The X layout engine might be one of the least commercially successful engine layouts in history.

However, it's still in production today in a unique military application.

Opposed-piston engines are unique, interesting designs that have proven themselves throughout history.

With two pistons per cylinder, opposed-piston engines offer higher power in a smaller package.

Triangle shape block, opposed piston, two-stroke, three cranks, the engine that changes the face of diesel.

Check out the 88 plus liter Napier Deltic engine!