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Two hours on a 4 bolt 468", steel crank, HD I beam rods with ARP bolts, Kieth black 9.5:1 pistons. Seemed to lock up so we pulled it down and THREE rod bolts had loosened up. #8 was bad enough to allow the cap to lift and the bearing to spin.

I guess a stretch gauge is in my future.. I have always just torqued to spec and never had a problem. Anybody else have this happen? It sure didn't take long, and it happened when the motor was idling. The good news is the cam broke in fine and everything else looks perfect. I guess I pull it apart, grind the crank, and put it all back together. Just sucks to have a brand new piece do this, but I guess it could have been much much worse. I always heard guys talking about the stretch gauge being the only way to go and I guess now I'm a believer too..... River Dad
 

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steelcomp was here
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Sounds like someone forgot to tighten some bolts. (Well someone was going to say it, might as well be me!):)sphss
 

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E-7 Sheepdog (ret)
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Sounds like someone forgot to tighten some bolts. (Well someone was going to say it, might as well be me!):)sphss
I go thru those about 3 or 4 times, rechecking the torque, just to reduce my self-paranoia that I missed one, before I put the pan on. Mains too.

Easy to miss just one, or more.
 

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Sounds like someone forgot to tighten some bolts. (Well someone was going to say it, might as well be me!):)sphss
Hey, we agree on something.:)devil
 

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LOL, you are just to much Steel,

Go ahead........

Don't worry I won't come back & make this into a bickering fest that Rex needs to oversee.

Mr. Steel you have the floor.

Carry on.
 

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Two hours on a 4 bolt 468", steel crank, HD I beam rods with ARP bolts, Kieth black 9.5:1 pistons. Seemed to lock up so we pulled it down and THREE rod bolts had loosened up. #8 was bad enough to allow the cap to lift and the bearing to spin.

I guess a stretch gauge is in my future.. I have always just torqued to spec and never had a problem. Anybody else have this happen? It sure didn't take long, and it happened when the motor was idling. The good news is the cam broke in fine and everything else looks perfect. I guess I pull it apart, grind the crank, and put it all back together. Just sucks to have a brand new piece do this, but I guess it could have been much much worse. I always heard guys talking about the stretch gauge being the only way to go and I guess now I'm a believer too..... River Dad
River Dad,

Sorry to bring elements of the past to your thread. Not the intent.

I hope you find some answers in hear to figure out what happened & try to avoid in the future.

There is a huge wealth of knowledge on these boards. So much that it has caused some issues in the past.

Good luck.:)hand
 

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Two hours on a 4 bolt 468", steel crank, HD I beam rods with ARP bolts, Kieth black 9.5:1 pistons. Seemed to lock up so we pulled it down and THREE rod bolts had loosened up. #8 was bad enough to allow the cap to lift and the bearing to spin.

I guess a stretch gauge is in my future.. I have always just torqued to spec and never had a problem. Anybody else have this happen? It sure didn't take long, and it happened when the motor was idling. The good news is the cam broke in fine and everything else looks perfect. I guess I pull it apart, grind the crank, and put it all back together. Just sucks to have a brand new piece do this, but I guess it could have been much much worse. I always heard guys talking about the stretch gauge being the only way to go and I guess now I'm a believer too..... River Dad
Just be glad it happened when the engine was idleing and not at a 1000' into a 1320' pass like someone else I know... :D The damage in those circumstances are much more severe...
Best of luck to you
 

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"New"

Well I can relate, been there done that..........But, the info I got here, (or HB, it was a long time ago) was that the ARPs, or any aftermarket fastener, needs to be exercised into the first use. Torqued, loosened, torqued..like 4 or 5 times to "seat" the threads, then finally torqued.........Also, those bolts should be carefully measured, (mic'd) for length and recorded before they're used, then re measured after disassembly to see if they have stretched beyond re use. I think the specs say if they have stretched .001 or .002 during use, do not reuse them. Any chance the bearings were mis boxed? Did you measure clearance on each rod bearing during assembly? How are the mains?.........AND, what is the history of the rods?......New, used ? Were the rods re sized after the ARPs were installed?..........I have seen a lot of parts and pieces for sale, very reasonable, that state "dyno time" only.......IF those rods were new, and the bolts in them were new, it would seem there were other issues. Rod bolts don't just "loosen up"..........Are the pistons Hypers? The top ring gap is critical IF they're Hypers...........Hope you sort it out, I know that "Mysteries" are a bitch........Ray
 

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Amatuer
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Two hours on a 4 bolt 468", steel crank, HD I beam rods with ARP bolts, Kieth black 9.5:1 pistons. Seemed to lock up so we pulled it down and THREE rod bolts had loosened up. #8 was bad enough to allow the cap to lift and the bearing to spin.

I guess a stretch gauge is in my future.. I have always just torqued to spec and never had a problem. Anybody else have this happen? It sure didn't take long, and it happened when the motor was idling. The good news is the cam broke in fine and everything else looks perfect. I guess I pull it apart, grind the crank, and put it all back together. Just sucks to have a brand new piece do this, but I guess it could have been much much worse. I always heard guys talking about the stretch gauge being the only way to go and I guess now I'm a believer too..... River Dad
My father has described something to me he calls "cold flow". You tighten up a bolt or nut or whatever and the metal takes a minute to settle and that settling can leave the bolt somewhat loose. So he always said to torque, wait a minute and retorque again and a third time if you are paranoid.

Post Edit: Looks like Moneypit decribed something similiar.
 

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steelcomp was here
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LOL, you are just to much Steel,

Go ahead........

Don't worry I won't come back & make this into a bickering fest that Rex needs to oversee.

Mr. Steel you have the floor.

Carry on.
Morg. I was SO kidding!
Sorry you didn't see the humor.:p:)hand
 

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steelcomp was here
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26,512 Posts
My father has described something to me he calls "cold flow". You tighten up a bolt or nut or whatever and the metal takes a minute to settle and that settling can leave the bolt somewhat loose. So he always said to torque, wait a minute and retorque again and a third time if you are paranoid.

Post Edit: Looks like Moneypit decribed something similiar.
What Ray is talking about is torque cycling. With new fasteners, there is a lot of friction between the threads, but mostly under the head of the bolt and washer or clamping surface, These new surfaces are relatively rough, and need to be "mated" to each other, or basically polished under pressure. As you tighten and loosen the fasteners, these surfaces become smoother if you will, and have far less friction than when brand new. Less friction = less torque required to turn. It's the amount of rotation that causes a bolt to stretch, and with less friction for the same given amount of torque, a fastener will turn further and stretch more. 60# of torque with a new fastener may yield .003" stretch, while 60# with a cycled fastener may yield .004. This is also why the type of thread lube you use is critical when torquing. You can always check this with a witness mark on the fastener. Torque a new fastener and mark the head or nut. Then cycle the fastener a few times and then re-torque. You'll see the fastener rotated further after cycling. If you don't cycle the fasteners, there is a chance that they will "mate" under pressure and take up some of the pre-load, and in fact, may come loose.
 

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Morg. I was SO kidding!
Sorry you didn't see the humor.:p:)hand
I was just so excited to think we actually agreed on something that I could not see the Forrest through the trees.:)sphss:)hand
 

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Some guys never learn.
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What Ray is talking about is torque cycling. With new fasteners, there is a lot of friction between the threads, but mostly under the head of the bolt and washer or clamping surface, These new surfaces are relatively rough, and need to be "mated" to each other, or basically polished under pressure. As you tighten and loosen the fasteners, these surfaces become smoother if you will, and have far less friction than when brand new. Less friction = less torque required to turn. It's the amount of rotation that causes a bolt to stretch, and with less friction for the same given amount of torque, a fastener will turn further and stretch more. 60# of torque with a new fastener may yield .003" stretch, while 60# with a cycled fastener may yield .004. This is also why the type of thread lube you use is critical when torquing. You can always check this with a witness mark on the fastener. Torque a new fastener and mark the head or nut. Then cycle the fastener a few times and then re-torque. You'll see the fastener rotated further after cycling. If you don't cycle the fasteners, there is a chance that they will "mate" under pressure and take up some of the pre-load, and in fact, may come loose.

I hate to hear about anybody breaking motor parts but I sure get a great education sometimes when it happens.

Very informative thread.
 

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Discussion Starter #19
Hey guys, i appreciate the advice, even the one's that said I just f'd up and didn't tighten them all. I would never be bold enough to suggest that I am incappable of pulling a bone head move and mis a few. I've screwed up before and I'm sure it's a matter of when it happens again, not if. But guys, I swear, I tightened all of them. I even went back over them several times.

Something I didn't do was cycle them several times prior to a finish torque. They were brand new bolts in a set of used rods that were resized after the bolts were installed. The pistons are hypers and the top rings were ground to the KB specs, as I recall a really large top gap (.034 on the top ring).

I guess I could see if just one wiggled a little loose, but 3, this is killin me. I haven't had the wrench calibrated in a few builds, but I doubt that it would be that far off!! The main bearings look fine along with the rest of the motor.

If I did use a stretch gauge, would the correct procedure be to cycle the bolts a few times, torque to spec and then measure the stretch to see if they are in spec? Even if I did screw up, I think I might start using a gauge even if it's just to double check myself. By the way, piston skirts and cylnders look great, no signs of scuffing or anything. Don't you hate it when the only logical solution points towards you being a knucklehead?? LOL

Thanks for the info guys, and if nothing else I'll chalk it up as a lesson.......
 

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Discussion Starter #20
You know the thing that's funny, I think about all the threads that I have read and remeber saying to myself, "Damn that sucks!!!". Irony at it's best, here I am. All I can do is laugh about it now. The good news is that there really is a wealth of info here on the boards and I can honestly say I think I've learned more through reading about other's broken parts and all the advice than I have from anything else. All the info you guys put out is very appreciated and it helps a ton.............. River Dad
 
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