zOwie Omega Discussion Forum

Hi Ken,

The cal. 1164, which is used in the SMPC is based on a Valjoux 7750.

It is a twenty-five jewel movement, 28,800 bph, and is very nicely finished, when compared to other ETA Valjoux 7750s.

The mainplate of the movement is perlage decorated, and the bridges and rotor are cotes Geneves decorated, and beveled.

Screw holes are chamfered, and screw heads polished, and the whole thing is rhodium plated with a very shiny and white finish.

Many people look down on the 7750, in comparison to other chronograph movements, primarily because of the use in it of stamped metal parts, as well as plastic ones in certain places, but watchmakers have attested to the functional advantages to some of these developments, and to the over-all excellent performance, reliability, and ease of obtaining replacement parts and servicing of the movement.

The reason it is not specified properly on a lot of sites is partly the fault of Omega itself, since the production of the SMPC began prior to the upgrade at ETA of the 7750 from 17 to 25 jewels, and this seems to be the only difference in the 1165 and 1154.

Even in recent brochures and watch reference catalogs and magazines, both Omega's own and others, the 1154 is listed as the movement used in the SMPC, though this is no longer the case.

One question I have not been able to answer is why the change in jewel number occurred at ETA in the first place? What substantive difference does it make to the movement, and why is the same cal # used.

Regards,

Mus.