[PANAVIA]

Haynes has good technical books , but not much on theory , just repair.

I would go into the used bookstore and try to find something from the 1950's or 1960's , you can find some real jems there that are technically awesome and mechanical.

I have a jaguar engine book from 1959 that is awesome mental vacation material.

also Popular mechanics used to make how to guides in the 1950s that you can find that are a blast from the past and a good foundation for modern kids wanting to understand engines.

--Steve