their magnetism. The most common cause for these losses is that the magnets have been subjected to demagnetizing forces.

Investigation into how this happens usually uncovers at least one of the following:

1) Take the case of an engine enthusiast who wants to get the maximum performance out of his magneto. He removes the magnets, takes them to his local magneto service center for recharging, then puts them back on the mag. Now he gets a weaker spark than before. Why? Because removing the magnets subjects them to demagnetizing forces, the recharging restored the magnetism, but they again lost some of their magnetism upon removal from the charger. What's the right way to recharge them? Charge them on the magneto as an assembly. Removing the magnets from a magneto causes them to lose some of their magnetism.

It is possible to remove the magnets without weakening them by first installing a 'keeper' across the poles. The keeper should be a material which conducts magnetism well, such as soft iron. The keeper 'short circuits' the magnet and prevents charge loss during removal. One difficulty is that a keeper frequently must be a complex shape so the magnets can be removed while the keeper is across them. Magneto repair stations usually don't bother with keepers, because they recharge the magnets after all magneto work is completed (I usually totally demagnetize the magnets when working on magnetos so they won't pick up iron filings, magnetize tools, etc.)

2) Don't pile several magnetos together in a heap or pile. Having magnets close together can cause them to partially demagnetize each other. Keep magnetos away from each other by at least 3 inches.

3) Don't connect a battery to the terminals of a low tension magneto. The current can demagnetize the magnets and might burn out the coils. If you want to run a mag-equipped engine on a battery and coil, make sure the mag lead is disconnected so battery current will not demagnetize the magnets.

4) Don't remove the armature or rotor from a magneto because the magnets can be weakened. The rotor can be safely removed by first installing a 'keeper' across the end of the magnet poles. Leave the keeper in place until the rotor is replaced. The Wico EK mag is an exception to this rule and the armature may be safely removed and replaced without using a keeper.

5) Magnets which have been exposed to a fire or excessive heat will frequently lose their heat treatment and hence their magnetic characteristics. Such magnets may never recover their magnetism even when recharged because the characteristics of the metal have been altered.

6) Don't attempt to recharge magnets by methods which produce inadequate energy to fully recharge them. Wrapping a few turns of wire around the magnets and 'flashing ' the wire with an automotive battery or arc welder frequently exposes the magnets to demagnetizing forces and may weaken them rather than improve them. If recharging is required, it's best to use a magnet charger specifically designed for the purpose.

It is rumored that shock and vibration may demagnetize magnets, however I have never been able to observe this effect, even on early hardened magnet materials. I have seen magnetos that were dropped and the shock of the impact cracked the magnets, yet the mag still functioned, provided the magnets remained intact. In some cases after breakage the magnets will not stay in place. In cases like this, the magnets can be arc welded back together and still work adequately. Use a mild steel arc electrode with good penetration such as E6011 and place small tack welds at each end of the crack. Don't weld across the entire crack as too much heat will anneal excessive amounts of material and reduce the effectiveness of the magnet. Recharging after welding is required. Torch welding produces too much heat and should not be used.

Engines manufactured after World War II contained magnets that were usually made of Alnico (aluminum nickel cobalt) and are much more stable than quench-hardened steel alloy magnets. Special charging techniques must sometimes be used to adequately charge Alnico; however it is also much more resistant to demagnetization effects and almost never needs recharging. These modern magnets are usually short and small, internal to the magneto and are not visible from the outside. Alnico is not rolled from bar stock but is cast and has a rough surface texture except for the pole ends which are usually precision ground.

The answer to the question 'How often do magneto magnets need recharging?' depends on many factors. If the engine isn't running and all electrical and mechanical items have been tested and eliminated as possible sources of trouble, then the magnets have probably been exposed to demagnetizing forces as mentioned above and recharging is recommended. I would recharge quench-hardened magnets on general principles if a magnet charger is readily available. If you're going to the effort of having the magnets charged, make sure that all mechanical and electrical work, painting, etc. is finished before charging so that some charge won't be lost upon disassembly. If a magnet charger is not available and the magneto is working, I would use the rule which applies to all things and is, 'if it works, don't fix it!'

About The Author

Stop by any major New Hampshire or Massachusetts engine show and chances are good that you'll find John Rex there offering magneto charging, magneto advice and limited magneto service all at no cost. John's interest in magnetos and old engines started about 5 years ago in 1981 after he found an old Fairbanks Morse 'Z' on a friend's Lake Champlain property. The engine, purchased about 1928, was used to supply electricity for pumping lake water. She never would sell John the engine, but this started his interest and he now has about 15 old engines and dozens of magnetos in his collection.

'One thing I noticed at engine shows was that no one seemed to have much knowledge about magnetos used on antique engines and if there were mag problems, people didn't know what to do.' An electrical engineer by training, John decided to help people with mag problems. Last year (1985), he designed and built a heavy-duty portable magneto charger (it weighs over 150 lbs.) and started offering free charging at local engine shows where the service was an instant success.

'I was charging magnetos from early morning until after dark at this year's Orange, Mass. show. On Sunday, I finally had to say the heck with it and take an hour off just to see the show.'

Magnetizer Demagnetizer How To Use

John occasionally does mag work at home, but since it's a hobby and not a profession, he limits his work to shows. The old mags and mag literature, much of which has been donated to his collection, provides a base for knowledge and a source of parts. He encourages people to do their own mag work and offers pointers on how to best accomplish it.

Magneto Remagnetizing Service

John is doing research on the Webster Hi Tension magneto and would like to correspond with anyone who has information on these or their history. He wrote this article to answer some of the frequently asked questions about magneto charging.