Engine/Transmission (1994 - 1998) Stud re-torque overkill??

[JGheen]

Can studs ever be re-torqued too much? Just wondering how many times during the life of one's engine can the studs get re-torqued to a point where they may break off or stretch too much due to excessive re-torqueing, if that is possible? I would think as long as it's the same torque value everytime, they should be Ok, but if your drag racing every weekend, for example, and really hammering on the engine and doing a re-torque after each weekend(doesn't have to be "every" weekend ) of hammering on the engine, does that weaken them at all??



Thanks, Joe

 

[Forrest Nearing]

you shouldn't be retorquring like that...



the reason for a retorque is to make up for gasket compression after heat cycles...



you can retorque MANY times as long as you do not exceed the fasteners plasticity threshold...



you torque to a value, then when the engine heats up, it stretches the fastener and furthur compresses the gasket... you then retorque to make up that compression...



mark the nuts when you retorque, and once you reach the point where the nuts do not turn any farther than they did before to achieve proper torque value, you shouldn't have any reason to retorque again.



you will want to do all of this BEFORE you start laying the power to it!!!

 

[JGheen]

Well, I did do all my re-torques(3 to be exact and scribing a mark on the nut) before I really started hammering on it. I don't drag race every weekend or anything but I just heard through the grapevine that some, if not most, who drag race or really beat on their engine a lot for example, maybe not a daily driver, do a re-torque just about everytime after a good hard weekend of running. My last re-torque about a month ago ended up about 1/16" tighter on the scribe mark and I am wondering if maybe one more wouldn't hurt just to be safe.



Joe

 

[Forrest Nearing]

hmm... I guess it couldn't hurt if they're backing off like that!!!



but to answer your question, as long as you don't exceed the fastener's plasticity threshold, the retorques won't hurt anything

 

[JGheen]

They're not backing off, that was just the last measurement I ened up with between the scribe mrak on the head and the nut. The first one was about 1/4", second about 1/8" and as I said above, the last one turned out to be about 1/16". I guess one more re-torque would probably end up right on the scribe marks.....



Thanks for the advice Forrest!



Joe