done some research, your right it originally was never a 1.7 but a 1.4. this one has been converted at some stage in its life, is definately 1.7 though.
i found the following comment about the car:-
This car is really a nice performer, leaves behind almost every car from its class, consuming fair amounts of fuel (unless you dont floor it too much)... handles like heck.. Fortunately the spares are cheap, and once you can fix things on your own, and become independent from sh*tty Renault service, running this car becomes really affordable.
After 12 - 15 years of service - it may become dangerous - the engine performance is still the same, but the key systems become highly unreliable.
The general opinions about the original engine seem to be stay away from lots of different reviews. But then this engine obviously isnt standard. i m confused about what to do now