W hen it comes to risk versus reward, the V12 engine is surely the ultimate way to straddle the thin dividing line. On the one hand, a big 12-pot is massively at odds with today’s drive towards economy and environmental restraint, but on the other, it’s an automotive engineering extravagance to stir the soul. And in the Jaguar XJ-S and the Aston Martin DB7 Vantage, two different takes on the V12 can be experienced for a fraction of the price of a new eco-box. But should you indulge, and if so, which of these platform sharers is most worthy of a beleaguered fuel budget?
JAGUAR XJ-S
Jaguar’s V12 first appeared in production in 1971 under the nose of the Series 3 E-Type, but its origins are in the early ’60s, when it was conceived as a quad-cam race engine for the XJ13 Le Mans prototype that ultimately never saw competition. Even so, the race V12 provided useful lessons for a roadgoing version, chiefly that the four cams with their partially geared drive were too noisy for the expected refinement in a Jaguar saloon. As a result, the definitive production version of the V12 offered a 5348cc capacity with a single camshaft on each bank. Despite this it was still a high-performance engine, and being mostly aluminium, weighed only 36kg more than a 4.2 XK six.
Unlike other models, the XJ-S was the only Jaguar to have been conceived and developed with solely the V12 engine in mind. Based on a shortened XJ platform and styled by Malcolm Sayer before being finished off by the in-house jaguar team after his untimely death, the XJ-S was intended to
