  It is shown that aspects of the extended thermodynamic properties of the
Taub-Bolt-AdS spacetime in four dimensions are similar to those of the
Schwarzschild-AdS black hole. In a high temperature expansion, the equations of
state begin to deviate only at next-to-subleading orders. By analogy with what
has been done for black holes, Taub-Bolt's thermodynamic equations are used to
define holographic heat engines, the first examples of gravitational heat
engines defined using a spacetime that is not a black hole. As a further
comparison, the Taub-Bolt engine efficiency is computed for two special kinds
of engine cycle and compared to the results for analogous Schwarzschild black
hole engine cycles.
