Ford currently produces Fiesta engines, along with engines for various Jaguar Land Rover models, at its Bridgend plant in South Wales. It also makes diesel engines in its Dagenham factory in Essex.
Concerns over both plants have been growing recently, as Jaguar plans to build its own engines elsewhere, and demand for diesel cars plunges.
The Unite Union believes that the solution to preserve both plants is a comprehensive switch to electric car technology manufacturing, especially battery technology.
On Wednesday, the union will unveil a report detailing proposed plans to protect over 800,000 jobs in the UK automotive industry.