Two weeks before the 2015 season begins, the shape of the grid remains unclear.

And that is not just because the backmarker Manor's planned resurrection in Melbourne is not yet confirmed.

Force India, for instance, has only just got its 2015 car up and running, after months of rumours of near-terminal financial and supplier problems.

"We have had cash-flow issues, there is no question about that," deputy boss Bob Fernley admitted to Sky.

"It's tough for all the independent teams."

Indeed, rumours swirling in the Barcelona paddock this week suggest that only five or six teams can actually be relied upon to definitely make it to Melbourne in two weeks and then stay alive for the whole of the season.

Amid that backdrop, Bernie Ecclestone met recently in London with bosses of the struggling Lotus, Force India and Sauber teams, according to Auto Motor und Sport.

They reportedly warned the F1 supremo that, as a worst case scenario, they might not even be in Melbourne due to a "cash-flow" crisis.

Lotus owner Gerard Lopez explains: "The months of November, December and January are the worst, as during this phase of design and production you spend 43 per cent of your budget with nothing coming in from the outside."

That is precisely what happened to Force India, some of whose crucial suppliers suddenly began to demand upfront payments.

A voice at the Silverstone based team said: "From April we have no problem, as money starts flowing again. Anyway, we will be at the start in Melbourne."

Meanwhile, Speed Week reports that in Barcelona on Saturday, representatives of F1 engine makers Mercedes, Ferrari, Renault and Honda met to discuss 2017.

At the meeting, a return to V8 engines was ruled out, but while proposals to make the sport louder and more powerful were discussed, no decisions were taken.

Gallery: Teams warn Ecclestone of 'cash flow crisis'

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