LONDON, Dec 28 (Reuters) - West Ham United are trying to raise 80 million pounds ($124.4 million) to clear some of their debt by selling 20 percent of the club, co-owner David Sullivan told the Sunday Telegraph.

Sullivan said West Ham would be worth 400 million pounds when they move to London's Olympic Stadium in 2016.

"We've no desire to give up the whole club but we're still 110 million pounds in debt -- albeit now 55 million pounds of that is to ourselves," Sullivan said.

"So the third-party debt has been halved but only because we put the money in."

Sullivan bought West Ham with co-chairman David Gold in 2010 when the club was valued at 105 million pounds.

"We lost 30 million when we went down (to the Championship in 2011) and we made 10 million on paper last year," Sullivan said.

"I'd love someone to come in and pay 20 percent and the money would not go to us, it would go to the club."

The move to the Olympic Stadium should cover most of the debt.

"But if it doesn't happen we'll dig into our pockets and keep the club afloat," Sullivan added.

West Ham are riding high in fifth place in the Premier League and Sullivan admitted that manager Sam Allardyce could leave Upton Park at the end of the season when his contract expires.

"I must say if come April we are where we are now, which is extremely unlikely but is possible, we'd probably sit down a month early and say, 'Look Sam, do you want to stay or do you want to go?'. Sam may decide he wants to go out a winner."

West Ham brought in nine players before this season, including strikers Enner Valencia and Diafra Sakho, and midfielder Alex Song.

Sakho, who has scored seven league goals, was signed on the recommendation of West Ham vice-chairman Karren Brady's brother and Sullivan said Allardyce had been against the move. ($1 = 0.6431 pounds) (Reporting by Ed Osmond, editing by Alan Baldwin)