Name: ARP 260-4701 head studs Subaru Impreza EJ20 & EJ25 DOHC WRX/STi ARP 260-4701
Brand - ARP
Part Number - ARP-260-4701
Country of Manufacture – United States
It is for good reason that virtually every top professional engine builder relies on ARP Pro Series head studs for their all-out competition powerplants. Simply stated, there’s not a better stud setup
on the market today. ARP only uses premium grade 8740 alloy and a proprietary ARP2000 alloy that are rated far superior to “aircraft” quality alloy steels. Secondly, each stud is placed vertically
into special racks and precisely heat-treated to 190,000 psi for the 8740 material and 220,000 psi for the ARP2000 material. 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. It’s important to note that lesser quality studs are not even centerless ground – the material is thread rolled in bar stock form (mostly before heat-treat, when the material is
easier to machine). Because ARP studs are manufactured to such exacting tolerances, you will note that gaskets and cylinder heads literally glide into position and are perfectly aligned – something
that won’t happen with inferior quality head studs.
Using studs will make assemble an engine much easier (especially a racing powerplant which must
be serviced frequently and quickly!) with the cylinder head and gasket assured of proper alignment.
Studs also provide more accurate and consistent torqueloading. Here’s why. When you use bolts to secure the head, the fastener is actually being “twisted” while it’s being torquedto the proper reading. Accordingly, the bolt is reacting to two different forces simultaneously. A stud should be installed in a “relaxed” mode – never crank it in tightly using a jammed nut. If everything is right, the stud should be installed hand tight. Then, when applying torque to the nut, the stud will stretch
only on the vertical axis. Remember, an undercut shorter stud will have a rate similar to a longer, standard shank stud. This provides a more even clamping force on the head.
ARP ® - Automotive Racing Products are a manufacturer of fasteners/bolts found in engines and drivelines, ranging from OEM replacement parts to specialty hardware for racing applications. ARP is the world leader in fastener technology. These range from quality high performance OEM replacement parts to exotic specialty hardware for Formula 1, IndyCar, NASCAR and NHRA drag racing and marine applications.In order to ensure optimum quality control, ARP has grown to be exceptionally self-reliant and now controls all aspects of the manufacturing process. This is how ARP has been able to establish a reputation of top brand on the market.