Renault is open to McLaren influencing the design of its F1 engine, but says the British team is unlikely to have any impact until the partnership enters its third season.
McLaren has given up works status with Honda to join Renault's customer F1 engine programme until the end of 2020, when the current engine rules cycle concludes.
As a works partner with Honda, McLaren influenced the design and packaging of Honda's troubled F1 engine, sending personnel to Honda's Sakura HQ and even collaborating on the design of certain electrical components of the power unit.
By returning to customer status, McLaren will now have to adjust its chassis around whatever product Renault delivers.
McLaren hopes to influence Renault's engine in a similar way to Honda as their new relationship develops, but Renault F1 boss Cyril Abiteboul told Autosport the deal for 2018 came too late for McLaren to have any immediate say on engine design and packaging.
"It's a bit complex," Abiteboul said. "First and foremost, we developed a complete power unit before working with McLaren.
"So it's not like with Honda, where Honda was dependent upon McLaren - we have the whole parameters of the power unit under our responsibility.
"We will take it step by step. We want to be very pragmatic. Clearly for 2018 and even 2019, it's very late for McLaren to have any influence on the hardware of the engine.
"Having said that, we want to be humble. We accept that we can improve our product, that we have to improve our product, and we will be open to their suggestion.
"It's more on the medium to long-term. We have to accept it's a new relationship, we will have to see how it evolves, but if it's working well, if it's a fruitful and positive relationship, then there is no reason it could not go further than this cycle of regulation.
"But it's not something for before 2020 in my opinion."