Lewis Hamilton and his Mercedes team have taken a calculated risk in replacing his engine for this weekend’s Turkish Grand Prix. The world champion will receive a 10-place grid penalty from which he is hopeful of coming back to minimise the points he is likely to drop to his title rival, Red Bull’s Max Verstappen. Hamilton is locked in a tightly fought contest with Verstappen and holds a slender lead of two points after 15 rounds. Seven meetings remain, including Istanbul Park, and with Mercedes concerned about the reliability of their current engines they have opted to take their fourth of the season, one more than is allowed by the regulations, triggering the penalty. It puts Hamilton in a potentially treacherous position for the race. Regardless of where he qualifies the world champion will be starting in the midfield and must negotiate the opening laps, particularly the short run in to the 90-degree left-hander of turn one, without incurring any damage, before beginning the task of moving through the field. He remained cautiously optimistic about his chances in the race. “I have a lot of work to do on Sunday so whatever the case I am going to try and focus on how I can get the best out of it,” he said. “I need to be on pole to limit the loss and then of course I need to understand the car to do my best in terms of the long run.” Hamilton does have form in coming back at Istanbul Park. In 2006 while competing in GP2 he recovered from a spin that dropped him to 19th place to claim second. Verstappen took an entire new power unit for the last round in Russia and with the penalties incurred started from last place, but aided by rain late in the race he managed to secure second – a remarkable piece of damage limitation. Mercedes have opted not to replace the other elements that compose the power unit, which would have necessitated starting from the back of the grid. Hamilton still has two fully functioning power units in his pool, meaning he still has two sets of the other elements to draw on. These are the motor generator units, heat and kinetic, the turbo, the control electronics, energy store and exhaust system. Mercedes are confident that their pool of these parts is sufficient to see them to the end of the season, and that replacing them would not offer a performance advantage, so opted only to change the engine. The team principal Toto Wolff noted that their greatest concern was a DNF due to an engine failure. The Mercedes trackside engineering director Andrew Shovlin confirmed in Turkey that it was reliability and a marginal performance improvement from the engine they were looking for. “We’re simulating all the races to the end of the year,” he said. “There’s a balance of the risk of a reliability issue, obviously the thing you definitely don’t want to do is fail during a race and then have to take a penalty anyway, and then there’s the performance element because the power units do lose a bit of a horsepower over their life. It’s better to take 10 places than start at the back.” On Thursday Hamilton had been emphatic that he was not expecting to take a new engine in Turkey but the team have clearly decided that he stands a good chance of making up places at Istanbul Park. He won here last year in wet conditions on a low-grip track to take his seventh title and with rain expected again on Sunday and the circuit now offering more grip, will expect to do well again. However it will be far from straightforward. The Mercedes has struggled to pass the McLaren recently and both their cars are likely to be in front of Hamilton, as will Verstappen’s teammate Sergio Pérez. Mercedes’ risk is therefore twofold. Firstly, in taking only the engine rather than the complete raft of power unit components they might still have to suffer further grid drops at a later date, while Hamilton must negotiate some nerve-wracking opening corners. He will doubtless be as circumspect as always but he will have much more to lose than the drivers charging for places around him when the lights go out. His form in Istanbul certainly looked positive. Hamilton was quickest in first practice, setting a new track record and four-tenths up on Verstappen. In the afternoon session he was once more on top in front of Ferrari’s Charles Leclerc and six-tenths clear of his title rival in fifth, who was suffering from understeer and was unhappy with the balance of his car.