The great cars let down by their engines

Slide of There have been so many cars over the years that deserved to succeed - and might have done so if it wasn't because of their engine. It might be hideous unreliability, terrible refinement or a lack of power, or a combination of all three, but by choosing the wrong engine for these cars, they were all doomed from the outset: Slide of MGA Twin Cam (1958) With its gorgeous lines and sweet handling, the MGA is a highly desirable classic. Most came with a 1.5 or 1.6-litre engine with overhead valves, but more than 2000 got a twin-cam engine developed from the standard MGA's B-Series unit. Fitted only to the MGA, this double overhead-cam engine demanded top-grade fuel and the ignition timing to be spot on. Without both at all times, the pistons were easily holed and with a propensity to burn oil even when in rude health, buyers avoided the MGA Twin Cam at all costs. Slide of Chrysler Gas Turbine (1963) We're not mocking Chrysler by including this car that never reached full-scale production – after all, where would we be if car makers didn't push the boundaries? But the Chrysler Gas Turbine was an experiment too far. Just 50 were made and lent to families for real-world evaluation; they concluded that limited acceleration, shocking fuel consumption, a complicated starting procedure and poor refinement were too high a price to pay, and a regular V8 would do the job far better. Slide of Hillman Imp (1963) The Imp had the makings of a truly great car, with its light weight, slick gear change and zesty engine. But while the all-aluminium 875cc water-cooled 'four' mounted in the rear ensured the Imp was tremendous fun to drive – genuinely good enough to take on the Mini – it was also this powerplant that would be one of the Imp's many failings. As well as problems with the pneumatic throttle of early cars, overheating often led to blown head gaskets and warped cylinder heads or even distorted blocks. Later cars were largely sorted, but the Imp's reputation was shattered by then. Slide of NSU Ro80 (1967) Of all the sub-standard powerplants here, the Ro80's Wankel unit was perhaps the most catastrophically weak – it was bad enough it nearly destroyed the company that made it. While the Ro80 was a brilliant car with its ultra-aerodynamic design and semi-automatic transmission, total engine failures within the first 10,000 miles were common thanks to the rotor tips wearing, leading to a lack of compression. Warranty claims spiralled out of control, leading to NSU collapsing into the arms of Volkswagen in 1969. The NSU name disappeared from view in 1977, when the Ro80 also died. Slide of Austin 3-Litre (1967) We're stretching the great cars bit with this one admittedly, but you can't deny that the Austin 3-Litre is an intriguing car that could (should?) have been great. Large and luxurious, the 3-Litre should have featured decent ride and handling but had neither, while its smooth straight-six was based on the one seen in the Austin Healey 3000. Sadly it didn't prove as long-lived in the 3-Litre though and many of the 9992 examples made were scrapped because of premature engine failure. Slide of Triumph Stag (1970) An affordable four-seater convertible with V8 power – what's not to like? Especially when it's also got smart Michelotti styling. But that V8 was a 3.0-litre unit unique to the Stag and it suffered from a litany of glitches including weak timing chains, warped cylinder heads and poor-quality castings that led to a lack of coolant flow and consequent overheating. In seven years just 25,939 were made, and just 10% of them made it to America which was a key would-be market. British Leyland had hoped for so much more: a car to rival the Mercedes SL in both sales and stature. Slide of Jensen Healey (1972) A two-seater sports car resulting from a collaboration between Jensen and Healey, powered by a Lotus engine. The world's first production car to feature an engine with four valves per cylinder, the Jensen-Healey should have been sensational, but complying with US safety legislation spoiled the looks and that twin-cam 16-valve engine turned out to be a complete disaster. Prone to overheating resulting in warped cylinder heads, the Jensen Healey's powerplant was just one of many weaknesses that buyers had to contend with. Slide of Triumph Dolomite Sprint (1973) Here's a conundrum for you; the Triumph Dolomite Sprint is here because of its engine, and despite it. The Sprint was based on Triumph's Dolomite saloon so it offered performance with luxury. But the all-alloy engine was prone to overheating leading to blown head gaskets and warped cylinder heads, the whole thing often kicked off by the viscous fan seizing up. Slide of Volvo 260 (1974) Sure it was boxy and offered little in the way of driving pleasure, but the Volvo 260 provided safe and comfortable family transport and it was s