How the internals of an engine actually interact while the engine is running is something rarely seen in action. You can look at animations or a select few motorized cutaways that spin slowly, but seeing the whole system working in real time is a treat. Luckily, companies such as GoPro now make cameras compact and durable enough that you can stick a reasonably high-resolution unit just about anywhere on a car—including inside the engine.
Read the full article on Hagerty.com:
Expensive form of diagnostics. Burn up a GoPro worth several hundred dollars. But dude! You need to fix that power steering fluid leak. Cannot be good for your engine. Like running gasoline with 2 cycle oil through a 4 cycle engine!