WHEN motor car design was less advanced than it is today, the most obvious way of proving, what an engine would stand up to was to discover the point at which it would break down. For this reason the Daimler company some years ago instituted ” destruction tests” ; the unfortunate engine which was selected for the sacrifice was placed On an engine bed and run at 3,000 r.p.m. under :nill load for 21 hours nonstop. Similar tests are in operation today, but they are no longer destructive, for

wear or fracture is seldom discovered. Every week of the year one Daimler and one Lanchester engine are subjected to special ” investigation ” tests. Each is run all out for 21 hours, as in the old tests of this time, three hours are spent in first gear, three in second, 14 in third and three quarters of an hour in top, the remainder being occupied by 15 minutes in reverse. The mileage equivalent is over 500, of which 420 miles are done in third gear. Each engine is then completely stripped and microscopic examination is made of all parts. One great advantage of the

tests is that they enable any new components, such as different type sparking plugs, piston rings, etc., to be tried out more strenuously than could ever be possible on the road. In fact similar conditions &mid only be reproduced by a 21 hour all out non-stop run on a racing track ; and as runs of this duration are not permissable at Brooklands, they would have to be carried out on the Continent. The factory tests are at least equally efficient and they have the further asset that they allow refinements and modifications to be made without delay.