Please School me on the El Primero Chronograph Movement

Hello All,

I tend to spend my time here in OF in the UG section. That said, I am trying to learn a bit about the Zenith Chronos.

More specifically, regarding the El Primero Chronograph movement -- is there more than one version? I had thought there was a 386 then later a 3019 that evolved into the 400 (which I believe is what Rolex modified for the 16520 ref Daytona), but then I came across this 4002 on eBay

https://www.ebay.com/itm/283202523760?ul_noapp=true

So yes I'm a noob as far as the Zenith El Primero chrono movement... but perhaps someone can help school me?

Thanks!!

Here is a link to what is certainly one of the best online resource on the ELP movement. It is in Italian but you should be able to feed it into a translator if you aren't able to read it.

https://orologi.forumfree.it/?t=31321982

Thank you for this!!

Vi prometto che ne farò una traduzione in inglese che posterò sul vostro forum.😀

I promise you that I will make a translation in English that I will post on your forum.