  We study the impact of entangling measurements on the efficiency of quantum
measurement- based engines. We first show that for engines comprising many
subsystems their efficiency can be enhanced by performing entangling
measurements, as opposed to local measurements over each subsystem. When the
collective measurement produces the same local state for the subsystems as
individual local measurements, the improvement in the efficiency is
proportional to the amount of correlations. Finally, we show that for two level
systems these type of engine can operate at perfect efficiency while yielding a
finite amount of work, in the limit large the number of subsystems.
