Internal combustion engines in line (regardless of whether the work in four-stroke engines and two-stroke engines Otto cycle engines, diesel and Lenoir) are, in general, the most used. Their problem of balancing is extremely important for their operation is correct. There are two possible types of balancing: Static and dynamic balance. The total static to make sure that the sum of the forces of inertia of a mechanism to be zero. There are also a static balance partial. Dynamic balance means to cancel all the moments (load) inertia of the mechanism. A way of the design of an engine in a straight line is that the difference between the crank 180 [°] or 120 [°]. A different type of construction of the engine is the engine with the cylinders in the opposite line, called cylinder sportsmen. In this type of engine (regardless of their position, which is most often vertical) for engines with two cylinders, one has a static balance total and an imbalance in the dynamic. Similar to the model of the earth concentrated in rotation movement are resolved and load balancing shafts rotating parts. An important way to reduce losses of heat engines is how to achieve a better balance. The methods may be used in equal measure and on engines with external combustion, type Stirling or Watt.