I think the torque setting for the use of motor oil as a lube might have been closer to 100 IIRC, but I wouldn't go that high, Munky- Just use 80 with the lube, and if you find it leaks, you can always torque down more.
Helllppp
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I get yelled at when I post guesses in the tech section! People please post facts only. There is a number that I think I have seen, but I won't post it for this reason.
I have a question pertaining to the different torque specs though. Why does it matter what it is greased with? The bolts/studs don't have anything to do with the seal of the head. If you go too far, wouldn't you deform the aluminum head somewhat?
I have a question pertaining to the different torque specs though. Why does it matter what it is greased with? The bolts/studs don't have anything to do with the seal of the head. If you go too far, wouldn't you deform the aluminum head somewhat?
Munky;1262545 said:
Munky - The 120 ft/lbs is using motor oil for lube...if you do that with moly you will over torque to the point of stud failure (it's a 50% over torque - studs are designed to be torqued to 75% of yield strength). In addition, ARP publishes a max of 75 ft/lbs for use on an aluminum head for bolts due to the different thermal expansion differences between aluminum and steel. That restriction is not made for studs, but the problem still exists...the higher expansion of aluminum can exceed the yield strength of the fastener...if you over torque, it can easily cause failure. Read this and the "Torque wrench method" link on the left:
http://www.arp-bolts.com/Tech/TechInstall.html
Munky;1262718 said:
Just use moly for lube and go to 80 ft/lbs per the spec...that is plenty for a good seal. What you "buddy" did was in fact kinda stupid and doesn't mean squat...the "I did it, so it must be ok" method is not based on fact. Pay attention to the pre-load technique ARP recommends in the above link as well.
ForcedTorque;1262776 said:
Scott - You are dead on concerning "the facts"...if you not absolutely sure, don't post in the tech section.
Moly has a much lower friction coefficient than motor oil. That results in less resistance (friction) between the threads of a fastener and is the reason for the lower torque spec with moly. What you are after is clamping force...moly is much preferred because it produces that clamping force with less resistance for the torque wrench. Setting pre-load using the tightening/loosening cycle technique burnishes the threads and reduces friction even further...it results in the most accurate torque for the desired clamping force.
A gross over torque can deform the softer aluminum head. The real danger though is fastener failure under thermal expansion.
ForcedTorque said:
This is why:
"The friction coefficient of lubricants vary dramatically. Some are slicker than others."
^^^ The thorough explanation 
BTW - if you are going to use studs, I highly suggest you chase the block threads with a bottoming tap or thread chaser. As previously stated, the studs go into the block finger tight.
BTW - if you are going to use studs, I highly suggest you chase the block threads with a bottoming tap or thread chaser. As previously stated, the studs go into the block finger tight.
Why did you even bother to post a thread?Munky;1262718 said:
Just do what your genius friends does and continue to ignore the correct information people are posting.
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