IS MY VIOLET A SLAPPER?

QA dull, metronomic clicking comes from the engine of my 1975 Datsun Violet when accelerating with the engine cold. It sounds faintly diesel-like. I’ve been reliably told it’s ‘piston slap’. The car doesn’t burn any oil. Should I worry about it? Norman Freeman, Duisburg

AThe solution is to get the engine rebored and fit new pistons – but since it’s not using oil and it’s only a problem when cold, you can safely ignore it for a good while longer. It won’t cause consequential damage. It may be the result of an inept previous rebuild, natural wear-and-tear or accelerated wear due to an overheating issue and partial seizure in the past.