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ARP main stud instructions

Will L.

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@ak diesel driver asked about head bolt/ stud also, so added that for a couple more bucks. Glad I did because look at how much lower the arp clamps than the bolt on the head stud!
But the 10mm studs torqued at 50 as suggested by a few I think is mega overkill. The ARP guys I talked to before kinda freaked when I told them factory numbers and what the stud suggested one was. Now I get why.

The testing was done with a hallow cylinder with affected area of 7.22 square inches. So hydraulic psi x 7.22 = clamp force. There is minor variations in what oil is used, accuracies of torque wrench, and the person operating the tools and reading the gauge, but identical tools and conditions on all fasteners keeps it equal.
I used 2 different quality gauges, compared 3 different torque wrenches 2 of which were calibrated within the month and the 3rd was a bar torque wrench.
tests done in March of 2020, I got my first ASE Masters back in the 90’s- so proper technique was used.

I went through 4 main 10mm bolts, 4 12mm main bolts, 4 12mm head bolts, 2 10mm main studs, 2 12mm main studs, 2 12mm head studs. All tests were done twice.
Room for error in reading the pressure I would estimate as 5-10 psi, however any misreading was consistent in recording.

One of the gauges is calibrated in psi and force. The force listed on the spreadsheet is based on psi X 7.22 via excel formula.

Please everyone share this on other forums, Facebook, etc so anyone can use the ARP studs and can match the force applied from bolts so there is no added stress to block and not even require align bore. Or they can choose to exceed clamp force if building hot rod and can see to scale how much more force (stress) they are applying to the block.

ANYONE that sells stud kits is welcome to include this chart or duplicate information from this chart in your kits. Just remember ARP doesn’t acknowledge anyone selling 6.5 main stud kits, and I am not authorizing the selling either for legal purposes. I am only authorizing sharing the mathematical testing for comparison I did.
 

Will L.

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When my wife or son shows me how to email the spreadsheet, I will email it to myself and anyone interested. My computer skills are poor.

Something interesting is the head stud clamp force lower. Remember ARP did the testing and sells head studs and set the specs accordingly. My understanding is the TTY bolts clamp but yield, and if there is a cylinder over pressurization event the bolts already at yielding point will stretch. This lifts head, the gasket fails.
However the ARP studs have a failure (stretching point) far beyond that of the blocks capacity. So if you max the head studs to say 120ft lbs, the clamp for e equal to the highest point of the TTY bolt, that same over pressurization event will now either rip the threads from the block, or warp the block- as many have learned.

feel free to crank-em down. Just know the smaller increase of protecting the gasket comes at the risk of destroying the block.

I believe this is the same case with the main studs. Some of us have seen blocks with the threads ripped right out if the main webs. Some seen total web failure. I’ve said it before and will a hundred more times... I believe match the clamp force AT MOST. The way to extend block life (except serious high performance) is to lessen the stress in the weak by design main webs.
 

Will L.

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Oh yeah, I mic’e the rigging before and after. No deformities occured, other than the 10mm threads getting damaged when it was over torqued. And the cold roll tests harder than the block material. So block threads would fail before the test rig.
Again I forgot to take many pics along the way. Here was a couple.
76D1559D-C31D-4396-9E51-1DA5B1091763.jpeg583E769A-003E-4373-A474-0F71C1797CB6.jpegE2E185EB-FDF4-43DD-A53D-8B1568EB0FA6.jpeg7249CA03-41A9-46AA-A9E4-23289C91B34B.jpeg033C726B-8AC0-4C6B-9C1F-16C431665752.jpeg637E3D7F-8F0F-4AF3-AA94-F3D17AF89A13.jpeg
 

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