ARP Head Studs Stretched On Me

[shockload]

so anyways i was putting an mls gasket and head studs on my new de engine and a few streached on 75 ft. lbs. i used them once before on another engine. what does everyone touque them to? needless to say i was ticked off . i pulled them out also and they are f*ck ed , the fine thread at the top on a few is now hour glass shaped to an extent. theres also the possibility that the tourque wrench i used is off but i had them tourqued to 90lbs before.

[Chezedik]

Mine are at 70lbs.

[PapaSmurf2k3]

damn man that sucks, Did you call whoever you bought them from and/or take pics and send them to ARP? Mine are torqued to 72 ft-lbs. I hope mine don't pull this ****e

[rotorimp]

Torque is ALLOT different on ARP's--go to the website. You do not torque the fasteners down to factory spec.!! The fact that it withstood 90 Foot pounds before is an attribute of the fastener. If you used the arp moly lube then the torque should have been around 50 foot pounds. the clamping force of 50 ft-lbs is greater than the clamping force of the factory bolts. 90% of the torque on a fastener is FRICTION only 10% is doing the work! With the ARP lube and design of the fastener you do not need to torque it down as much-- We have well over 400hp at the crank and 50 ft-lbs is holding just fine.

http://www.arp-bolts.com/Tech/TechInstall.html

[PapaSmurf2k3]

http://www.jgsturbo.com/arptrq.html

it states 60, there are your directions and everything courtesy of JGS.

[Chezedik]

I thought I remember AMS saying that when using them with the Cometic gasket that you would run them in the 60-70lb/ft to ensure sealing.

[nissanfanatic]

Mine stretched too at ~75ft/lbs.. All the SR guys torque to ~85ft/lbs.. Its weird that they are rated to hold 180,000psi tensile strength but can't hold up to the torque levels mentioned...

[KATwo40]

I torqued mine to 80lbs. No problems yet.

[WDRacing]

How many guys have actually had issues with the stock bolts? I've never used studs and have put out decent power on several vehicles. To include my 498WHP RB20...all stock hardware. Hardly seems worth the price if they stretch.

WD

[BoostFab]

even so, they're suposed to be extra hardened, it shouldn't be stretched like that. call up arp.

[nissanfanatic]

Having issues with stock headbolts right now.. I think I lifted the head again..

[Florida240sx]

My stock headbolts stretched when my cosmetic hg was installed. I was so pissed when I saw oil coming out my block... Had 3 headbolts stretched

[KATwo40]

It's my understanding that the stock KA bolts are one-time use, torque to yield bolts. One shot, throw away, get new ones.

[wild_maxx]

You can re-use ARP studs correct? I have a set of main's in my E motor that I wan't to use in my DE motor. I know the E head studs are different but the mains are the same.

[Chezedik]

They are, sort of. Many different parts companies have an interest in using the phrase torque to yield, and then selling new bolts every time. But in most cases you are told by the OEM to check it for deformation, and replace if the condition exists. So you do not always have to replace them.

[WDRacing]

Agreed, I reused the one for my RB20 and I they were also stretch to torque bolts. My point is this, unless you're making big number, like Nissanfanatic, you probably don't need the studs. I suppose with a built block you might as well. But other then that, I see no reason.

WD

[nissanfanatic]

Problem is, I stretched the ARPs too.. On my second headgasket failure, the headgasket was in good shape, except for the fact that the entire exhaust side was darkened AKA the exhaust side of the head lifted...

I think my next plan is to call ARP with just specs and have them custom make me a set of studs out of the strongest material they have. Along with a slight cleanup of the head surface, I should be good with another cometic..

[wild_maxx]

^^ were you using the 10mm or 11mm head studs?

[WDRacing]

On helicopters we use several torquing methods I think may assist in the head torque process. I used this method on my RB20 and ran 28lbs of boost and put down 498WHP.

Obviously the torque is done in increments. SO lets say the last torque is 70 ft lbs. I would torque the head in 3 steps, 25 ft lbs, then 50 and finally 70 ft lbs. But prior to the final torque the head and hardware should be allowed to cool. So let 15-30 minutes pass prior to the final torque.

We also have a 10 flight hour torque check, so for a KAT lets make it 200 miles or so. This 200 miles shouldn't be done at max boost for max power. Once the 200 miles has passed, recheck the torque at 65 not 70 ft lbs. If none of the bolts/nuts move, then we would call the torque check a pass. If one or more of the bolts move. We retorque all of the bolts to 70 ftlbs and recheck again in 200 miles.

Make sense? Any questions or comments?

WD

[nissanfanatic]

Yea that does make sense WD. I just always thought you never needed to retorque on Cometics. And the Fel pro I used before was a perma-torque that said it required no retorque. So I just never checked it.. Next time, I'm gonna do all that stuff...

I used 10mm..

[KATwo40]

Sounds like you need to upgrade to the 11mm studs, Nissanfanatic. Unfortantely, that means a tear down to bore the stud holes.

[WDRacing]

There is noway he should need 11mm studs though. At that point you might as well Oring the head as well.

WD

[Chezedik]

They are just Saturn Main Studs that are used. Don't they make them in a 2000 series?