6.1 Hemi Internals.
Just because the torque spec includes a 90 degree turn doesn't make the bolts "torque to yield".
The old FWD turbo head bolts were torque to yield and included a visual that showed if the threads were elongated the bolt was junk, but otherwise could be used again.
This is similar to what I remember seeing when I was messing with those motors:
Note that it says to replace them only when the bolt shows it is necked down or elongated.
The service manual for a newer Challenger I just checked doesn't have any of that info. Could be because they expect the bolts to be replaced every time so why worry about it. But I think it is because the bolts aren't designed to stretch because they are a "torque to angle" bolt instead. Completely different.
Per Fel-Pro: "Torque-to-angle bolts are fasteners that are tightened to a specific amount of rotation or degrees to ensure the proper amount of clamp load is applied."
I think the problem is that people assume that if there is a degree of rotation in the torque spec then the bolt must be a "torque to yield" bolt. But it doesn't mean that at all.
Just because the torque spec includes a 90 degree turn doesn't make the bolts "torque to yield".
The old FWD turbo head bolts were torque to yield and included a visual that showed if the threads were elongated the bolt was junk, but otherwise could be used again.
This is similar to what I remember seeing when I was messing with those motors:
Note that it says to replace them only when the bolt shows it is necked down or elongated.
The service manual for a newer Challenger I just checked doesn't have any of that info. Could be because they expect the bolts to be replaced every time so why worry about it. But I think it is because the bolts aren't designed to stretch because they are a "torque to angle" bolt instead. Completely different.
Per Fel-Pro: "Torque-to-angle bolts are fasteners that are tightened to a specific amount of rotation or degrees to ensure the proper amount of clamp load is applied."
I think the problem is that people assume that if there is a degree of rotation in the torque spec then the bolt must be a "torque to yield" bolt. But it doesn't mean that at all.