This is to answer your question you put on the “Shout Box”. As the name implies, a gas engine means an engine that is working fueled by gas, while the gas turbine is the turbine (rotary engine) that is working due to supplied by gas. You may imagine a gas engine is like a diesel genset widely used, but the it’s using gas, not oil. While the gas turbine, you may imagine a turbine that is installed in a gas fueled power plant. Microturbine is one of the examples.
Anyway, this topic has already been discussed in one of mailing list I joined, Milis Migas Indonesia. You may refer the summary of the discussion here. [Click Here].
Further discussion is welcomed.