Be Quick! The Rolex Daytona Cosmograph ref. 16520

The Rolex Daytona’s first step towards true world domination can be traced back to one reference. While the brand’s only chronograph had been hovering on the fringes for a quarter of a century, the ignored underdog and a perpetual disappointment in the Rolex stable, it wasn’t until 1988 that its rags to riches story really began.

It was the all steel ref. 16520 that brought the long-awaited automatic movement to the range, with every model subsequent to that containing one of several tinkered-with self-winding Valjoux calibers.

Even when the Daytona was first launched back in 1963, having to manually wind your watch was a concept out of the dark ages. The fact that a supposed high performance timepiece, aimed at the technologically advanced world of motorsport, would grind to a halt should you forget was an anathema to potential customers, and models which today sell at auction for prices that more closely resemble phone numbers, lingered on dealer’s shelves for years at a time.

Come the heady 80s however, and things started to change—and change big. Rolex were on the hunt for a self-winding chronograph movement, and they didn’t have to look far. A relative stone’s throw from their Geneva compound, legendary watchmaker Zenith was just starting to find its feet again following the mauling it had suffered at the hands of the 70s quartz crisis.

Before they were compelled to shut down production, they had been engaged in a fierce battle with a rival consortium of watchmakers to construct the first mechanical automatic stopwatch caliber. Their competition, formed from giants such as Breitling, Hamilton and Heuer had created the Caliber 11; six months later, Zenith, and their partners Movado, brought out the El Primero.

The El Primero and the Cosmograph

Forced to batten down the hatches to survive the onslaught of cheap, disposable electronic watches from Japan and elsewhere, the El Primero had gone into hibernation in 1972. There it stayed while the world recovered from its love affair with quartz and started to yearn again for the sort of horologic artistry that could only come from Switzerland.

Rolex Mens Daytona Cosmograph 16520

With Rolex beating down its door, Zenith dusted off the El Primero and started a fruitful partnership with their allies across the Alps that would continue for another 12 years.

However, this being Rolex, there was still a significant amount of work to do on a caliber generally acknowledged to be the best of its type in the world at that time.

Arriving as the El Primero, the mechanism would eventually leave as the Cal. 4030. In between, the engineering boffins in Rolex’s deep underground lair subjected Zenith’s movement to more than 200 separate modifications, swapping or discarding around half its original components.

Among the more noteworthy revisions were the removal of the date function and the fitting of a new escapement with a larger, free sprung Glucydur balance wheel, regulated by Rolex’s own Microstella screw system.

Gone also was the El Primero’s flat hairspring to be replaced with a Breguet overcoil, and the frenetic 36,000vph balance speed was dropped to a more stately 28,800vph—in keeping with the rest of the brand’s present-day range. It gave the signature sweep to the seconds hand that is a Rolex trademark, as well as allowing for a less frequent servicing schedule.

The New Generation Daytona

The ref. 16520 then marked the start of the Daytona’s journey to the uppermost echelons. When it launched in 1988 the reaction was immediate, with demand so intense there was no way for supply to keep up. Rolex’s reliance on a foreign-sourced engine slowed production down to such an extent that waiting lists started stretching off into years, with dealers cannily stockpiling watches for their favorite customers, or selling them for up to twice their official retail price to impatient queue jumpers.

Its arrival couldn’t have come at a better time. The relatively new phenomenon of watch collecting was reaching fever pitch, and with the release of a new Daytona and the withdrawal of the old, interest in both models went through the roof.

The ref. 16520, becoming better known as the Zenith Daytona, brought with it some aesthetic changes from its predecessor, along with the upgrade in power plant. The original 37mm case bulged to a more contemporary 40mm, and the dial was now given a glossy, lacquered finish rather than the previous matte or metallic.

Those iconic sub dials received a narrow enclosing outer track in an opposing color, the hour markers were now in an applied metal and filled with lume, and for the first time, it was all protected by a scratch-resistant sapphire crystal.

By themselves, relatively superficial changes, but added together and combined with the convenience of the new mechanism, and the ref. 16520 was a spectacular success.

The Variations

As anyone with a nodding acquaintance of the brand knows, Rolex seemingly cannot resist toying with their designs once they have been released out into the wild. The Zenith Daytona is no different and there have been five different versions identified. Only ever released with black or white dials, their comparative rarity has a huge effect on their price on the vintage market.

Marks I and II, for example, feature what’s called the ‘floating’ dial, where the ‘Cosmograph’ tag is separated from the rest of the text above. Later models moved it to its more usual position directly under the ‘’Superlative Chronometer Officially Certified’ lines.

Rolex Mens Daytona Cosmograph 16520 Zenith Movement

The first three versions had an inverted ‘6’ on the 12-hour sub dial, as well as having three dashes in between the markers on the 30-minute counter. More recent examples corrected the ‘6’ and added a fourth dash.

And the final addition to the range, released around 1998, switched from Tritium to Superluminova for its lume, and so lost the tiny letter ‘T’ before and after the ‘Swiss Made’ text below the 6 o’clock position.

All minute amendments, and there are also a number of subsets of each version with ultra rare variations released for just a few short months, such as the porcelain dial with its unique white paint finish.

But perhaps the most interesting are the Mark IV Daytonas from the early 90s. Known as the Patrizzi dials, they are named after Osvaldo Patrizzi, the then chairman of auction house Antiquorum. In 2005, Patrizzi noticed the sub dial’s outer ring on the black dialed versions of the ref. 16520 Daytona was starting to discolor.

As it turned out, the organic varnish Rolex had been using on that portion of the dial was oxidizing, turning the once silver outline a light brown. Even better, the process was gradual and unique to each watch, with no two looking quite the same—which is just fodder to the world’s collectors.

Today, a Patrizzi dial can add a good 25% to the price of a standard ref. 16520.

Buying a Zenith Daytona

There are very few more attractive investment purchases right now on the vintage watch market than the Zenith Daytona.

Released in a range of materials over its 12 year run; yellow gold (ref. 16528), Rolesor (ref. 16523), gold with a leather strap (ref. 16518) and white gold on leather (ref. 16519), it is and has always been the utilitarian steel versions that command the most attention and highest prices.

The lack of precious metals means the ref. 16520 was the most affordable when first brought out, and that is the reason for their popularity and resulting scarcity. Just as it is with the latest Daytona, the steel versions are the ones everyone wants.

Housing the very last movement Rolex ever sourced from an outside company, before creating their own in-house replacement, the Cal. 4130, in 2000, the ref. 16520 is a significant piece of the brand’s history, as well as a beautiful example of the world’s favorite chronograph.

It was the model that changed the script for the also-ran Daytona, taking it from a struggling tool watch to an all out statement piece. Today, it is sitting on the cusp of grail watch status, with the particularly rare floating dial or Patrizzi editions being snapped up by forward thinking collectors, who regard them as the next big thing.

The ref. 16520 is also an unbeatable choice for those who prefer to buy their watches just for the appreciation of the watchmaker’s art, rather than as a potential future investment.

As its continuing popularity shows, there is nothing quite like a Daytona. The one piece every fan aspires to, there has never been a better time to acquaint yourself with this legendary watch.