F1 leader Hamilton facing engine headache

LONDON, England (CNN) -- The two Formula One world championship contenders, Lewis Hamilton and Felipe Massa, have car concerns ahead of their final-race showdown in Brazil.

Hamilton's McLaren will be running its engine for the second race of two, whereas the Ferrari pair of Massa and Kimi Raikkonen, along with Hamilton's team-mate Heikki Kovalainen, will have new engines for the race.

Massa's worry is the lack of speed he had in China, where he was outpaced by race-winner Hamilton and Raikkonen throughout the weekend, only finishing second after team orders slowed the Finn. Massa trails Hamilton by seven points.

McLaren are conscious of the need to manage Hamilton's one-race old engine, which will give away perhaps a one-tenth of a second per lap to a new motor. Read more about F1 at The Circuit.

"Of course, we are keenly aware that the world championship could be won or lost by a mechanical failure," said McLaren chief executive officer Martin Whitmarsh.

"As a result, we are leaving no stone unturned in our efforts to minimize this possibility. For example, that meant consciously turning down Lewis's engine on the run to the flag in China in order to give him plenty of engine life for Brazil."

McLaren could have given Hamilton a new engine for the last race if they had not played their 'joker' -- the one free engine change each driver has per season -- earlier in the year.

The Englishman would be punished with a 10-place grid drop if his engine was changed before the Sao Paulo race.

But despite Hamilton suffering a reliability glitch during last year's Brazilian Grand Prix that effectively cost him the title, Whitmarsh is confident of being able to push for victory in a race where fifth place would suffice.

He added: "Clearly, we can afford to be more conservative than normal in our approach to Lewis's race, [but] there's no reason why we can't take forward the pace and form we showed in China to achieve a one-two in Brazil.

"We do have a number of minor aerodynamic upgrades in the pipeline that we are evaluating for inclusion on our Brazil-spec car."

Meanwhile Ferrari are looking into where their performance advantage over McLaren, which was clear in the Singapore and Japanese races, went in China.

"We cannot be fighting for the titles in the condition where our car is less competitive, with such a big gap to McLaren," said Ferrari boss Stefano Domenicali, ahead of a race Massa won in 2006 and dominated in 2007 before moving aside for Raikkonen.

"We need to understand why there was this kind of change on the performance side. I don't believe that in one week all the others have made a step which we haven't, so it's something connected to our performance.

"This is why we must work hard because we need to make sure that we do everything in order to have a good car for the last grand prix."