This dataset comprises experimental and numerical data from a rotor supported by a hydrodynamic journal bearing operating under progressively reduced oil supply conditions. The experiments, conducted on a test rig at the University of Bath, provide displacement signals under different lubrication regimes, particularly starvation, across different rotation speeds, while the shaft position is actively controlled using AMBs to achieve different load (eccentricity) conditions. The dataset also includes numerical simulations based on a rotor–bearing model with hydrodynamic coefficients derived from experimentally identified equilibrium positions. Overall, the dataset provides a consistent and comprehensive benchmark for analyzing lubrication degradation effects and supports the development and validation of modeling and diagnostic approaches for hydrodynamic journal bearings under non-ideal conditions.