what is runnings on nitromethane fuel
►  The nitromethane contained in model engine fuel has a unambiguous positive influence not only for engine output, but also generally to its function. The engine runnings on the fuel with nitromethane, it run " more soft", more regularly, the engine needs lower compression ratio for correct function, it runs more cold and  holds lower idle more reliable. If the nitromethane fuel is much more better for two stroke engines compare to the no nitromethane ones, it is quite neccessary for four stroke engines. Quite specific situation is as about the racing cars, racing hydroplanes and helicopters, where the relative high % of nitromethane is absolutely neccessary. Naturally it is true only at the presumption, that the engine is corectly set for concrete content of nitromethane used (mainly, it must have a correct compression ratio, although the basic design of engine, for example the timing, must be corresponding with used % of nitromethane also. So if a producer recommend for concrete type of engine to use 10 -  20% of nitromethane, it is not meaned that the engine will not run on no nitromethane fuel, but in every case it  will not run by optimal and in some cases, the no nitromethane fuel can to have the negative influence to the engine lifetime. In the case, that the recommended content of nitromethane will not specified in the Instructions for engine, it testify about neglection or this description was left by intention or non intention. In every case,  if need to reach the best results of your engine, the compresion ratio must be set for the concrete fuel, so consenquently for concrete content of nitromethane.
►  Unfortunatelly the nitromethane has beside the positive influence on the engine run also some negative property, and it is exclude the economic (higher price of fuel) also the negative influence on metal parts corrosion - mainly for crankshaft and ball bearing. Although the modern fuels contains the corrosion inhibitors what reduced the negative influence of nitromethane very rapidly, it is not reduced totally and so it is neccessary to take a care for all the engines what use the fuel with nitromethane, to be  the  negative influence reduced to minimum as possible.
►  The special chemical preparations named "Afterrun oil", were developed as a support for this care, they contains detergents for carbonised parts of fuel, special corrosion inhibitors and special protective oil. The probleme with corrosion originate mainly iduring the time, when the engine is out off function, whereupon the no burning nitromethane and very hydroscopic metanol (fuel) stay inside the engine.

So if you will need to make something usefull for your engine and need to reduce the negative influnce of nitromethane to minimum, take next steps:

1.  Always stop the engine by the fully fuel clossing (by the main needle or fuel pipe clossing). It concerning mainly the last flight or run in a day, when you can presumpose, that the engine will out of function during some time (few days). By this way all the fuel inside the engine will burn and no  fuel with nitromethane will stay inside.

2. In case, that engine is used very often (with couple od days interuption only), apply few drops of quality afterrun oil to the intake of engine, and by turning transfer this afterrun on all the movable parts.

3. As about four stroke engine, here is very hard to transfer the After ¨run oil into the crankcase throw carburetor, because the crankcase is lubricated by the fuel penetration over piston and sleeve only. Therefore apply the Afterrun by syringe and silicone pipe throw Breather nipple.

4. If longer interruption of engine function (2 weeks and more), it is neccessary rinse the engine by Methanol and than apply the Afterrun oil by the way ushered in the previous points.

5. At the very long pause in engine function (cca 1 month or more) and mainly fter the flyin and driving season, it is recommended to remove the engine from a mosdel, carefully clean it and rinse by Methanol (usually with the disasembling rear crankcase cover) and than apply the Afterrun into whole engine. Disasembled part place to their original positions, slightly apply the engine on its surface and seal off the engine to the plastic bag. With advantage you can insert a small quantity of special hydroscopic stuff (Silikagel) in the bag, the air humidity will be absorbed by this way.

By this way, the negative influence of nitromethane will be reduced to minimum and lifetime of your engine  prolonged to maximum, whereupon all the positive qualities what the nitromethane use offer to you, will stay.

Yours Caliber Team
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