How to Modify RC Engines
- 1). Clean and disassemble the engine, removing the piston sleeve. Note the various ports of the sleeve. The exhaust port in the sleeve is aligned with the exhaust flange in the engine block and is the highest port of the sleeve, opposite of which are the boost ports, and the ports located at the side of the sleeve (the transfer ports). The ports to be modified are the boost and transfer ports.
- 2). Examine the bottom of the piston sleeve. If the edge is square, use the dremel tool with a carbide cutting bit to round the edge, smoothing the air/fuel mixture flow. Round the edge using a low-speed setting on the tool, taking care to remove as little material as possible from the sleeve. Once you've shaped the edge, use a polishing bit to completely smooth the surface.
- 3). Examine the boost ports to determine if the ports already have a beveled edge or are cut directly into the sleeve. If the cut is direct, smooth the port cuts, beveling the edge from the outside using a carbide grinding bit. Do not modify the inner sleeve portion of the port, because this can change the port timing, altering engine performance negatively. Finish the edge using the polishing bit. This should help smooth the flow of the air/fuel mix into the engine. Some models come with a single boost port, which should be modified as directed.
- 4). Bevel and smooth the lower edges of the transfer ports. Bevel the outside edge with a carbide bit and then polish the edge smooth with the polishing bit.
- 5). Cut a guide port in the sleeve with a rotary tool at the side of the transfer port nearest the exhaust port, falling from the edge of the port to help guide the fuel/air flow into the port. The guide port should taper to a point as it approaches the bottom of the sleeve. Use a polishing wheel to polish smooth the transfer ports on the sleeve.
- 6). Clean the sleeve using the nitro cleaner, and then spray the surface of the sleeve with an air compressor. Repeat the process several times to remove any remaining flakes of metal that may damage the engine.
- 7). Spray the sleeve and engine parts with the spray lubricant and apply after-run oil to the engine bearings. Assemble the engine and remount it for use.
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