In 1972, Omega introduced an automatic Speedmaster using an integrated movement co-developed with Lemania, Cal. 1040. This was updated as Cal. 1045 in 1974, and remained in production through 1988. In that year, Omega introduced a new movement for the Speedmaster Reduced. Cal. 1140 is a modular movement, combining the thin time-only ETA 2890-2 with a chronograph module (DD 2020) from Dubois Depraz.
The movement was updated in 1996 to become Cal. 1141 and updated again the next year with the new ETA 2892-A2 as Cal. 1143. These were mainly cosmetic and modernization updates, with the core movement remaining mostly the same. In 2000, Omega introduced another refresh, Cal. 3220.
Cal. 1140 was mainly used in the Omega Speedmaster Reduced.