GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
Gotcha - I'm not all too familiar with the 139, just that the project was merged with Bramo's 323 for the 801 development.The BMW 139 was with even worse reliability problems than the early 801s, due to the in-built heart failure so to speak.
Even if it was a workable engine, the resulting aircraft designed around the two 139s would've been the size & weight of Bf 110/210.
I recall overheating issues with the 139's installation in the early Fw190 prototypes, but that was mainly attributed to the cowling design at the time.