The glow plug is a vital component in model and radio-controlled engines. The platinum coil inside the steel body of the glow plug heats up until it is red-hot, which gives the coil its name. The coil then combusts the fuel to run the engine. This plug is initially heated by a battery using a couple of volts. Once the coil is heated, it can maintain that heat using the power of the engine. By their nature glow plugs burn out fairly quickly. As such, owners often need a replacement glow plug for your RC engine.
Glow Plug Temperature
Glow plugs come in a variety of temperatures, with different temperatures being ideal for different situations. You can purchase a plug as hot, medium, cold, or very cold. Hot plugs are best for engines that use fuel with 80 per cent or more methanol content. A medium plug is best for 70 to 75 per cent, and a cold plug for 60 to 75 per cent. Generally: the more nitro in the fuel, the hotter the fuel and thus, the colder the plug should be. For anything lower than 65 per cent, go with a very cold plug. Hot plugs generally perform better in engines for off-road vehicles, and engines tend to handle idling and acceleration better with hot plugs. A cold plug is more powerful and better for engines that overheat frequently.
Standard Versus Turbo Glow Plugs
When replacing the glow plug in an RC engine, check to see if it uses standard or turbo plugs. A turbo glow plug engine requires a plug that has M8 x .75 mm threading; these plugs are 17 mm long and 9 mm in diameter. Conversely, standard glow plugs are 20.32 mm long and 9 mm in diameter, with 1/4-32 UNEF threading. These plug types are not interchangeable. Trying to install the wrong parts in your engine can damage the glow plug and potentially your engine.
Choosing Your Glow Plug
Choose your glow plug based not only on your engine and the plug temperature you require, but also the materials available. The coil is a vital part of the glow plug; a plated coil will wear out faster than a coil made from platinum alloy. When you find the right glow plug, purchase at least four or five, if not more; glow plugs burn out fairly regularly, and having a replacement on hand ensures that you have more of the plug that works. It may be a good idea to keep a variety of glow plug temperatures. With weather changes your engine may perform better with a different temperature glow plug. Always take proper precautions when removing an old glow plug, and when installing a new one. Wear safety gloves, and make sure the old glow plug has had time to cool.