Uncle Mellow:Don't forget that 4 litre RR motor was never meant to be used in luxury cars - it was meant for Army vehicles.
Extracts from the Cambridge-Oxford Owners' Club
"The engine itself was an alloy-block, short-stroke version of the familiar six-cylinder Rolls-Royce unit, which was used not only in Rolls-Royce and Bentley passenger cars up to 1959, but in many military vehicles. With a quoted peak of 175bhp it was much more powerful than the superseded 3-litre BMC C-Series engine, though this was never backed up by flashing acceleration figures or a dramatically higher top speed."
"Sales took off with a rush, but once the word got around that the engine was wasted on the rest of the car, demand slumped. Even with Vanden Plas trying all they knew to ensure top build quality, BMC could not sustain interest in the car. Sales had been expected to exceed 100 cars a week, but such figures were not realized and production was down to 200 cars a year by 1967. The Princess R was quietly withdrawn from production at the beginning of 1968, just before British Leyland would surely have killed it off."
It sounds like the quality of the car was not up to the engine.....
now I should be called 44 cars so far ... and 21 motorbikes !