Abstract: A rotary blower (26) includes a torsion damping mechanism for transmitting torque from an input drive (48) to a first timing gear (62), the mechanism including an input hub (52), an output hub (64), and a torsion spring (70) having an input end (72) and an output end (74). The housing (42) defines a chamber (44) containing fluid rotation of the timing gears resulting in an air-oil mist. The input hub and output hub define an axial gap (82) intermediate the input and output ends of the torsion spring. The output hub (64) defines an angled passage (86) having a radially outer end (84) in communication with the axial gap (82), and a radially inner end, whereby rotation generates a flow of the air-oil mist through the angled passage (86) and between the outer cylindrical surface of the hubs and the inside surface (76) of the torsion spring (70).