If it's a new (or recent-ish used) it's what Ford currently brand as 'Duratec Ti-VCT', which is the latest generation of 1.6l engine from the Sigma family. The earlier versions of that engine were known as Zetec-SE and are what Caterham used in the smaller engined cars once the K-series finished. Zetec/Zetec-E/Zetec-R are what Ford variously called the Zeta family of engines, some of which do appear in Caterhams when swapped in by owners, usually as an upgrade from a Crossflow. The Sigma family are the 'other way round' so you have to swap over exhaust/inlet sides on a Seven that has had a Crossflow in (or indeed a K-series) to upgrade to a Sigma.