Formula 1's three engine manufacturers for 2014 are hard at work on their new turbo V6 designs, Germany's Auto Motor und Sport reported.The publication said Craig Pollock's new venture Pure is no longer operating, while it is common knowledge in the F1 paddock that HRT and Marussia supplier Cosworth is unlikely to still be on the grid for the radical new rules.'IN LINE WITH PLANNING'That leaves just Mercedes, Ferrari and Renault, with Auto Motor und Sport saying the manufacturers are now "in phase two" of the development process for 2014.It means they are no longer working only with mere prototypes.Renault Sport's Rob White said recently: "We have now run a V6 and the programme is more or less in line with our planning."Our intent is to be 'race intent' in the course of 2013."Toto Wolff, a Williams shareholder and the Grove team's new executive director, told motorline.cc the British squad will "definitely" still be powered by Renault's existing V8 engine next year.And then into the V6 rules and beyond?"That is what we would wish," Wolff said. "Renault has decided to remain in F1 for the long term and talks (between Williams and Renault) are in progress," he added.