If the car is fit for purpose, you will struggle to get your money back. So if you have driven the car more than 50 mile, it has been 'fit for a purpose'. -It drives. But its not good. you have a few options- 1. New engine = expensive, prob £550 fitted. 2. Replace the rod = £300 -- I cant believe its the rod, without other major damage elsewhere. 3. Easy option - sell the car via a motor auction, of you have paid £1000- you wont lose to much,as a trader will buy it.