[freebeard]

https://en.wikipedia.org/wiki/Scuderi_engine

The Scuderi engine, formally called the Scuderi Split Cycle Engine, is a split cycle, internal combustion engine invented by Carmelo J. Scuderi (April 13, 1925 – October 16, 2002).[1] Scuderi Group, an engineering and licensing company based in West Springfield, Massachusetts and founded by Carmelo Scuderi's children, is testing a working prototype of the engine that was officially unveiled to the public on April 20, 2009.[2][3][4]

The inventors heirs rode this one into the ground. I think it could have worked as a box four. They sunk all their investment capital into a proprietary inline four block, that wasn't modifiable for test purposes.