The Combustion Engine is the third tier of Engines. It uses Iron instead of Wood or Cobblestone, making it the most expensive and powerful engine. It runs the fastest and outputs the most MJ per stroke. It needs a redstone current to function. It draws full stacks when used on a Wooden Pipe. It moves a Quarry without delays between each action. The inner tanks can store up to 16 buckets of a single type of liquid (water, lava, oil, fuel). When using with conductive pipes, a Wooden Conductive Pipe must be connected to the output side (front) of the engine for the pipe to accept energy. After the first wooden conductive pipe, any other Conductive Pipe can be used.