High,
I don't have a model of the OS160, but i do have a very basic model of the OS 140RX. Unfortunately it's not very precise, but if you have Solidworks you can understand how it was built. Modelling an engine is not that hard, after all it's a combination of very basic shapes. To get started, just try to find some detailed tutorials or modelling manuals for your CAD software. You will need a lot of practice though... I built my first 3D airplane model probably around 1997 in AutoCAD, but trust me, you don't want to see that one