A fluid flow engine comprises: a turbine housing including at least one supply channel for supplying a driving fluid; at least one turbine rotor rotatably supported in the turbine housing about an axis of rotation; and a guiding grid of variable turbine geometry radially outside and surrounding the turbine rotor. The guiding grid comprises a nozzle ring forming one end limitation of a vane space and a plurality of guiding vanes each being pivoted about a pivoting axis and being supported by the nozzle ring so as to supply an adjustable amount of fluid from the supply channel to the turbine rotor. At least one spacer is connected to the nozzle ring for securing an axial distance for enabling the vanes to wove freely. The spacer includes at least one bolt or pin tat penetrates into the nozzle ring. This bolt or pin forms itself the spacer by inserting one end of it between the nozzle ring and a part in the turbine housing, while it is fixed to the axial distance of the vane space at the other end by a connection material which may be applied in molten condition, but is then temperature resistant.