An example rotary actuator includes a cam that is to be coupled to a valve. The cam is rotatable about an axis. The example rotary actuator also includes a linear actuator having a stem movable along a path offset from and perpendicular to the axis and a chain having a first end and a second end opposite the first end. The first end of the chain is coupled to the stem and the second end of the chain coupled to the cam. The chain is disposed around at least a portion of an outer edge of the cam, and movement of the stem along the path rotates the cam about the axis.