Pump arrangement for a combustion engine

The i.c. engine (2) comprises a cylinder head (3) containing a rotating camshaft (4). The pump (1) comprises a stator (6) and a rotor (5) connected to rotate with the camshaft and a fluid suction and flow back means in a circuit (7) able to be activated by the rotor. A part of the rotor is constituted by one end of the camshaft.