Aston-Martin has been using Mercedes-AMG V-8 engines for five years now but the days of the 4.0-liter twin-turbocharged unit seem to be numbered as the British company is developing a new straight-six of its own for use in future models.

Aston-Martin models currently come with one of two engines: the DB11 and the new Vantage are fitted with the 4.0-liter, twin-turbocharged, V-8 of Mercedes-AMG origin while the DBS Superleggera is equipped with an old-school 5.2-liter V-12. The new straight-six engine could be derived from the beefy V-12 according to Autocar magazine although key Aston-Martin figures pointed out that the partnership with Mercedes could continue in one way or another as Aston-Martin gears up on its hybridization dreams.

Soon, you'll see straight-6-powered Aston-Martins again

The rumors surrounding Aston-Martin's future 6-cylinder engine have been brewing for months, helped in no small part by somewhat confusing statements made by key figures within the Gaydon-based automaker. Now, there's news that the unit could be an altogether in-house project by Aston-Martin, with no outside assistance, and with the company's mythical V-12 as a starting point.

According to Autocar, getting engines from Mercedes-AMG was never meant to last for too long, just enough so that Aston could regroup and start work on an engine of their own. While details on the engine are scarce, it's understood that it will use knowledge gained from the Rapide E program although it might not be a full-fledged plug-in hybrid drivetrain as the technology is not "premium enough" according to Aston-Martin.

To refresh everyone's memory, the Rapide E is the electric version of Aston-Martin's 4-door coupe luxury sports sedan which, its latest evolution, should produce around 605 horsepower, some 738 pound-feet of torque and sprint to 60 mph in about 4 seconds. The drivetrain that was designed by Williams Advanced Engineering features two electric motors at the back and allows fast charging through the upcoming 350kWh DC chargers.

So, full hybridization is a while away but the inline-six will be assisted by some sort of hybrid system. Aston Martin's chief engineer Matt Becker commented earlier this year about the 3.0-liter six-cylinder that sits under the hood of the Mercedes-AMG CLS53 saying that it's "a very impressive engine". The engine, with its electric turbocharger, produces 430 horsepower and 383 pound-feet of torque thanks also to a tiny 48-volt hybrid system. Becker more recently returned to claim that his statement about Merc's 6-cylinder was misunderstood and that what he meant was that " might have to one day look at downsizing engines."

Auto Blog points out that the British sports car manufacturer has already been working on a V-6 engine for the Valhalla which means that, if Autocar is to be believed, they're now working on two 6-cylinder engines. Most likely, at least one of these units will be nestled under the hood of the company's first crossover SUV that's coming next year, the DBX.

We know that the deal with Mercedes is set to last for a few more years still so expect a few more twists of this tale to come. After all, Marek Reichman, Aston's Chief Creative Officer, told Motoring that the 6-cylinder for the DBX could be of Mercedes origin and that comes in direct conflict with Autocar's claims. All we can do at times like these when we're faced with conflicting reports is to wait and see. The DBX isn't in the showrooms yet, neither is the Valhalla, and we have no official position from Mercedes-AMG on the matter, either.

In any case, the upcoming 6-cylinder engine(s) would be the first since the supercharged inline-6 that powered the Tom Walkinshaw Racing-developed DB7. That model sported a 336 horsepower and 361 pound-feet of torque that was only available Stateside for two model years: 1997 and 1998. Thereafter, the American market only got the V12 Vantage version.

Autocar0}

Read our full speculative review on the 2020 Aston Martin DBX.

Read our full review on the 2015 Aston-Martin DBX Concept

Everything we know about the DBX

Aston Martin Patents "Valhalla" Name, Could Be a Tip of The Hat To New Supercar