Few places exemplify the peak of the internal combustion engine better than the Mercedes-AMG factory in Affalterbach, Germany. There, individual workers assemble entire engines by hand, capping each one off with an emblem bearing their signature. The company’s philosophy? “One man, one engine.”

For decades, that philosophy helped build AMG’s brand. The Mercedes subsidiary is known for taking luxury cars and turning them into the German equivalent of muscle cars: fast, loud and a bit brutish. Its hand-built engines were sought after not only by consumers but other companies. A decade ago, it signed a deal with Aston Martin to supply the British marque with its 4.0-liter V8.

Now, that deal is living on borrowed time. On Monday, Aston Martin announced that it was entering into a partnership with Lucid. The upstart automaker would supply electric motors, powertrains and battery systems as Aston Martin transitions its core models to EV powertrains by 2030. Mercedes is out, and its stake in Aston Martin, which could have grown to 20%, is frozen just shy of 10%.

For over a century, automakers used engines to differentiate themselves from the competition. AMG was long known for hand-built, high-output V8s. BMW’s reputation stems in no small part from its silky-smooth inline-6s. Dodge’s muscle-car image was built on the back of the Hemi brand of V8s. Honda made a name with VTEC, GM with the small-block V8 and Audi got weird with inline-5s. There are more, but you get the picture.