Some folk put a dial indicator on rod bolts and "stretch" them a certain amount to determine proper tension. But that doesn't do anything that rotation-based torquing doesn't.
The engine shop I use does that quite frequently.
From everything I've seen, a TTY is a much better fastening method when condition of threads is not known or is known to be less than ideal.
That being said, any critical fastening (even if utilizing a TTY bolt) should be done with threads that were cleaned by proper methods and done with specified lubrication. With proper threads, standard methods should provide uniform results.
I know in many commercial machine shops, cleaning threads properly is not something that is often done and damaged threads are sometimes hard to avoid, so I can see where torque to yeild is preferred (less concern on "prep", and reduces the margin of error when poor prep is done).
I know on high end race engines (Sassy being one shop that I know does it), ALL threads are checked (even something as mundane as an oil pan bolt).
One question though is as the article states, we have all reused head bolts in the past and have no issues, but they state TTY bolts are no different in metallurgy than the common head bolt (used years ago) so why the BIG concern all of a sudden? Technically all old fasteners were TTY, just we did not tighten them in the fashion we do now. I know when the LBZ's first came out and several had glowplug tips fall off, several trucks at my local shop were out of commission for several weeks as the TTY head bolts were backordered and there was the impression that the engine would be junk if the old ones were reused......
In the past, many used new bolts in high performance builds as metal fatique was a concern, but it was not because of the method used to tighten, but rather the number of times a fastener was torqued (no different than using a TTY fastening sequence). It was then found that in high performance applications (especially) high rpm motors, rod bolt stretch became a concern and a better quality bolt was needed. It was not due to the method used to tighten, but the metallurgy of the bolt.
Also, what is different metallurgically that makes an ARP bolt able to withstand multiple retorquings without fear of elastic failure?
