Williams handicapped by pre-race engine problem.

Nick Heidfeld and Mark Webber will both be handicapped by a BMW engine problem discovered prior to the Spanish Grand Prix, with the German having to take a ten-place grid penalty for an engine change before the track action even gets underway this weekend.

Team-mate Webber will miss all of Friday's practice sessions, while fresh engines are flown out from BMW's base in Munich.

Heidfeld's engine had already run the San Marino GP and, under this season's rules that demand engines last for two complete meetings, was due to be used again this weekend. However, the BMW engineers discovered a defective exhaust valve when inspecting the engine in Barcelona on Thursday, and will make a precautionary change, penalising Heidfeld ten places over his qualifying position.

Webber was due to start on Friday with a new engine of similar specification, but the Williams team has decided to wait for two new engines of a different spec to arrive from Munich. However, so late was the discovery of the problem, that the replacements will not arrive until Saturday. If Webber doesn't run on Friday, and starts on Saturday with the new engine, he will face no extra penalty.

"The faulty exhaust valve could cause retirement in the race so we have therefore decided not to take that risk," BMW Motorsport director Mario Theissen explained, "At present, two engines of a new specification are being assembled in Munich. We will bring them to Barcelona and install them in the cars prior to the third free practice on Saturday."

Because Heidfeld will be penalised regardless of whether he changes engines now or overnight tonight, he will run throughout Friday's two practice sessions, and conduct the team's tyre and set-up programmes. And, because he doesn't have to save mileage, the German will be able to do as many laps as he wants, subject to the engine actually lasting....