The invention concerns a variable timing device for reciprocating engines with, at least two cam shafts (AC1, AC2) comprising, at least an intake valve (A) and at least an exhaust valve (E) actuated by said shafts, and means for shaft angular offset D1, D2). The invention is characterised in that at least a common valve (A) is actuated by hydraulic transmission means (4, 9, 10) adapted to transmit to said valve the movement of at least two cams (A1, A2) belonging to the shafts with distinct cams (AC1, AC2) capable of being offset relative to each other. The invention also concerns engines comprising said timing system and a timing and turbocharging method capable of using said distribution.