Engine Temperature, How Hot and How to tell?
You tune the engine by measuring the engineís temperature, and making the required adjustments to make the temperature correct. There are two ways to measure the engineís temperature:

a) Temperature gauge method: Get the engine up to running temperature, bring the car into the pits and immediately take a temperature reading. Place the temperature gauge directly over the engine, pointed at the glow plug, and take a reading. Itís easier to do if you have a second person to take the readings for you. or you can have the on chassis units that are connected to the head of the car via a lead.

b) Spit method: Get the engine up to running temperature, then pull in as quickly as possible and put some spit on the engineís cylinder head (quickly, so as to not burn your finger). The saliva should just slowly boil off (2 to 3 seconds). It should NOT dance around as if it were on a hot griddle, nor should it lay there and steam. In short, if your spittle will sizzle, it's too hot.

The best method is to get a temperature probe, there are several different types on the market, the kind that mount on the chassis of the car with a lead that connects to the head of the engine to monitor the temperature. Or there are the infra red hand held units that are more precise but far more costly.

If the engine is too rich, the engine temperature will be colder than desired (and vice versa). If the engine is too lean, the engine temperature will be hotter than desired. Go out on the track with the top end rich. If youíve got the mixture set right, there will be heavy smoke from the engine on the straightaway. Run four or five full laps to get the engine up to running temperature before touching the carb. Bring the car in, and take a temperature reading. Start leaning out the top end by turning the adjusting screw only 1/12 turn at a time (picture a clockís 12 even spaces). Take your time doing the adjusting - donít be in a hurry. It may take a while. Your goal will be to get the car to just "punch clean" when you come onto the straightaway, which is what it will do when the mixture is set properly. For 1/8 scale cars, youíll have the correct mixture when the temperature is about 200 degrees. The 1/10 scale cars run a little hotter, maybe around 250 degrees.












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