So you are using the parts from the free engine to fix the existing. Sounds like a good plan. This event is the same as 5 years of mechanics training in one day. So it's a good thing, although may not seem so right now. The cost was very low for the amount of knowledge gained.
So as my Mom would say about everything I did, "be careful, that could poke your eye out"

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn