ARP Head Studs – it is for good reason that virtually every top professional engine builder relies on ARP Pro Series head studs for their competition engines. Simply stated, there’s not a better stud setup on the market today.
For starters, ARP uses a premium grade 8740 alloy that is rated far superior to aircraft quality. Each stud is placed vertically in special racks and precisely heat-treated to 190,000 psi. This procedure ensures complete heat penetration and the results are far superior to those lesser quality studs from other manufacturers who just dump pieces in a basket and hope for the best.
Following heat treatment, each stud is centreless ground to make it as close to perfectly concentric as possible. This procedure involves about ten very slight cuts and results in an exceptionally straight part. Note that lesser quality studs are not even centreless ground, the material is thread rolled in bar stock form (mostly before heat treatment, when the material is easier to machine). Because ARP studs are manufactured to such exacting tolerances, you will note that gaskets and cylinder heads glide into position and are perfectly aligned.
ARP studs are thread rolled after heat treatment, which gives them about 2000% (that’s twenty times) better fatigue strength compared with studs that are threaded before heat-treat (a very common industry practice). It costs a lot more to do it this way because it’s tough on tooling, but the results are well worth the extra effort.
You won’t find a better quality stud on the market from any other source. Look for ARP stamped on each stud as your assurance of quality.
To ensure proper thread engagement and accurate torque readings, clean ALL threads in the block (ideally with a thread chaser or tap).
Clean and inspect all hardware before installation. Look for obvious defects or shipping damages, plus proper fit, length, and dimension.
Screw studs into the block “HAND TIGHT ONLY”. NOTE: LOCTITE MAY BE USED IF A PERMANENT MOUNTING OF THE STUDS IS PREFERRED. THE FASTENERS, HOWEVER, MUST BE TORQUED BEFORE THE LOCTITE SETTING UP.
Install the cylinder head and check for binding or misalignment.
Lubricate the stud threads, nuts, and washers with ARP ULTRA-TORQUE FASTENER ASSEMBLY LUBRICANT. Then install the washers and the nuts onto the studs and tighten them hand tight.
ARP recommends using the ARP ULTRA-TORQUE FASTENER ASSEMBLY LUBRICANT that is provided with each kit as opposed to engine oil. This is due to higher friction on the studs as well as inconsistencies in the clamping force of the fasteners when engine oil or other low-quality lubricants are used.
PRELOAD (TORQUE) RECOMMENDATIONS:
Following the manufacturers recommended torque sequence tighten the nuts in three equal steps to 60ft lbs with ARP ULTRA-TORQUE FASTENER ASSEMBLY LUBRICANT.