I am posting as a postulation for an idea for an engine. I make NO CLAIMS that it works. But in theory it looks like it could work.
Here's an image of what the engine would look like:


The premise behind the engine is that the green pieces in the picture are clamps that hold specific types of magnets with the poles being at the long end of the magnets.

A movie of how the engine works based off an earlier version can be found here:

The magnetic pressure comparrisons between direct contact to a magnet verses indirect contact can be found on this movie:

The last movie shows that the magnet shows less pressure when coming at the second magnet at an angle which is what the piece with the clamp does. This means hypothetically that all you need is that amount of pressure in the spring to cause the piece to come into line with the second magnet which then pushes the second magnet located on the green piece connected to the arm to move forward. If anyone has some time on their hands and knowledge of mechanical engineering and have access to machines. I would love to see someone put this together to see if it's more then just theory.