ARP came out with a giant writeup about over torquing head studs. They are supposed to be torqued to 210. Torquing them to 280 can actually stretch your head studs as you put them in. Stick to the books because your going to be very sad when you blow another head gasket.

 

There's an interested thread on PSA about the torquing of the studs.

For a fact, ARP used to be 245 ft/lbs with the old lube. They came out with a new lube called ultra torque, that was supposed to eliminate scatter and allow for correct torque numbers on the first pass. The new lube requires 210 ft/lbs. I would highly suggest getting it. Jegs and summit carry it.

Now... the discussion is about whether or not 210 is sufficient. A lot of guys are still going anywhere from 240-260 ft/lbs, even with the new lube. Shawn Ellerton (pilots the 1000+ rwhp 6.0s) runs 250 as well. He said he even tried going to 300 ft/lbs once and snapped a stud.

Now, my problem is... I'm willing to be none of these guys have done the math to compare the yield strength of the stud. More is not always better, it can actually yield the material and in fact not hold as much clamping force despite going to a higher torque. I've asked these guys for proof or math or anything, and get no responses. I copied the link to the thread and emailed a contact at ARP to get his thoughts on the subject, and am awaiting that response.

I'll be doing my studs in the next week or so most likely and am still trying to figure out what torque value to go to. Even though those guys are just shooting from the hip and going with "more is better" there have been enough of them doing it without issues that it does have me thinking maybe I will go above the 210. Maybe somewhere in between? Maybe 235 ish? I don't know just yet.

 

My shot from the hip will prob be 235ish as well, I think the 210 is a bare minimum,


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Who do you think knows the proper strength of ARP studs? ARP or hipshooter
If you want to torque them down that high why don't you get their newer studs, the ones that cost about $1000 and I think the torque for those is around 275ft-lbs.
A proper retorque to original torque used should be all you need.The problems guys were having before were from not machining heads/Black Ox gaskets/ thinking because they had studs they didn't have to let it warm up before jumping on it/trying to tow 20k lbs on race tunes because they had an EGR delete and STUDS.... A little common sense goes a long way when it comes to combustion engines.

 

Bob, these are some pretty high output powerstroke shops doing this as well... it's not just one or two guys.

I agree though, ARP put that spec there for a reason, not as a bare minimum. They take the yield strength of the stud and calculate a torque value (in this case 210 ft/lbs) that will force a certain % of yield on the stud, so say they will go to 75% of the yield strength of the stud. Meaning if you cover that other 25% up, the stud is junk and permanently deformed, even if it doesn't' break. These are arbitrary numbers but you get the idea.

here's the link on PSA for some good reading...IDP, MPD, and Warren - a question for you - PowerStrokeArmy

 

Good read but no data as far as torque strength, if you over torque a fastener beyond the tolerance of the material then it will have less actual clamping force even though it was torqued higher.

 

Agreed, I'm on your side with that and I've pointed that out to those guys numerous times, as soon as I ask where the math is, everyone disappears. It's not like the math is proprietary at all... it just shows that they're all guessing at numbers too. Some of the shops have done some at 210 and had trucks come back, so they just go more and more.... I don't mind people thinking outside the box and doing something other than recommended, but prove it to me!

 

Just wondering how heavily modified the trucks with stud failures are and if the owners were going for the outer limits of performance? Old school is mod till something breaks , fix it better then break something else! Hope these issues are settled before I do mine! I'm more preventative on mild truck, but really want reliable power . . Curious to learn more.

 

I don't think any of us would have issues going to 210 like ARP recommends.

Another issue that a lot of people over look is the flatness of the block, most of us backyard mechanics are not taking the entire engine out of the block, disassembling everything and bringing the block to the machine shop either you know... so if you have a truck that was heavily modified and beat on pretty hard, it's possible the block surface is crap too. In which case, torquing beyond what ARP recommends wont help either.

I'm hoping to have the cab off of my truck this weekend, I'll let you guys know what torque value I decide to go with.