ARP Headstud Break-in?
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From: McKinney, TX
ARP Headstud Break-in?
I'm installing the ARP headstuds tomarrow and we were going to go to the track (1/4 mile) tomarrow night. Is it ok to go RIGHT after the install? I'll be pushing 27-28 lbs of boost.
When you torque the studs, make sure you cycle torque each stud at least five times. According to ARP if you fail to do this you won't break in the fastener threads and as a result the clamping force at 85lb-ft of torque won't be what it should be. Basically you have to tighten, loosen & tighten for five cycles until you finally set the torque. You'll feel a big difference in the amount of angle on the wrench required to reach desired torque when you follow their procedure.
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From: McKinney, TX
Originally Posted by bolsen
Yea, and retorque after one heat cycle
Originally Posted by propellerhead
When you torque the studs, make sure you cycle torque each stud at least five times. According to ARP if you fail to do this you won't break in the fastener threads and as a result the clamping force at 85lb-ft of torque won't be what it should be. Basically you have to tighten, loosen & tighten for five cycles until you finally set the torque. You'll feel a big difference in the amount of angle on the wrench required to reach desired torque when you follow their procedure.
Tgihten and loosen
I don't think you should be doing that.I remove each bolt and torque it to 75 and then drive the car for two days and then retorque to 85. I don't think you should be loosening and tightening the bolts.
I agree 100%. From my experience tightening and loosening is not good. Also, when you install and when you re-torque after a few days, allways make sure the block is cold (as in, hasn't been turned on for hours).
Good luck!
Good luck!
Originally Posted by GOKOU
Tgihten and loosen I don't think you should be doing that.
I remove each bolt and torque it to 75 and then drive the car for two days and then retorque to 85. I don't think you should be loosening and tightening the bolts.
I don't think you should be doing that.I remove each bolt and torque it to 75 and then drive the car for two days and then retorque to 85. I don't think you should be loosening and tightening the bolts.
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I know that all this torque, retorque, take it out and shout at it and then retorque it again is good with composite head gaskets but its been stated that it wasn't necessary with a metal head gasket because there is nothing to yield.
Anyone have a good explanation?
Anyone have a good explanation?
Originally Posted by GOKOU
Tgihten and loosen I don't think you should be doing that.
I don't think you should be doing that.--Dan
Mach V
MachEVO.com
Originally Posted by tke_413
BUT.....can I install them and then go straight to the 1/4 mile and run 28psi?
--Dan
Mach V
MachEVO.com
Read the documentation from ARP and then decide for yourself. it's a compelling arguement...
http://www.arp-bolts.com/pages/tech/images/fasttorq.pdf
Note, we cannot measure stretch with our Evo application so that leaves us with using torque to achieve preload. AFAIK, gasket construction has no bearing on recommended torque values.
http://www.arp-bolts.com/pages/tech/images/fasttorq.pdf
Originally Posted by www.arp-bolts.com
Friction is an extremely challenging problem because it is so variable and difficult to control. The best way to avoid the pitfalls of friction is by using the stretch method. This way preload is controlled and independent of friction. Each time the bolt is torqued and loosened, the friction factor gets smaller. Eventually the friction levels out and becomes constant for all following repetitions.
Therefore, when installing a new bolt where the stretch method can not be used, the bolt should be tightened and loosened several times before final torque. The number of cycles depends on the lubricant. When using ARP® recommended lubes, five loosening and tightening cycles is enough. This will “break in” the threads sufficiently.
Therefore, when installing a new bolt where the stretch method can not be used, the bolt should be tightened and loosened several times before final torque. The number of cycles depends on the lubricant. When using ARP® recommended lubes, five loosening and tightening cycles is enough. This will “break in” the threads sufficiently.
Last edited by propellerhead; Aug 11, 2005 at 02:03 PM.
omg...I'm so confused and scared after reading this thread.
I installed my ARP studs first with an allen wrench and tightened them as much as I could with my fingers. I used a box wrench to tighten the allen key a bit more.
I used the ARP moly lube on the washer, the stud and the nut. I torqued the nut to 75lb ft and then double checked after I put in the last stud that they were all at atleast 75lb ft.
Did I do this correctly?
I will retorque them this weekend (6 days since I installed them). Is this too long of a wait? Otherwise I could try doing it tonight...
Do I need to completely remove the stud to retorque them? Do I just need to remove the nut and retorque it 5 times?
I installed my ARP studs first with an allen wrench and tightened them as much as I could with my fingers. I used a box wrench to tighten the allen key a bit more.
I used the ARP moly lube on the washer, the stud and the nut. I torqued the nut to 75lb ft and then double checked after I put in the last stud that they were all at atleast 75lb ft.
Did I do this correctly?
I will retorque them this weekend (6 days since I installed them). Is this too long of a wait? Otherwise I could try doing it tonight...
Do I need to completely remove the stud to retorque them? Do I just need to remove the nut and retorque it 5 times?
Can BR, Pruven, or AMS or any performance shop chime in on this loosening and tightening thing? I like to know since I did not do that and believe the how-to-install did not state that as well.
Originally Posted by GOKOU
Can BR, Pruven, or AMS or any performance shop chime in on this loosening and tightening thing? I like to know since I did not do that and believe the how-to-install did not state that as well.
I can tell you that after following the procedure described by them that the torque wrench swings much more smoothly until it clicks.
Let me make myself clear. I didn't FULLY tighten the nut for each cycle. I swung the wrench back and forth 5 or 6 times as recommended, just not to 85lb-ft. I can tell you the action becomes much more smooth after you've done this.
Additionally, ARP says you can re-use their rod bolt and studs. So if they're safe to reuse then it should be safe to break in the threads before final torque, right?