Finding an Engine to Disassemble

I’ve been curious in car engines, and have watched videos from youtubers like CarThrottle and EngineeringExplained, but I want to know where I can get hands on experience or a cheap engine that I could disassemble to see inside, because I would like to have some knowledge on the subject and youtube videos only go so far. I’ve heard you can buy them at scrapyards, but I have no clue how that works, so if anyone has an idea that would be awesome, Thanks.