I’m sure most of our readers are as curious as I was to get my hands on an 8500 movement for the first time. I had of course seen one before, but so far, no service had been required. So I went out and bought myself a 1 1/2 year old Planet Ocean with box and papers in order to have a good look.
Before opening it, I do a bit of testing. I get a 67 hour 50 minutes power reserve, and that is impressive. The two barrels are doing their work it seems. In terms of accuracy, I am disappointed, as the watch gains 4 to 5 seconds per day, and not at a constant rate. I expected much better from a 1.5 year old 8500.
The movement is beautifully decorated, and has a balance bridge instead of a balance cock, just like the Rolex 3135.
The Silicon (silicium) balance and hairspring. Great stuff, as it’s a lot more temperature stable, and adds to the accuracy of the movement. At the top, there is a brass screw to adjust the height of the bridge on once side to adjust the end shake of the balance. The Rolex 3135 has that as well, but it can be adjusted on both sides so that the bridge is always parallel to the plate.
Very nice construction with the two barrels. One barrel contains a manual mainspring (I measured 1.17mm x 0.095mm x 340mm), and the right barrel contains an automatic mainspring (I measured 1.49mm x 0.08mm x 400mm). The manual mainspring is weaker than the automatic one, so it will wind fully first, then the automatic spring is wound until it starts slipping in the barrel. A lot better than other long power reserve movements with only one mainspring.
And yes, astonishingly, the movement really did need a service after 1.5 years! The movement is slightly slow, but I can’t get hold of the special tool to adjust the balance. I have ordered it, and I should get it within the next two weeks for a mere £300.
Now the bottom plate comes back together. There is no quick-set date, but the hour hand jumps from hour to hour in the first crown position, so you have to go through 24 hour clicks to change the date by one day. That’s quite normal for movements that have an hour jump function, as that works on the first position, which is otherwise used for the quick-set date.
The date change is anything but snappy. You can see here that the 22 is already going down to make way for the 23, without the date changing over. It’s a very standard ETA type date wheel, and a bit disappointing. The Rolex 3135 date change mechanism is a pure joy to look at, and by far better than this.
Nice looking watch, but very very high – 16.2mm!
So, what do I make of it?
I love the look of it, the decoration, the jeweling, the silicon balance and hairspring, the accuracy (once it’s serviced again), the two barrels and the power reserve (even though I’m not quite sure what I need that for).
I don’t like the slow and cheap date change, the fact that I had already dirt under the barrel and that the movement needed a service after 1.5 years, and the height of the movement. It’s made for chunky watches, but it would have been nice to see this in a more elegant (and less high) case.
The construction is very ETA, and ETA will of course have played a huge part in developing this movement, as it’s a long time since Omega had an in-house movement.
I finally got the tool to adjust the beat rate, it’s an Omega original tool, and I paid £301 for it. Believe it or not, it doesn’t fit properly, and only slides about 1/3 over the adjustment screws. Well done, Omega.
I adjusted the watch last Thursday, and have worn it since. Today is Tuesday, and the watch is exactly 1 second slow, so -1s in 5 days. That’s pretty impressive, and we will see if it continues to perform that well.