The most convincing fake Omega Caliber 8605 is a decorated Asian automatic clone built around the real movement's architecture: twin barrels under the rotor, a co-axial-style escapement layout, a 25,200 vph beat and a rotor engraved in Omega's own lettering. That build takes the top spot because it stays believable when the caseback comes off. The alternatives were ranked on four criteria: movement architecture, beat rate and finishing, how the watch reads from the dial side, and how the movement behaves in daily wear. Price was left out of the ranking, since a cheaper movement with the right layout beats an expensive one with the wrong one.

Caliber 8605 in Brief

Caliber 8605 sits in Omega's 8500 family: an automatic, co-axial movement with two barrels, a 25,200 vph (3.5 Hz) beat and about 60 hours of reserve. The Master Chronometer version carries METAS certification and a silicon balance spring. For a replica buyer, the useful part is the silhouette: the twin barrel bridge under the rotor, the co-axial escapement under a jeweled bridge, an engraved rotor with the correct font, and a date at the position the genuine reference uses.

A replica movement will not have METAS certification, and it will not have a silicon hairspring. What a good fake does is copy the visible architecture, because that is what you or a watchmaker sees once the caseback is open.

Option 1: Decorated Asian Automatic Clone (Top Pick)

This is the build that tries to be the movement instead of hiding it. The plates are shaped like the 8500-family layout, the rotor carries Omega-style engraving, and the automatic winding train sits where the genuine one sits. Beat rate runs at 25,200 or 28,800 vph, which gives a sweep on the dial that matches the real watch.

Pros

  • Correct plate architecture and rotor engraving, so the movement photographs the way a genuine 8605 does.
  • Seconds hand sweeps in a continuous arc rather than stepping.
  • Accepts the correct caseback, crown and date window position.
  • Serviceable by any watchmaker who works on Asian automatics.

Cons

  • No METAS certification and no silicon balance spring.
  • Finishing is machine-applied, so perlage and anglage look flatter than the genuine article under magnification.
  • Reserve tends to fall short of the real movement's 60 hours.
  • Timekeeping varies between batches, so regulation on arrival is common.

Use case: daily wear where people see the watch and not the movement. This is the pick for anyone who wants the closest thing to an 8605 on the wrist and may hand the watch to a friend to look at.

Option 2: ETA or Sellita Base With a Decorative Plate

A proven 2824-pattern or Sellita-pattern automatic with a cosmetic plate screwed over the top. The base movement is dependable, the looks are an afterthought.

Pros

  • Reliable base with a long service history.
  • Easy to regulate and repair, with parts that are simple to source.
  • Steady timekeeping, often better than a clone right out of the box.

Cons

  • Wrong architecture: single barrel, no co-axial layout.
  • Rotor engraving is shallow or laser-etched and reads as a costume piece.
  • Hand-winding feel and date jump differ from the genuine movement.
  • Anyone who knows the 8500 family spots it in seconds.

Use case: buyers who care more about reliability and easy repair than visual fidelity, and who will not open the caseback in front of other people.

Option 3: Quartz 8605 Lookalike

Quartz inside, engraved caseback outside. It exists to look right on a wrist at arm's length.

Pros

  • Accurate and free of winding.
  • Thin case profile, low maintenance, no rotor noise.

Cons

  • The ticking seconds hand is an instant tell.
  • No rotor at all, so the watch has to stay closed.
  • Caseback engraving is the only thing selling the movement story.

Use case: photos, costume use, or a gift for someone who will never inspect the movement.

How to Inspect a Fake 8605 Before You Buy

  1. Ask for photos of the movement itself, not just the dial.
  2. Compare the rotor engraving against a genuine 8605 photo. Font weight and cut depth matter more than the words.
  3. Count the bridges under the rotor. The genuine movement shows twin barrels, so one large single bridge is a giveaway.
  4. Watch the seconds hand for a full minute. Quartz ticks once per second; a 3.5 Hz automatic moves in a near-continuous sweep.
  5. Check the date change. It should flip at midnight, not creep across the last hour.
  6. Wind and set it. A gritty crown or a skipping date points to a low-grade base.
  7. Treat any Master Chronometer or antimagnetic claim on a replica as marketing copy, not specification.

Which One Fits Your Use Case

  • Closest visual match, worn often: decorated Asian automatic clone.
  • Long-term ownership and easy servicing: ETA or Sellita base with a plate.
  • Short-term looks on a budget: quartz lookalike.

One last point on expectations. Caliber 8605 is a Master Chronometer movement with a certification trail behind it, and no replica shares that trail. The realistic goal is a watch whose movement looks correct when the caseback opens and behaves like an automatic on the wrist. Judge a fake 8605 on those two things and the choice becomes simple.