Led by the head of search, Andrea Brown, the four new recruits will join Altogether, Engine's digital arm, and take the group's overall team of search specialists to 15.
Brown is joined at Engine by her former i-level colleagues Nick Smith, who becomes Altogether's head of paid search, Celine Mc- Elwee, the head of business development, and Francesca Gioia, the search project manager.
The team's arrival at Altogether follows a deal last month that saw Engine acquire i-level's social media unit Jam, which is headed by Alex Miller.
I-level went into liquidation last month after its preferred creditor and majority shareholder, ECI, applied for the agency to be placed into administration following the loss of its £40 million COI account to Group M.
Toby Gunton, the managing director of Altogether, said: "Search and affiliate marketing have always been an important part of our business and these appointments will help us to develop it even further."