Mine was a build a long time ago. My cousin and I each got the Renwall Visible Engine kit. This was when Renwall was still in business, and the engines were based on the Big Block Dodge engine. At 1/4 scale, they were designed to operate a lot of the internal parts. When we each got our's done, we set them up to run them, mine ran as long as the batteries held up for the Electric motor that turned them. Rocky's started to turn, then some forces on the pistons caused it to pop the cylinder banks loose and the engine seized up. (Revell makes them with a hand crank now, with the batteries only for the ignition bulbs)
I kept my engine, running it once in a while, until the sun in the back window of our station wagon warped it when I was 12.
I am like an engine builder that became a watch maker,,,,,,I get my pleasure from some very tiny airplane parts, compared to that engine model.
Rex