Mercedes has revealed to encountering "issues" with its power unit for the coming season but is confident of having fixes in place before the campaign begins.
The team is due to reveal its Mercedes-AMG F1 W12 E Performance early next month ahead of pre-season testing that begins in Bahrain on March 12 before the opening grand prix a fortnight later.
With the clock ticking, Mercedes-AMG High Performance Powertrains managing director Hywel Thomas has confirmed his team is facing a race against time.
"In terms of readiness, we’ve got plenty of engines in build at the moment getting ready for the new season," said Thomas.
"We have already got some of them together and we have also got engines running on the dynos right now, doing their durability runs.
"There are also engines for our customers too, which are already with them and either in the back of their chassis and fired up, or in the process of doing so.
"We have got some issues with the power units, we know we have issues but we have plenty of plans in place to fix all of those issues. I’m sure it will all be ready for the first race.“
Mercedes' problems have been compounded by a number of factors, including the short turnaround time since last season that was affected by the Covid-19 pandemic, supplying for an additional customer in McLaren, as well as the fact all power unit manufacturers are only allowed a single performance upgrade during the season.
Thomas added: "The winter is always a challenging time for us, as we prepare for a new season, and this year there have been a few extra additional things thrown at us.
"It’s been the first winter where we’ve had to react to a change to the regulations, which limits the amount of dyno hours we’re able to run.
"This means we have to make every single dyno run count and must make sure that we are entirely productive, to learn about the performance and the reliability of the power unit during each hour.
"Also, it’s the first winter where we have prepared for only one single upgrade for the whole season.
"So, we have to get all of our performance into the first PU that goes to the first race, whereas in previous seasons we have been able to split that up into different packages for each PU that gets introduced.
"With that challenge, we have to get absolutely everything there for the first race and make sure it’s completely reliable.
"Also, there are more races this season and the same number of power units, which means that each individual power unit needs to run across more races. We just have to make sure that we are ready for that and focus even more on reliability.
"We also have the challenge of a pretty short winter, as we didn’t finish racing until the middle of December and now, we’re straight back into it. So, if anything, we’ve had more to do and less time to do it in."
As for taking on McLaren, that recently fired up its power unit in the back of the MCL35M, Thomas said: "The most important thing for us is because we’ll be producing more engines and sending more engines to races, we don’t want to have to freeze the specifications any earlier.
"Because that’s time we couldn’t get back, and we really need to make sure that we are getting every ounce of performance and reliability into the power units.
"So, that gives us the challenge of understanding how we can build the engines, can we be more effective, can we be more productive and we’ve got all the plans in place so we can build those extra 25 per cent without having a huge impact on what we are able to take to the circuit."