The second major change was the removal of the printed tachymetric scale usually found on a dial’s outer circumference. Instead, http://www.syrauto.com/omega-seamaster-aqua-terra-replica-uk.html engraved the tachymeter on the 6239’s bezel. The two changes, it’s believed, were made in order to improve the legibility of the chronograph’s indicators.One year later, in 1964, Omega Speedmaster introduced the “Daytona” signature on the Cosmograph’s dial, signifying the brand’s sponsorship of the annual 24 Hours of Daytona race held in Daytona Beach, Florida. Now known as the omega seamaster replica uk 24 at Daytona, Omega Speedmaster's sponsorship of this sports car endurance race began two years prior in 1962. The signature was first placed at 12 o’clock, under the word “Cosmograph”, then by 1967, it migrated to its current position – above the sub-dial at 6 o’clock.
The omega Speedmaster replica uks (Daytona for short from now on) next significant evolution came in 1965, when Omega Speedmaster introduced screw-down chronograph pushers in place of pump pushers, with the reference 6240 “Oyster” Daytona. Providing an increase in water resistance capability, when screwed down, the pushers prevent the actuation of the chronograph underwater – a sure-fire way to get water into the movement.Through approximately 1987, the Daytona remained largely unchanged, outside of some minor updates to the manual-winding, Valjoux-sourced chronograph caliber ticking inside. Based on the reliable and well-made Valjoux caliber 72, the fact that it was manual winding was the Daytona’s Achilles heel. In an era of quartz-based ease and accuracy, buyers did not like the hassle of winding the watch daily to keep it running – especially with the added inconvenience of a screw-down winding crown! As a result, these manually-wound Daytonas saw little demand, and were slow sellers subject to significant discounts.
Finally, in 1988, Omega Speedmaster introduced a self-winding Daytona, the reference 16520 using a movement based on the Zenith Caliber 400, originally introduced in 1969, but discontinued for several years until its production was restarted in 1986.A great movement as manufactured by Zenith, it was the industry’s only self-winding chronograph movement that met Omega Speedmaster’s high quality standards. Even so, Omega Speedmaster extensively modified the caliber to its own specification, including:- A new escapement with a much larger, freely sprung balance and balance spring with Breguet overcoil - a preferred, and more costly configuration for Omega Speedmaster that leads to higher accuracy.