So, I'm developing a vehicle based on a Sroka aircraft tug. Here's the mesh so far, doesn't have any interior or anything that would make it drivable in Beam, but it's coming along pretty well! Anyway, back to the real question: can you use an engine model from a default vehicle in a creation? If so, how, and would I have to get permission? The engine I'm after is 3 to 4 liter inline four. For anyone wondering, the engine is located just rearward of the cab. Thanks!
To elaborate a little on what Sithhy said, every official vehicle has all parts as separate meshes, so the engine can easily be copied and pasted into your file. If you don't know how to import official vehicles in a 3d modelling software, check out the wiki page for assistance. And as Sithhy said, don't forget to credit the devs when you are finished