L-19 head studs showed up today!
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We just recieved the first 3 sets of l-19 head studs today and they look great!!! If anybody wants a set, we have another 27 sets on thier way and should be here by next tuesday.
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They are ARP L-19 studs. Just made out of a higher grade material that can withstand a higher tensile strength. Somewhere in the order of 240,000 PSI versus an ARP 2000 rated at 210,000 PSI (somewhere in there). Should lead to a stronger clamping force that's all.
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My intuition tells me that the threads in the (aluminum) block, not the tensile strength of the studs, limit clamping force. Please explain why this supposition is wrong.
Last edited by Gary Z; 04-29-2004 at 04:14 PM.
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The threads in the ls1 block with the 11 mm stud have a thread pullout at 150 psi.
The 11 mm stud in 190,00 psi 8740 has a 15,998 psi preload. With very high cyl pressure and the 4 bolt design, head warping causing head lifting is an issue. Its not the block that is giving out, its a combonation of weak cylinder heads without enough preload to hold them down. With the 260,000 L-19 you can increase the clamping force with a combonation of higher tourque psi and more yeild strength.
In about an hour i will have the "dyno sheet" from ARP with the yeild ft-lb and the preload with the L-19's.
The 11 mm stud in 190,00 psi 8740 has a 15,998 psi preload. With very high cyl pressure and the 4 bolt design, head warping causing head lifting is an issue. Its not the block that is giving out, its a combonation of weak cylinder heads without enough preload to hold them down. With the 260,000 L-19 you can increase the clamping force with a combonation of higher tourque psi and more yeild strength.
In about an hour i will have the "dyno sheet" from ARP with the yeild ft-lb and the preload with the L-19's.
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Are you saying that the stronger studs can be torqued higher than 70 ft-lbs without risking pull out? I notice that ARP says that recommended torque values are based upon 75% of the fasteners yield strength but that surprises me. In my experience, threads in aluminum are very fragile. I don't trust threads in aluminum and am very attentive to torque specifications.
Thanks, Gary
Thanks, Gary
Last edited by Gary Z; 04-29-2004 at 08:56 PM.
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The final numbers should be in the 90-95 range with moly.
You can torque a nut on a 11 mm stud in an aluminum LS1 block to 150 ft-lb before having to worry about the threads.
On another ls1 with 9/16 studs, we tourqed it to 140 lb ft without any thread pullout.
You can torque a nut on a 11 mm stud in an aluminum LS1 block to 150 ft-lb before having to worry about the threads.
On another ls1 with 9/16 studs, we tourqed it to 140 lb ft without any thread pullout.