“No nasty surprises” designing Mercedes installation for McLaren MCL35M

In four races’ time, McLaren will make its third change of power unit supplier since the V6 hybrid turbo power units were introduced to F1 six years ago.

Its technical director James Key, who joined the team last year, is well-placed to oversee the change. He already has experience of switching between three different power unit suppliers while at Toro Rosso.

Speaking to RaceFans in an exclusive interview, Key says McLaren are “fully up to speed” with planning the integration of the 2021 Mercedes power unit.

While this will be McLaren’s third change of engine suppliers in seven years, they were loyal to Mercedes for the previous two decades, and were their works F1 operation for much of that time. “It seems to have almost picked up from where it left off,” says Key. “I know we’re not a works operation, but certainly a very close technical and personal link in some cases.

“They’ve shared all the information we need very quickly. They’ve been open to questions, suggestions and ideas which was within the scope of the agreement to help us out.”

McLaren face a particularly tricky challenge for next season owing to the disruption caused by the Covid-19 pandemic. In their original plan, the switch from Renault to Mercedes power was going to coincide with sweeping new technical regulations coming into force for the 2021 F1 season. However those rules have been postponed by 12 months as a cost-saving measure.

Teams have therefore agreed to largely carry over this year’s chassis to next year. They will be permitted to make a limited number of changes, which are governed by a system of ‘tokens’ covering different areas of the car.

McLaren, the only team switching power unit suppliers for next year, will have to expend all their tokens on making the necessary changes to accommodate the Mercedes. One top of that, they lost several weeks’ work on their 2021 project when their factory was closed as a result of the lockdown.

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“[Mercedes] know that we are under pressure and under a short time period as well with the inability to work on it earlier this year in a big way,” says Key. “So it’s started off very well. We’ve been doing some R&D testing with them at their facilities to make sure that our systems are installed in a way that works for both. That seems to be going okay and we’re fully on top of the programme in that respect.”

Key says the design work around changing the MCL35 to accepted a Mercedes instead of a Renault has been “pretty normal, actually, in terms of going from one engine to another.”

“I’ve kind of become familiar with how this transition works,” he says. “And it’s pretty similar to the sorts of work that you have to do from one power unit to the next.

“There are some fundamental architectural differences between the way power…