Stirling Engine Final

As part of a project I'm developing - inspired heavily by Chris Kuhn's excellent contraint-rigging tutorials - I used this technique to make a Stirling engine. Since the gallery doesn't like animations at the moment, here's a link to a gif of a quick animation: https://drive.google.com/file/d/0B9N5q1GrW8qwbEMzekVpYllMUHc/view The principle is that as the gas in the cylinder over the flame heats up it pushes the piston out; but the wheel also drives a displacer core into the "hot" part of the cyliner, moving the gas into the "cool" part of the cylinder, where the heatsinks cool it down and piston gets sucked in again. I have, however, just noticed that I've set the model up slightly wrong - currently the piston is being pushed out when the gas should be cooling! It'll be a simple fix, but I don't want to render the animation again. Also, this is more or less a proof-of-concept test, so the materials and flame animation are pretty basic, as is the camera path - still, pretty pleased with the result.