To some, it is a dream job, but sometimes the reality can be a nightmare, as exemplified by the situation in which British classic racer and journalist Mark Hales finds himself.

Hales, a respected writer, is looking at a NZ$206,000 bill and bankruptcy after a judge ruled he blew up an engine in a rare Porsche 917 he was evaluating for a magazine in 2011.

The car is owned by veteran F1 and sportscar racer David Piper and the ruling has set a legal precedent and could lead to more claims for the cost of repairs from people using, testing or racing someone else's vehicles.

Website Evo.co.uk said Hales had claimed the damaged was caused by a mechanical failure that allowed the car to jump out of gear and over-rev. The engine had to be rebuilt in Germany at a cost of NZ$68,500 which Hales has been ordered to pay on top of a six-figure legal bill after a bitter legal battle.

Piper had countered that Hales did not engage the gear correctly and Judge Simon Brown ruled that way.

The judge said the evidence "overwhelmingly" pointed to the engine damage being caused by over-revving following Mr Hales' failure to properly engage gears.

The Grimsby Telegraph reported that the judge described the journalist as "a most unreliable witness whose evidence was creative, inconsistent, self-motivated and incredible".

Hales told paper he felt the judgment and "gratuitous destruction" of his character was "unfair".

He claimed he had only done about 15 laps with the Porsche, which has since been sold.

He added: "The 917 was notoriously difficult. All the best drivers had problems and there were lots of engine failures; Vic Elford lost victory at Le Mans in his 917 because of the same problem.

"It looks like bankruptcy for me."

- © Fairfax NZ News