I was using the engine example as an analogy in an apparently failed attempt to help you appreciate the complexity involved. Mechanics in general will feel their way around an issue, but almost universally have access to paid repair databases when non-intuitive and complex issues come about.

You might recall that we're all talking about manufacturing equipment that was exfiltrated as war reparations.

I'm much less convinced than you are about the availability of accurate and detailed manuals. Which is why I keep steering the conversation to more murky engineering projects.

But I do want to circle back to say that I did at some point higher up gloss over the importance of things like torque and clearances. I'm not trying to say that those are things you can just intuit. Even if we could both probably dig up an old mechanic who tightens things by feel.

I don't understand the problem. You take the equipment, the manual, the guy who used to read the manual and maintain the equipment and the guy who wrote the manual and designed the equipment.

Did we mention that the manual was burned, and the guy and the guy who wrote the manual died in the explosion that burned the manual?

It was at the end of a massively destructive war of annihilation.

I think everyone has access to full shop manuals in soft copy these days. I imagine it's a lot like writing code. You remember how to write a for loop (oil change? a brakes?) but have to look up API docs for more esoteric functions (a clutch job?).

FWIW here are Nissan factory manuals in all their glory: https://www.nicoclub.com/nissan-service-manuals