Backed by the success stint of Nano as the world’s cheapest car, Tata Motors is schematizing to expand it for the diesel variant. The proposed diesel version will be fitted with a 1000cc engine replacing the existing 623cc engine and equally the cost will also vary for this models, it is learnt. The complete sketch for the diesel version will kickoff by this year end, when the company will have finalized the 2-cylinder diesel engine format, said the company sources.