I give her the same answer as you: my dad. My grandfather had a farm in North Africa where my dad grew up during WWII. No gas, so my grandfather built a CO trailer to feed the carburetors on the car and farm machinery. They did all their repairs and my uncle learned how to machine parts from blocks of soft steel with a drill press and files. Plus the usual farming chores.
Both my father and mother grew up on dairy farms in WNY.
Dad went through the Depression. So, he never hired anyone to do ANYTHING with one exception. At 500K miles he had the Detroit Diesel engine on the White Freightliner Semi tractor rebuilt.
I think if he had the machinery to rebuild the engine himself he would have. He was a very good diesel mechanic and had been a field mechanic after the war for Yale & Towne.