man im 100% they have 6month warrenty on rebuilds
thats a really poor warranty, a couple of builders i know for rotary engines are giving 2 years or 24000 mile warranty, even on large power builds, INCLUDING drag drift and track days! thats build confidence!!
shouldnt matter if its a new owner, fact is, the engines been built and not to a good quality if its broke so early. perhaps the company who has built the new spec engine could approach the other company on your behalf, and provide them with the evidence found when dismantling the old build??
you might not get a refund, or a replacement, but you may get something
gutted for you though, huge costs