ARP head stud nut OD
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Joined: Sep 2008
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From: Dayton, OH
ARP head stud nut OD I am looking for OD measurements of ARP stud nuts as I will be using them for my build. They may differ from bolt heads or not be a standard size.
Granted, the diameter of the nut is not a dimension that one is usually concerned with.
The heads I have chosen for my build have clearance holes for 1/2" studs. The block I am using is threaded for 8 mm studs. The nuts for 8 mm studs are smaller than those for 1/2" studs so there will be less contact area under the nut for an 8 mm stud vs that for a 1/2" stud. This will result in more force per SqIn applied to the cylinder head if they are both torqued to the same force. I am looking to calculate the differance in force.
Mostly it is an intellectual excercise and I will have the block tapped for 1/2" studs but as an engineer (although electrical) these sort of things interest me.
Thanks!
Granted, the diameter of the nut is not a dimension that one is usually concerned with.
The heads I have chosen for my build have clearance holes for 1/2" studs. The block I am using is threaded for 8 mm studs. The nuts for 8 mm studs are smaller than those for 1/2" studs so there will be less contact area under the nut for an 8 mm stud vs that for a 1/2" stud. This will result in more force per SqIn applied to the cylinder head if they are both torqued to the same force. I am looking to calculate the differance in force.
Mostly it is an intellectual excercise and I will have the block tapped for 1/2" studs but as an engineer (although electrical) these sort of things interest me.
Thanks!
I think the OEM studs are 11mm and the 8 mm are the small ones that go on the top. The 1/2 studs are for heads with a thicker deck I assume you have Brodix or other type of head like that. The c6 ZR1 Corvette uses a 12mm head bolt and the head from GM has thicker deck surface. You really only need the 1/2 stud with a blower/turbo or a very high hp motor as most of them just use the 6 bolt head with the 11 mm stud but ARP stud actually uses a 11mm on one end and a 7/16 on the other end. Are you saying that the 8 mm holes were punched out to 1/2 inch why would they do that they are not or is the block designed for 1/2 stud in the 8 mm holes in top of block.
ARP heads studs use washers under the nut. The washer is larger O.D. Torque spec for small studs has nothing to do with what studs you use elsewhere. Follow the published instructions.
I'm guessing about this next part, but I don't think the small studs are much for structural purposes, mostly there to promote a good gasket seal.
I'm guessing about this next part, but I don't think the small studs are much for structural purposes, mostly there to promote a good gasket seal.
Last edited by QwkTrip; Sep 13, 2022 at 06:24 PM.
Looking at an LS block I am not sure there is enough aluminum to support a 1/2 inch stud (and the 110 foot pounds of torque that goes with it) where the 8 mm bolts go on top ridge there. Now if sticking with the 8mm stud but need the larger washer ARP may have something or even the hardware store sells the case hardened washers that have a little more surface area like you were looking for.
