It can be done... (no issues over here regarding the import of parts only) although most of the suppliers will be reluctant to deal with just a single bare crankcase.
There were a number of excuses cited, some related to tax breaks and such for completed assemblies within India.
The best way we have found is to purchase entire engine assemblies, have them dismantled and packed into a full container for transport. The small guys get paid, the government gets to push its policy and everyone involved eats for another day.
dieselgman