Sr20 Redtop Head Torque Specs. FSM=87lbs ARP=65lbs Greddy=95.7lbs

[ImportIntelligence]

I am running a Greddy Headgasket, ( 1.2mm ) & ARP Head stud Kit. I have talked to ARP and they are saying to torque the head studs to 65ft/lbs of torque. I talked to Greddy and they say go 10% over stock torque. The FSM says to angle torque the bolts for a total of 87ft/lbs of torque on each bolt.

My questions are: What should the actual torque be with the ARP studs? Why would ARP studs require less torque than the OEM bolts? Streching??

On the ARP paperwork it says that the fasteners torque values that are listed are 75% of the fasteners yeild strength. Are the OEM bolts better?

BTW, ARP's phone hold music has a couple loose nuts.

-Matt[email protected]

[martin]

I am running a Greddy Headgasket, ( 1.2mm ) & ARP Head stud Kit. I have talked to ARP and they are saying to torque the head studs to 65ft/lbs of torque. I talked to Greddy and they say go 10% over stock torque. The FSM says to angle torque the bolts for a total of 87ft/lbs of torque on each bolt.

My questions are: What should the actual torque be with the ARP studs? Why would ARP studs require less torque than the OEM bolts? Streching??

On the ARP paperwork it says that the fasteners torque values that are listed are 75% of the fasteners yeild strength. Are the OEM bolts better?

BTW, ARP's phone hold music has a couple loose nuts.

-Matt[email protected]

Torque ARP bolts the way ARP recommends, and to teh ammount they specify. They should have a spec for using thei lube, and regular oil if I remember correctly.

Yes teh difference between stock bolts and ARP studs is due to the bolts stretching as they twis. Studs will stretch very slightly by comparison, and should not twist.

I'm really not explaining this very well... let's try again...With a bolt you are applying the clamping force by pulling everything together using the threads in the block. This results in friction on the head of the bolt , and teh threads in the block, plus twisting of teh bolt itself.

With a stud, it's already threaded into the threads in the block, you are applying the clamping force by screwing a nut on. There is less friction with the nut (compared to the stud), no (minimal ) twisting of the stud, and no (minimal) friction in the block threads.Which is why the torque required is less to get the correct clamping force.

The reason ARP usually provided two torque setting one for their lube, one for regular oil, is that their lube is ultra slippery and thus reduces the friction under the nut.

BTW.. some people like to loc-tite the studs into the block ARP don't recommend this.

I hope this helps.

-Martin.