X2. The rod bolts are the most abused parts in any motor and TTY bolts are meant to be used one time only as the term TTY means 'torque to yield'. When you go to yield on a bolt you are taking it past the normal stretching which stops just before yield, which is permanent stretching that deforms the bolt by making it longer. In short, you have overtightened the bolt to be trying to pull it in half. Do it twice and you are begging for failure.
Don't ask me why the engineers do that. They claim the act makes the parts more reliable in use but I think it's bullsh-t to force you to buy more parts as engines never needed to do it before.
Ford stated that the bolts could be used twice when they first began to use them but either they began to get failures themselves in repairs or the above reason I gave convinced them to quit saying you could reuse them in the service manuals.
TTY is why you cannot use a normal 'torque to' number, you get a falloff in torque when a bolt begins to twist in two, the number quits going up and you don't know when to stop then. And every bolt is slightly different, why they began to use angles as the last tighten spec instead.
Your rod bolts have already been tightened twice, they have to do it once when machining the big end and then the second time when the engine is assembled. Correct procedure is to change all bolts there.
Yeah, I know it sucks, I come from the '60s where we didn't junk parts like that, they still had some value. Now the OEMs make you cycle through that stuff to get more money out of you at repair time.
