Do head studs really break?

TheSh111t said:
Thank you.
Edit: Do you know if I'll need to bottom tap for ARPs or just chase the threads?


I'm at the point that I may very well not need them, however I know I'll feel better installing them. I would hate to go through the entire process only to have the head gasked blow later on. Provided that I don't break a stud, in your opinion, would you say studs hold more securely then stock bolts?


I re-torqued my used stock bolts to 125 (No o-rings yet) and 1 of them felt like it gave. I took it out and it looked ok but I was affraid to reinstall it. I ended up replacing that one with a new stock head bolt. I would feel a little concerned torquing old stockers past 125 (Call me chicken) unless perhaps they were all new but even then I would be a little worried to take them to 150 let along 180. I had no idea people were taking them to these torques. Are these people using stock bolts because it is far cheaper then studs or because they feel that they are better suited then stock bolts (ie. don't break like studs do on occasion)? Sorry for all the newbie questions... But I am in fact a newbie. :doh:
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just chase them
 
didnt somebody do the calculations on the strength of a stock head bolts........i have a very hard time believing they would survive at 180, and 150 sounds like a stretch to me
 
I'm not doubting these guys experiences but at 180 pounds it does seem like you would be doing more harm then good. At some point the bolt will simply yield and you will end up lowering clamping force. I don't see myself going past 125 on stock bolts, but then again I have been proven wrong many times before.
 
OrangeNV said:
didnt somebody do the calculations on the strength of a stock head bolts........i have a very hard time believing they would survive at 180, and 150 sounds like a stretch to me
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Stock is what? Torque to 90 ft lbs and then add 90°?

If you think about torquing a lug nut to 90 ft lbs then adding another 90°....I'd buy it.
 
IIRC when i did 90ftlbs+90* then checked the torque it was initially 120 fl lbs with my stock head bolts. I dont know if they rest and lose tension or not.
 
then why wouldnt they just say torque to 120 then? torque to 90lb then add 90 degrees, it just fishy to me
 
Big Blue24 said:
Most of the "pro" diesel shops in Georgia use stock head bolts torqued to 150+ for o-ringed heads.

I personally will only use stock headbolts, unless I was given a set of studs for free and I didn't have stock head bolts available!
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OrangeNV said:
150!:aiwebs_029::what:
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wideopen said:
Yep the Georgia crews have Stock Head Bolts torqued to 150lb's
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:)


Held 800+/- on an o-ring'd modded 24v HG for 5000+ miles... Until I had a Rod exit the Block on both sides!! :nail:
 
OrangeNV said:
didnt somebody do the calculations on the strength of a stock head bolts........i have a very hard time believing they would survive at 180, and 150 sounds like a stretch to me
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OrangeNV said:
then why wouldnt they just say torque to 120 then? torque to 90lb then add 90 degrees, it just fishy to me
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Look at any build that Jeff Garmon or Darren Morrison do.. In there own trucks....

Stock bolts...

Just sayin.....
 
I think there are other advantages to stock bolts (other than cost) that many don't talk about.


Small example, when trying to tie down a tarp for a cross county drive, what works better: high tensile nylon rope pulled as tight as you can get it, or a few lower strength bungee cords?

Although a bungee cord allows the tarp to move a little when a big gust of wind hits it, it still pulls back and keeps constant tension.

When a big gust of wind hits the load tied down with the nylon rope, the rope stretches just a hair and the tarp/load gets loose.


Before anyone else comments on the "ridiculous example", think about it for a minute, then flame me!
 
But if the bungee chord stretches and lets the tarp rip (headgasket) then the tarp is useless anyway. Thats just how i look at it.
 
For most people doing torque to yield bolts allows for a more accurate torque. The wrong lube, a torque wrench that is out of calibration, and a head gasket that compresses during initial heat cycles, makes torque to yield bolts a viable solution.

Advantages of studs are mainly in two areas. One, they have better thread engagement. More of the treads are used in the block, and a better pitch thread is used during tightening. Second, the studs are still in their elastic range. Once they have taken a "set" they do not deform as much when strain is exerted on them, and will return once the strain is removed.

To use the example of the bungie above (good analogy by the way), if you stretch the bungie to far or to often, it never comes back and holds the tarp as tightly as it first did. This would be an example of stretching beyond the yield point, where the fastner leaves the elastic range and enters the plastic range. When torqueing a "torque to yield" bolt, it is recommended that they only be used once. The reason is that the bolt has been tightened beyond it elastic range, into it's plastic range. Once a bolt has been tightened into the plastic range, it will not return back to it's original length, or strength.

Which is better? Either method can exceed the blocks ability to hold the fastener. Head bolts are cheap, but have a limited number of cycles they can be effectively used. Good quality studs can be reused many times as long as they are not torqued beyond the yield point. Once that happens they are no better then the bolts. Properly used studs can be make the blocks ability to hold the stud without cracking or pulling threads, better.

I use ARP studs. The standard on my 02, and the new age 625+'s on my 05. No problems with either.

Paul
 
Very informative Paulb. Thanks for taking the time to put that in simple enough words for some of us to understand.
 
I had sock bolts with 80 +psi and n20 and no head gasket issues. Put in a cam and did studs too and poped the gasket at 60 psi.....
 
Lostnwalmart said:
I had sock bolts with 80 +psi and n20 and no head gasket issues. Put in a cam and did studs too and poped the gasket at 60 psi.....
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So did you go back to stock bolts when you replaced the gasket? Do you think that perhaps nitrous and 80PSI could have compramised the gasket before the studs went in?
 
there is a very large dif between a properly torqued set of FRESH headbolts, and a stock set with a ton of miles on them..... keep that in mind.

i'm running A1's and have had no issues what so ever
 
TheSh111t said:
So did you go back to stock bolts when you replaced the gasket? Do you think that perhaps nitrous and 80PSI could have compramised the gasket before the studs went in?
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New gasket and I'm keeping the studs. Will be replacing itnthis weekend
 
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