A fake Omega Caliber 8605 is not an Omega movement. It is almost always a Chinese automatic chronograph from the ETA 7750 family, built by Seagull, Hangzhou, or another clone maker, then fitted with engraved bridges and a rotor stamped 8605 to imitate the real thing. No replica version has a true Co-Axial escapement, twin series barrels, or an Si14 silicon balance spring.
What is the genuine Omega Caliber 8605?
The real Caliber 8605 is an automatic Co-Axial chronograph with a date, part of Omega's 8500/8600 generation. It runs at 25,200 vibrations per hour (3.5 Hz) with two barrels in series, producing about 60 hours of power reserve. Omega equipped it with an Si14 silicon balance spring and a free-sprung balance, then certified the finished watch as a chronometer.
What movement sits inside a replica labeled 8605?
Nearly all of them use a 7750-derived automatic chronograph, most often a Seagull ST1940 or a similar Chinese copy of the Valjoux 7750. The factory then adds cosmetic plates, engraved markings, and a decorated rotor. The base architecture keeps the standard lever escapement the original never used.
Why the decoration fools buyers
From the caseback, a decorated clone photographs convincingly, and sellers post macro shots that hide the tells. Under a loupe, the engraving is shallow and stamped rather than cut, and the jewel and screw layout does not match Omega's design. The rotor usually spins with a louder, rougher feel than the original.
How do you tell a fake 8605 from a real one?
- Escapement: A genuine 8605 uses a Co-Axial escapement with a three-level pallet fork. A clone uses an ordinary Swiss lever escapement.
- Balance and hairspring: The original has a free-sprung balance with no regulator index and a silicon hairspring that reads grey-black under light. Clones show blued steel or a bright alloy spring.
- Power reserve: Real examples run close to 60 hours. Most clones stop between 38 and 45 hours when left dial up.
- Sub-dial and date behavior: Check that the chronograph counters and the date change match the reference you are buying, not a generic layout.
- Price: A genuine 8605 chronograph sells for thousands of dollars. If the entire watch costs a few hundred, the movement is a copy.
Does a fake 8605 keep good time?
A well-regulated clone can hold within roughly 10 to 20 seconds per day, and occasional examples do better. It will not match chronometer certification, hold amplitude over years, or match the original service interval. Expect a service every three to five years, sometimes sooner.
Can a watchmaker service one?
Yes. Because the base is standard 7750 architecture, any qualified watchmaker can clean, lubricate, and regulate it. Genuine Omega parts will not fit, and authorized service centers will decline the watch. Ask for a 7750 service rather than an Omega service.
Frequently asked questions
Is there a 1:1 clone of the Omega 8605?
No. Replica factories copy the appearance of the movement, not its engineering. The Co-Axial escapement, silicon balance spring, and twin-barrel layout stay out of reach at replica prices.
How much should a replica with a fake 8605 cost?
Premium replicas with a decorated 7750 clone generally sell between $250 and $600, depending on case finishing and bracelet quality. Prices far below that usually point to a lower-grade clone or a quartz substitute.
Do replica 8605 movements include a working date?
Usually yes, since the 7750 base has a date mechanism, but the change can be slower or less crisp than the original. Quick-set behavior varies by factory and batch.
Why do sellers call it Swiss made?
The markings are cosmetic. A movement assembled in China and decorated to look Swiss is not Swiss made, regardless of what the engraving claims.