The basics of Spark Ignition are easy to grasp. The compressed fuel/air mixture drawn into your engine is detonated by an electrical spark, generated when the piston reaches Top Dead Centre (or within a few degrees). Now repeat - 100 times each second (6,000rpm)!
A majority of our IC Engines were developed to run with contact breaker points. CB point systems rely upon the profile of a rotating cam to open and close the gap between 2 tungsten "pads". Opening the points triggers the high tension coil to send a single jolt down the HT lead and across the spark plug gap. Kapow!!
This method survived in the automotive markets until around 1979, when Lucas, Bosch, Magnetti Marelli and Nipon Denso all changed over to transistorised, Hall Effect devices. Interestingly, the effect was discovered by Edwin Hall in 1879, 100 years before this application! The new devices signalled the demise of points and fiendishly clever auto-advance mechanisms. Overnight there was no gap to set, no mis-matched faces to arc and burn and no high speed points-bounce.
The TIM-6 kit brings the same advantages to model IC Engines. In place of the cam, a tiny rare earth magnet (Ø1/8" x 1/16" thick) is mounted on a drum or disc. As this magnet passes in close proximity to a remotely mounted sensor, the circuit board amplifies the current induced by the magnet and triggers the HT coil. Kapow again!
The TIM-6 system arrives as a kit of 10 electrical components, a circuit board (1" x 1 3/8" - easily hidden) and the necessary instructions. The TIM-6 system works at between 4.8 and 6.0V; compatible with the Exciter shown below and many other HT Coils.
One rare earth magnet comes with the kit so if you're building a single cylinder engine this is all you need. Otherwise, you should order one extra magnet for a twin, 3 extra magnets for 4 cylinders and so on.
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Tiny magnet - Ø1/8" x 1/16" thick. Very strong for its size. With the TIM-6 system above, you'll need extra magnets for multi-cylinder engines. Alternatively, if you know you're going to lose it, why not order a spare one in advance.....? Another tip: It is the South Pole of these magnets that must face the Hall effect sensor to trigger a spark. You can find the South Pole of the magnet using a hand held compass. You'll remember from school (no doubt?!) that the compass points to the earth's magnetic South Pole which is its geographical North Pole. |
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| Spark Plugs - Ready to Fit Ref: Plugs | |
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We stock 2 sizes of manufactured plugs:
Rimfire VR2 Spark Plug (1/4" x 32tpi)
Rimfire spark plugs were designed to outperform and replace the older generations of miniature spark plugs from the 1930s through the 1950s. Their physical sizes, designations, threads, and reach are nearly identical to the plugs that were most commonly used, but with added technological features to increase an engines performance. They are manufactured from the highest grades of material available and surpass that of most full-size automobile spark plugs.
This plug size is specified for the Aero V Twin, the Whippet, the Seagull, the Seal, the Seal Major and the Sealion engines. The VR2 will also run perfectly in the Atom Minor Mk3, the Phoenix, the Kiwi and the Wallaby even though these engines were originally designed to accept larger 3/8" x 24tpi plugs. Many constructors feel that the Rimfire VR2 is aesthetically more to scale.
Denso U20M-U (M10 x 1mm Pitch)
These are among the smallest mass manufactured plugs available and benefit from having a mass manufactured price. They are a suitable alternative for engines originally designed to accept 3/8" x 24tpi plugs that were commonly available in yester-year. In our engine range, they will suit the Kiwi, the Phoenix, the Atom Minor Mk3, the Wallaby and the Wyvern. The Denso U20M has a reach of 0.339" and the hex measures 13.8mm AF. The plug benenfits from a patented U-channel ground electrode.
Please choose:
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"Exciter" Ignition CoilRef: HEA 1100
UNFORTUNATELY... These coils are no longer available. Please bare with us as we locate a new supplier.
Before the advent of the 'Exciter', builders had to choose between Model Airplane, converted 'Magneto', Automotive or Motorcycle coils. The smallest, usually being the Model Airplane coil, was designed to be a low voltage, lightweight and economical device primarily suitable for use in lightweight model airplanes.
The "Exciter" coil is a compact, heavy duty, high output, multi-voltage ignition coil. It is fully protected from petrol, oil, water, dirt, vibration and impact. The coil will operate from 3.6 - 6.0V. Its dimensions are Ø1 3/8" x 1.9" long and it weighs just 4.3oz.
2 versions of the "Exciter" are now available, Standard and Twin-Spark. The conventional 3-wire, Standard version is suitable for single cylinder applications and all "multis" operating with a distributor mechanism. This includes every spark ignition engine in our range! The 4-wire coil is capable of being used for Twin-Spark operation, offering a simplified ignition for twin cylinder engines such as the Seagull, Wallaby and Aero V Twin by firing both plugs without a distributor. Supplied complete with suitable condenser, operating instructions and connection diagrams.
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Tungsten contact breaker points, once prolific in automotive ignition systems, have become virtually unobtainable in recent years. Tungsten is a robust, brittle metal with a high resistance to temperature and a high melting point - withstanding surface pitting for 100's of engine hours. By a happy chance, we have obtained a decent stock of solid tungsten discs measuring Ø0.160" x 0.045" thick with ground and polished faces. These can be easily brazed to spring steel or headless bolts with a silver based material such as Easyflo. In theory at least...the tungsten can be machined with a carbide tool run at 100 - 200 rpm with a good supply of coolant. |
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