This engine has six double-ended pistons working in six cylinders, making it equivalent to a twelve-piston engine. All 12 combustion chambers are fired in a single revolution of the drive shaft. The sinusoidal cam can be seen, together with four of the six pistons and two empty cylinders. the thickness of the cam (and it is everywhere very substantial) varies, appearing thinner where it is at a more oblique angle. The reason for this is that it runs between two rollers, in each piston, that are at a fixed spacing.

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this shows dyna cam engine on the test bed.