Reply to thread

Message: [QUOTE="KCTurbos, post: 906530, member: 13852"] I digress and never should have stated that h11 don't EVER stretch... I just meant that they don't seem to stretch under our 6.0 powerstroke cylinder pressures while under high boost conditions people have reported that the arps do stretch. I can tell you from personal experience along with Jesse Warren that I have had trucks that only leak under really high boost and high cylinder pressures. That would mean that the studs are stretching. If the block or head was warped or the gaskets failed then it would leak even under low boost and low cylinder pressures. Also my post are not to try and prove anyone wrong or start any arguments. I am researching this exact issue and have been for a while trying to develop a better/easier/cheaper solution for the 6.0 guys that wanna push bigger power without having to wonder about their gaskets. Bouncing my thoughts off of people help out with creativity and research power. ^^^^ I am sorry my friend but this information is not correct. Higher tensile strength does not equal lower torque value. I can see why you would think this but let me help you out a little. h11 = 240,000 psi tensile strength torque to 185 arp = 220,000 psi tensile strenght torque to 215 625 arp = 250,000 tensile strength torque to 285 First off you can see that you must torque the standard ARPs down more than the h11 to achieve a lesser psi tensile strength. Yep that is right. You have a higher tensile strength with with less toqure which would appear to make your statement correct... but... the arp 625s are torqued down even more than either stud to achieve even more tensile strength. So what does that mean??? How can one be torqued more and the other be torqued less and acheive different tensile strengths. Well it is because the h11 steel stretches less to get the same clamping force. This means that they stretch less than the ARPs do. That is why you can torque them down less and get a higher tensile strength. The truth of the matter is the tensile strength does not change with how hard you torque down the bolts. "Tensile strength is indicated by the maxima of a stress-strain curve and, in general, indicates when necking will occur". Tensile strength is predetermined before you even put the stud in the truck. The tensile strength simply refers to how much force the metal can take before it yields and bottlenecks. There is so much more to the different types of materials being used than just the tensile strength... but I can tell you that simply by looking at the tensile strength and torque rating that arps stretch more than h11 or h13 tool steel Actually the main advantage is the higher tensile strength. But it also has to do with stretching. Think of it like this. Once you get the nuts nice and tight on the stud without applying any torque then the studs are all the same length and everything is flat and tight. Now once you start torquing down the nut you can actually see the threads starting to poke out above the nut... that is the stud stretching, not the head squishing... it will stretch the stud. Remember the torque reading you are getting not just the resistance of the stud stretching, it is also the friction. That is why ARP uses special lube. That is also why with the new ultra lube that they lowered the torque rating. The fact of the matter is you must stretch the arps farther than the h11s to get the same tensile strength/clamping force. That means for our application that the arps will stretch easier under the same load (actually stretch easier under less load). So if we are just talking about standard ARP vs H11 then you must stretch the stud farther and apply more torque to get 20,000psi less. This info seems to support the theory about why standard arps dont seem to hold up under high hp and high psi. This would also explain why some guys had nothing but problems with their standard arps and switched to h11s and all their issues went away (without doing anything different and no machine work) Some more food for thought... from what I have researched the standard TTY bolts had a tensile strength of 180,000 vs the 220,000 from the standard ARPs. Some people claim that the standard TTY bolts stretched and that is why a higher tensile strength was used. That is why the higher 220,000 tensile strength of ARPs helps not to blow gaskets. But in theory that extra tensile strength will only go so far before the studs start stretching again. How far exactly is anyone's guess but to say that the standard tty bolts will not hold up at all and then assume that the 40,000 extra psi tensile strength from the standard ARPs is an end all win all does not add up in my mind. That is why I think many guys above 550-650hp seem to have repeat failures with standard ARPs, especially with big vgt turbos that can build max boost at much lower rpms, pulling trucks that get abused, and anyone pushing 60+ psi through the motor. [/QUOTE]