LONDON, England - the Williams F1 team will switch from Renault to Mercedes engines from 2014 when the V6 units are introduced.The announcement of a long-term partnership means the engines will power four of the 11 teams during the 2014 season before McLaren enter sa new partnership with Honda from 2015.Mercedes also supplies its own works team, winner at the 2013 Monaco GP, thanks to Germany's Nico Rosberg, and Force India.FULL HOUSERenault will have at least three teams for the 2014 season, with Red Bull and Toro Rosso already signed up and Caterham also committed to the French manufacturer. It also currently supplies title contenders Lotus.F1 is ditching the current 2.4-litre V8 engines at the end of the 2013 season in one of the biggest shake-ups of the rules in decades. From 2014, cars will be powered by a 1.6-litre V6 with turbocharger and energy recovery systems.Williams said it would continue to manufacture its own transmission.Team principal and founder Frank Williams said: "Mercedes-Benz has been one of the sport's most successful engine suppliers and, we believe, wiill have an extremely competitive engine."Mercedes motorsport head Toto Wolff is also a Williams shareholder, although he has said he will sell the stake, and his wife Susie is the team's development driver. He said: "The proud heritage of Williams and the company's commitment to technological excellence make it a perfect long-term partner for Mercedes-Benz under the new engine regulations. "It's a win-win situation for HPP and Williams which will ensure HPP (Mercedes high performance powertrains) is able to supply at least three teams on a long-term basis under the new regulations and could open interesting new perspectives for technology transfer."Mercedes will be Williams' sixth change of engine partner in a decade. This winner of nine Constructors' titles used BMW engines from 2000-05, Cosworth in 2006, Toyota from 2007-09, returned to Cosworth for 2010-11 and then switched to Renault in 2012.PRICEY ENGINESThe new engines are expected to be more than double the current R116.7-million cost of the V8 with media reports suggesting the Renault units will be more expensive than those made by Mercedes and Ferrari.Renault said in a separate statement that supplying five teams "will not make sense economically or be ideal for our resources". "Three, perhaps four, teams is the ideal for us so the departure of Williams normalises the situation and makes things much clearer from our side. We will announce the next team within a matter of days and then confirm the final stage before the end of June." Stay with Wheels24 for the 2013 Formula 1 season – fresh reports every day.