Engines used in general aviation have interchangeable parts from almost 100 years ago. You could warp a Lycoming engine mechanic in from 1942 using your time traveling phone booth and he'd be able to fix your 172 of any vintage.

Yeah, but that's because general aviation engines are stuck in a time capsule from the 1940'ies, not because they are particularly good engines by today's standards. Exception being Rotax on the low end.