""There's an intriguing but to me incomprehnsible one at Calibrating A Torque Wrench - How-To - Stock Car Racing Magazine
I spent about 10 minutes trying to figure out what the hell he's talking about and then gave up.""
I understood it within 5 minutes.
""To everyone who thinks fastener torque settings are optional and intuitive: I'm sorry but I'm not enough of a flower child and too much of an engineer to let this go by.""
Ah, there's the crux of the matter. You are living in engineer's world, not technician's world. So all those lug nuts in the Nascar pits that get tightened with an air impact? What's the spec on those and how do they know if the air guns are doing it within spec? I'll give you a clue, they are over-torqued.
""I'd be interested to know what procedure you've gone through that convinced you that you are always applying correct torque without using a torque wrench.""
For 35 years the cars that I work on don't come back with loose bolts just because I didn't use a torque wrench. When I raced go-karts for 5 years I never had a bolt come loose because of failure to use a torque wrench. The only thing I torqued was the head bolts. It's one of the very first things in this career that separates the technicians from the wannabes, can you tighten bolts by feel without stripping them?
""But the halfway house of "Well, I'll compromise and do head, rod and main cap bolts" is equivalent to saying the shop manual is wrong about some bolts and right about others. How can that be true, and how is it that you know which are correct and which aren't?""
Usually the things that are torque critical are either gasket sealing, like head gaskets, or distortion issues like rod, mains, and wheels. Most everything else is just to be tight enough that it doesn't come loose. Mission critical things like steering and brake components have safety wire or cotter pins. Everything else on a race car either has red lock-tite or locking threads.
So when a LeMans car comes into the pits and a major component gets changed out do you think all fasteners are tightened with torque wrenches?
I live in engineer's world AND technician's world. Professional technicians are under a time constraint. You only get paid so much to do a timing cover reseal on a V-6. If you took the time to hand torque every fastener it would take twice as long and the job barely pays 100% in the first place.
There's a torque specification for every fastener but even the factories don't torque all that many fasteners. Typically the factory, especially the Japanese, overtorque a lot of them.