If rod bolts got over torqued ( Faulty degree gauge) 90 degrees instead of 50,, ( I MIC'ed them and they still measure the same length as new) can they be set to proper torque, or are they garbage ??? was the damage already done ? Thanks
You probably should not have done that, but it probably depends on where you started the + 50 or +90 from. If you were starting from the low end of the torque range then I would say things are OK. If the bolts are the same length as when you started then they haven't "yealded" any, or streached in a permanent fashion. Everyone will say to replace them, but then money does have an influence on ones risk tolerance. For me I would have used the ones that came out. If anyone can point to a verified failure that is really connected to re-using the rod bolts I would like to read it. Remember, + 30 or + 70 may be OK, so + 90 or + 100 might also. But then I am old and poor. Larry
In my 40 years of building my own engines , I have never seen a rod bolt give way, But My experience is with the old "NON TTY" bolts. I DO hate to shell out another $90 for Bolts, but how am I going to feel if I reuse them and a rod lets go ?! I Hate these bolts !
Technically, if they haven't stretched they should be fine. The question is "How do you know they haven't changed length?". Did you measure each one precisely before and after they were torqued? You must not compare one bolt's length to another's... only to itself pre and post torque since no two bolts will be exactly the same beforehand.
Keep in mind that a bolt is not TTY simply because the torque is specified as a nominal torque plus X number of degrees of rotation. That only means it is a more precise method of achieving repeatable torque values for that bolt. If I were you, I'd check the FSM to see whether it states that new ones must be used each time... that would be an indication if they truly were TTY.
I have to admit -- I don't always torque bolts when putting things back together. I have a pretty good sense of "feel" for tightening bolts. But when it comes to bolts inside the engine, I am very careful to torque those. After all, once the engine is back together, you can't get to them, so they had better be right the first time. Having said that, I wouldn't take any chances, but get new rod bolts.
I already ordered New ones. I'd swear I felt these bolts "Giving way" as I pulled the # of degrees on them ! It's Pretty hard to check the length of each bolt "before and After torqueing them down". You Can't re-use them (supposedly). I checked the ones that got "over torqued" against a New One, and one of the Originals, they are all the same length, Exactly. Question: If ARP Bolts are so wonderfully strong, and don't stretch, WHY are NON TTY bolts that were used for 100 Years a bad thing ?! Yes, I did read the reports on TTY. ( you can write a "report" or" theory" on ANYTHING, making it "sound" Any Way You Want, ( they, the bolt manufacturers, are in the business of selling bolts (and probably the degree gauges also !) But if a non TTY bolt is "strong enough not to break", and" IS Reusable" ,meaning it doesn't stretch, and will tighten to the Same torque again and again, WHY couldn't they have just left Well Enough Alone?! This whole thing REALLY sounds like they purposely did all this to Make Sure, people would not bother to rebuild the engines and but a new one ! MAYBE, the TTY are good for the heads, but they should have left the rotating assembly alone. I'm Just not "Buying it ". ( the "theory" , obviously I'm Forced buy the BOLTS !) LOL
"Keep in mind that a bolt is not TTY simply because the torque is specified as a nominal torque plus X number of degrees of rotation. That only means it is a more precise method of achieving repeatable torque values for that bolt". ???? If you can't re-use these bolts, how can you possibly repeat the same torque value for that bolt ? they are telling you," once you have torqued the bolt, it's lifespan is done because it won't repeat the same".
There is no such thing as a TTY-specific bolt per se. ANY bolt can be torqued to it's yield point. The only thing that makes a bolt non-reusable is when the torque value needed to clamp two parts together approaches the yield point of the metal that the bolt is made from. So take for example a typical grade 8, coarse threaded 1/2" diameter bolt. Let's say for argument's sake that the maximum recommended torque that can be applied to it is 120 lbft (I'm too lazy to look up the actual values). What that means is that you can torque the bolt up to 120 lbft to achieve the clamping force you need, and then loosen it as many times as you want and the bolt will always return to it's original length and strength because you're stretching it in what's called its elastic range. (Imagine it as a spring that you only pull within a certain range... it always returns back to its original length.)
Take that same bolt and torque it to 200 lbft... if it doesn't outright break, it will have been stretched into what's called its plastic range. That's similar to the spring being stretched so much that when you let it go, it stays permanently deformed. That's what's going on when any bolt is used in a TTY application. The bolt is tightened so much that no matter what you do afterwards, it remains permanently stretched, and a side effect of that is that it is no longer as strong anymore either.
Again, just because you see that the torque needed for a given bolt is written like: "40 lbft +90 deg" it does not mean that it is a torque to yield application. It is simply a way to say the same as "torque to 90 lbft" (example only) but in a manner that results in a more consistent final torque than saying "torque to 90 lbft". That is why you can reuse bolts that aren't specifically torqued to their yield point. That is why you can reuse bolts even if their torque value is specified as "40 lbft +90 deg". That is why I mentioned earlier that unless the manufacturer specifically states that the torque values are TTY or the bolts are "one-time-use-only", then they are reusable.
OK, I understand all that , BUT, have you seen ANYWHERE, that it doesn't specifically say for these 3800 engines " REPLACE the bolts" , chiltons, motors, any machine shop, ? Try this, is a rod that has been "machined for ARP Rod bolts," stronger or weaker" than the same rod with factory TTY Bolts ? ARP will surely tell you it IS. (OK, Not the rod itself, but you get the idea). If it's better ( Again ARP will tell you it is) WHY not just put in stronger re-usable bolts to begin with. So the robotics can torque them better ? Cheaper ? These bolts that everyone seems to agree is best to replace, are not making the assembly (ROD) any "better". just more of a pain in the Butt and pocket, Just better for the companies selling bolts. ** AND, If torqing to 50 lbs and then 90 degrees is( just an example) the "same as" 75 ft pounds, WHY can't they just SAY "torque to 75 ft pounds To Begin with?? They are making Everything a lot Harder than it needs to be. I READ and understand your above explanation as to the "elasticity of a bolt". Would YOU rather have a bolt that is stronger and re-useable than one you have to replace and "pay for" every time you took it out ? I'm SURE "Racers" don't use these things. The only thing they are good for is if the engine is put together at the factory never to be worked on again. Yes, I'm old fashioned, bull headed, but Can't you See My point ?
The tighten to # ft/lb plus #* is much more accurate than a certain bolt head tq. When you turn it 90* it puts a more consistent stretch on every bolt. It helps from a few threads that don't have the proper amount of lube some kind of burr from throwing it all off.
Anyways this shouldn't even been an issue. There are plenty of good running 3800's out there. ------------------ Turbo3800E85F23 5spd spec5 firstname.lastname@example.org
[This message has been edited by Justinbart (edited 07-21-2013).]
WHY not just put in stronger re-usable bolts to begin with. So the robotics can torque them better ? Cheaper ? These bolts that everyone seems to agree is best to replace, are not making the assembly (ROD) any "better". just more of a pain in the Butt and pocket, Just better for the companies selling bolts. ** AND, If torqing to 50 lbs and then 90 degrees is( just an example) the "same as" 75 ft pounds, WHY can't they just SAY "torque to 75 ft pounds To Begin with?? They are making Everything a lot Harder than it needs to be. I READ and understand your above explanation as to the "elasticity of a bolt". Would YOU rather have a bolt that is stronger and re-useable than one you have to replace and "pay for" every time you took it out ? I'm SURE "Racers" don't use these things. The only thing they are good for is if the engine is put together at the factory never to be worked on again. Yes, I'm old fashioned, bull headed, but Can't you See My point ?
If you owned a auto company, assume there are average 1,000 critical fasteners in each car you sell, in bulk those fasteners cost $3ea if they are grade 8 and $2ea if they are lesser grade but both outlast the warranty period.
1,000 X $3 = 3,000 a car vs. 1,000 X $2 = $2,000 a car GM world wide sold 14,000,000 cars in 2002 as you can see it was a $14,000,000 decision
Of course this was a wild generalization, there are WAY more than 1,000 fasteners in each car that cost much less than $2ea and the end result us MUCH more the $14,000,000 (a year)
[This message has been edited by 1fast2m4 (edited 07-21-2013).]
It's a point of view. Gotta tell ya a story first. "Once upon a time" there was a regular "screw" with a straight groove in the top to make it work. But that was not good, so they made" Phillips" screws, that was not good enough, so they made" hex" heads, then "inverted hex "heads, then "Torx", then" inverted torx", then "torx with a pin" sticking up in the middle , so you couldn't use the tools you already bought. Then came TTY non re-useable bolts. Are ya sensing a "Pattern" here ? It's the American way, "get into everyone's pocket for as much as you can , as often as you can". If you want to believe that this bolt will make an engine last any longer, you're entitled to your "opinion", as I am mine.
AHA, you just made my point ! they are cheaper, and every time they change a fastener you need to BUY a new TOOL to make it work !
I did a frame off restoration on a 1967 Corvette a few years back, If I ever have to use another cotter pin in my life it will be to soon, I swear Castle nuts and cotter keys EVERYWHERE . I'm fine with the evolution of technology, even if we are just talking about nuts & bolts, we don't even need lock washers anymore