I bought a new Omega caliber 8900 a month ago. However, even though it gained +2 seconds a day when I received it, at the end of one month I'm seeing it gain +5 seconds a day. Is that normal?

 

I noticed on mine that resting it in different positions gives different results. At first no matter if it sat flat, or on the helium escape valve on it’s side, it would gain +2 secs, sometimes +3. After 2 months and letting it sit on the crown overnight, it has been staying at 0 to +0.5 seconds lately.

 

And that's at the normal position?

 

The accuracy of a watch depends of several factors, the position and the tempeature being the most obvious ones. That is why the Chronometer and Master Chronometer tests are done at different positions and temp. Master Chronometer also include a test with magnetic fields.

+5s/d is still within Master Chronometer range (0/+5s), nothing to worry about.
What you can try to bring it back closer to 0s/d is to do the same than @gpstar : test different positions when you let it sit during the night. Flat, on the crown, on the side... Possibly you'll find a position where it gains less time.

 

After testing different positions like @Lurk41 said, I found that when I wear the watch all day, then when I go to bed, if I leave it sitting on the crown, it seems to bring it back closer to 0s/d, thus I haven't had a need to hack the seconds at all lately. I tried resting it overnight laying flat down, or in the original box, on the helium escape valve side (Planet Ocean), etc etc and it would always speed up a little bit by the time I checked it in the morning.

 

Hey guys, thanks for all your input.

As far as I can see, recent omega movements have a tendency of being more accurate at the crown down position. I tried it and now my watch gains 1 second a day.

 

Results from my Omega 8900 the past six days (Resting at night) :



Day 1 : Crown Down = 11:31 PM = +16
= 8:58 AM = +16.5 --> Variation = +0.5


Day 2 : Crown Up = 11:25 PM = +17.5
= 8:24 AM = +19 --> Variation = +1.5


Day 3 : Dial Down = 11:30 PM = +19.5
= 9:19 AM = +22 --> Variation = +2.5


Day 4 : Dial Up = 11:31 PM = +22.5
= 8:42 AM = +24.5 --> Variation = +2.0


Day 5 : 12 Down = 11:39 PM = +24.5
= 07:33 AM = +26.5 --> Variation = +2.0


Day 6 : 12 Up = 11:22 PM = +27
= 07:47 AM +28.5 --> Variation = +1.5

 

tend to be slightly slower in that position.

 

Yeah, I've been getting similar results.

 

I always rest my watch crown down. Keeps the watch as accurate as possible.

 

Also keep in mind that higher temps get the movement going faster while cooler temps get it running slower. I have noticed this on both my 8800 and 8900.

 

How much of a deviation would you say that is?

 

Close to 1 second.

 

Mine is around +5 at the end of a week when worn regularly. I'm very happy with that, although my Pelagos and IWC Spitfire are even better, with the eerily accurate Pelagos gaining less than 1s in a week. Compared to some of the pieces I've owned over the years, I have no complaints about this movement. It's been very robust, accurate, sets precisely and has served me well over the years I've owned it. And the watch that houses it ain't no slouch either.