While the full version is paid, the free demo on Steam offers a deep look into engine design. You can choose different configurations (V8, Inline 4, etc.) and tune everything from the bore and stroke to the fuel system.
If your interest is more about the "engineering" and seeing if your creation actually drives (or crashes), these sandbox games are excellent: car-constructor-pc-game-free-download-full-version
: A unique simulator where you design the frame and suspension of a car from individual beams and nodes. It is highly technical and rewards players who understand structural integrity. A Note on "Free Full Version" Downloads While the full version is paid, the free