As far as I know it is not legal to alter the reading of an odometer. This may only be a NSW thing. It is to prevent fraud.

The odometer is supposed to measure the distance a car has travelled not how long you have had an new engine in the car. Suppose you were to buy a five year old Falcon with 30,000km on the clock and then you find out that it is an ex-taxi with 600,000 on the clock but they fitted a new motor so they zeroed the odometer.

With a Mini there is very little chance of getting caught.
But...
When you sell the car the new owner may find this thread and find you have altered the odometer reading. He may not be happy that the indicated mileage is not a true reading.

Yeh cool. I won't be selling the car

Or, he may be happy with your explanation that the mileage indicates the mileage put on the reconditioned engine, and that the true mileage of the mini is unknown as one might expect of a car of that vintage. How many times might the odometer been around the clock on a 40yr or so old car.

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Especially since the odometer only goes to 100,000 miles or kilometers , I think it would be viewed diferently if it was a later model car where the odometer went to 1,000,000 klms and you'd replaced a 350,000 klm one with 0 .

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