Not a one Mike. Zenith's marketing department gave very little signs of life in the late 1960s - early 1970s, and certainly did not get involved in sports sponsorships. It's the norm now, but Jack Heuer pretty much invented the concept, so it shouldn't be surprising that other companies weren't even on the grid back then.

Zenith's advertising pretty much focused on the features of the watch itself, be it the Primero, Defy or other model - precision, durability, first automatic chronograph with date, etc, etc. It was very much in the Zenith advertising tradition. Remember that before 1960 Zenith had no in-house chronograph, and its reputation rested almost entirely on precision. It had an amazing ability to accumulate chronometry prizes at the various observatory competitions, and ended up with nearly twice as many as the nearest competitor, including multi-year sweeps at Neuchatel with the legendary caliber 135.

: I'm curious, did Zenith ever sponsor any racing drivers in the late
: 60's - 70's? Other than accuracy and innovation, I was wondering
: if there was a certain sport or personality associated with the
: original El Primeros?

: Cheers!
: Mike