Ferrari delays use of new engine

The team has been forced to postpone the debut of the new lightweight 048B unit after it failed twice during a Magny-Cours test last week.

A team spokesman said the Maranello-based marque would still use the engine for qualifying.

'We know where the problem is,' he said, 'and if after we change it we can get through two or three days of testing at Silverstone we might race it at the British GP.

'But at the moment the reliability is no more than 50 per cent.'

The evolution of the team's standard V10 is lighter and carries its weight lower to enhance the car's centre of gravity. It was used for the first time during qualifying in Canada.

Schumacher encountered the first failure just 40 laps into the first day of running last week at the Magny-Cours test.

The unit was replaced the following day and the German completed a further 60 laps before stopping after sensing the same problem.

Schumacher's team-mate Eddie Irvine ran over 200 trouble-free laps with the standard engine, setting the quickest time.