Obtaining the optimum cylinder head-to-block sealing is especially critical in small displacement engines like the MINI, whether you are building high compression natually aspirated One / Cooper engine, or for your mild Cooper S supercharged engine to that all out no bars turbo /nitrous engine. That's why ARP® head studs are popular among leading MINI racers.
You should know that ARP® uses a premium grade 8740 alloy that is rated far superior to "aircraft" quality. Then, each stud is precisely heat-treated to 200,000 psi. Following heattreat, each stud is centerless 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. 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.
ARP® studs are thread rolled after heat-treat, which gives them about 1000% (that's ten times) better fatigue strength than those studs that are threaded prior to heat-treat.
You will also note that ARP® offers specially undercut studs for several engines. This procedure (done only to the shorter studs) more equalizes the "stretch" of both studs, which makes for a more consistent clamping force—one that compensates for head gasket compression when the head is installed. This helps prevent blown head gaskets, and assures optimum sealing!
Premium parallel ground washers are also included with each kit.
INSTALLATION METHOD FOR HEAD STUD KITS
Part Number: 201-4301 Application: BMW 1.6L (W10/W11) Mini Cooper
1. Always verify the part number for your application with the part number on the side of box and the part number on the instruction sheet. This will help ensure you have the correct installation procedure for your specific application before installing any components.
2. Clean and inspect all hardware prior to installation. Look for obvious defects or shipping damages, plus proper fit, length and dimension.
3. To ensure proper thread engagement and accurate torque readings, clean ALL threads in the block. Chase if necessary with ARP Thread Chaser, part number 912-0003 (M10 X 1.5).
4. If the cylinder head studs protrude into a water jacket, lubricate the block threads of the studs with ARP THREAD SEALER.
5. 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 PRIOR TO THE LOCTITE SETTING UP.
6. Install the cylinder head(s) and check for binding or misalignment.
7. 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 motor oil. This is due to higher friction on the studs as well as inconsistencies in the clamping force of the fasteners when motor oil or other low quality lubricants are used.
PRELOAD (TORQUE) RECOMMENDATIONS
8. Following the manufacturers recommended torque sequence tighten the nuts in three equal steps to 65 ft lbs with ARP ULTRA-TORQUE FASTENER ASSEMBLY LUBRICANT.
Note: ARP Ultra-Torque Fastener Assembly Lubricant has been specifically designed to reduce tension preload scatter and eliminate the need to cycle high performance engine fasteners before final installation. ARP Ultra-Torque far surpasses all requirements offered by previous ARP lubricants in terms of fastener preload repeatability and performance lubricating properties.