Ford's engine plant in Bridgend will have opportunities to bid for new work which could secure threatened jobs, the Welsh secretary has said.
A leaked document showed Ford was projecting a reduction of 1,160 workers by 2021 at the plant.
But Alun Cairns said he was optimistic there would be chances "to bid for new engines along the way".
He met Ford earlier this week to discuss the life cycle of its engines and said discussions would continue.
- As it happened: Ford Bridgend jobs
On Wednesday, Ford shared its five-year outlook with unions in the wake of reductions in planned investment in its new Dragon engine.
It said there were "healthy volumes" of work over the next two to three years but that "identified workload is reduced" beyond that.
But Mr Cairns told BBC Wales: "There are some good engines, some very good skills, and I'm determined to do everything I can in order to make those jobs as sustainable as possible over the long-term.
"There will be opportunities to bid for new engines along the way so long as we can make the plant in Bridgend, the plant in Dagenham and complementary industries as efficient as possible."
He said Nissan's investment in Sunderland since the referendum would boost Wales component companies while he also wanted to help secure jobs at Toyota's engine plant on Deeside, Flintshire.
"This is about making an automotive sector of the highest standard, of the highest quality products in the most efficient way possible," he said.
"I believe as we exit the European Union we can get to the position where these large organisations can drive the agenda and be part of this global Britain."
First Minister Carwyn Jones said on Wednesday the job losses were a "worst case scenario".
Union Unite said it would "use all its might" while the GMB said the outlook, confirmed at a meeting, was a "real kick in the teeth".