Australia is home to the only surviving 1914 Delage Type-S grand prix car in the world, and thanks to a world-first feat of technology this much-loved centurion is still on the road.

In 2014, when the engine block cracked and water pumped out of the exhaust system, the Delage ground to a halt and was consigned to a mechanic's workshop in Castlemaine, 130 kilometres north-east of Melbourne.

The cloned engine successfully installed by Grant Cowie. ( ABC Radio Melbourne: Fiona Pepper )

With no replacement parts or original drawings to go by, and with few people having the traditional manufacturing skills, pre-war motorcar engineer Grant Cowie looked for alternative ways of rebuilding the complicated 16-valve engine.

"I knew that to use the traditional method, which involves a wooden pattern, would be prohibitively expensive and with such a complicated casting it was possible it would take several attempts to get it correct," Mr Cowie said.

The history of the Delage In 1914 just three Delage Type-S cars were made for a premier race in Lyon, France

In 1914 just three Delage Type-S cars were made for a premier race in Lyon, France World War I began a month after the race and racing in Europe came to a halt

World War I began a month after the race and racing in Europe came to a halt The Delage Type-S cars were sold to the US, then in the 1920s one of them was brought to Australia to race

The Delage Type-S cars were sold to the US, then in the 1920s one of them was brought to Australia to race The car was driven by some of Australia's earliest race car drivers and was owned by motor racing legend Lex Davison

He decided that using digital technology to clone the original block would be the most accurate, efficient and non-destructive method to get the car back up and running.

The trouble was, a repair this complex had never been attempted before.

Recreating the engine block

Using powerful lasers, the engine block was scanned inside and out, saving thousands of hours of pattern making, with months of work done in a few days.

The scan data was then used to digitally repair the cracked engine on a computer before a sand mould was created using a 3D printer.

The original engine block is scanned, a 3D-printed sand mould is created, and the new engine block is cast. ( Supplied: Philip Guilfoyle )

A local iron foundry cast the engine using the 3D-printed mould, before it was finished with traditional manual machining.

After the engine was installed, there was an enormous sense of relief when the Delage turned over successfully.

"It's one thing to finish machining it, then you've got to put it all together," Mr Cowie said.

"And just the relief when it first started — and it's been great since the moment we started it."

Grant Cowie, the pre-war motorcar engineer who cloned and installed the new engine block. ( ABC Radio Melbourne: Fiona Pepper )

While many modern car parts are 3D printed, project manager Philip Guilfoyle said a repair of this scale was unique.

"To my understanding this hasn't been done before in car restoration in the world," he said.

Car owner Stuart Murdoch was determined that any repairs done remained true to the original, so when this unique restoration technique was suggested to him he responded: "Boldness, be my friend."

"I had faith in them and I wasn't disappointed," he said.

A feat of engineering

And now that the 103-year-old car is back up and running, Mr Murdoch is a very satisfied customer.

The Delage is difficult to drive, with heavy steering and its accelerator between the brake and clutch. ( ABC Radio Melbourne: Fiona Pepper )

"It is a considerable achievement for all those involved and, might I say, quite an achievement for Australian engineering," he said.

Motoring historian Douglas Blain, meanwhile, marvelled at the fact that this one priceless S-Type still remains.

"That it lives on in such a state of originality, and is maintained and used by its dedicated long-term owners rather than gathering dust in some sterile museum, is marvellous indeed," he said.

And Mr Guilfoyle thinks the digital repair technique may revolutionise restoration car repairs as mechanics like Mr Cowie become less dependent on dwindling car parts and fading skills.