The Seiko caliber 6117B is a vintage automatic dual time GMT movement that was found in the recently re-popularized Navigator Timer watches. This caliber was produced between circa 1968-1975. In 1975, Seiko began producing the caliber 6118A which has the same jewel count and Diashock anti-shock protection.
Difference between 6117A and 6117B?
There are two variations of the 6117: A and B. They are basically the same movement, however, the B adds a desirable hacking feature.
mwbuss8 posted this comment about the Seiko 6117 on thewatchsiteforums:
You’re right, parts are tough to source. Be careful with the stem, some sellers out there will advertise as having them for this movement but they lack the feature to rotate the inner bezel. I have the older 6117 6019 world timer. If you have yours serviced and adjusted I’m sure it can be much more accurate than a minute. When I got mine it was in a jar of broken watch parts. The crystal was so bad I could barely read the dial, but by the time I had it out of the jar it was ticking away. over they course of the next 3 days I checked it against an atomic clock and it was only a few seconds off. the 6117 is an AMAZING movement. In regards to movement parts if you ever need them many parts of the entire 6xxx line are shared.