A sterling engine has 6 items for its recipe. You can view the other items with the brown up arrow next to the furnace in the crafting book.
EDIT: I felt like I was missing something and I was. Sorry I thought you didn't know that you could 'scroll' through the items (it looks like you already did). Hope you found out what was wrong. I've seen some people experience the same issue but I'm not too sure if it's a game bug or user error.