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The reason for offering replacement studs stems from the fact that our testing found that no available head stud was compatible with our Nickies or any aluminum cylinders for that matter, with exception of the 911's equipped with aluminum cylinders from the factory. In most cases, the factory head studs are unable to perform satisfactorily under the increased expansion of an aluminum cylinder, in most cases leading to head leaks and fastener fatigue. On 911's, certain models came with dilivar head studs, which were designed to match the expansion of the cylinders, but also suffered from hydrogen embrittlement, which is a condition that results from the accumulation of hydrogen gas in the atomic structure of the metal. This gas flows to the point of high stress (stress risers) and causes microscopic cracks. The hydrogen then flows to the “new” crack tip and causes it to crack further. In this way the crack moves across the part, because the crack-tip IS the stress riser. Finally the crack gets so large that the section is not large enough to support the load. Hydrogen embrittlement can take place without tensile stress. ARP® employs a baking process that purges hydrogen gas from the steel, eliminating this problem. Used or old-style Dilivar head studs should be replaced and are not recommended for use with Nickies cylinders. It may be adviseable to use newer epoxy coated Dilivar studs on mag case engines if and only when exceeding 35 HP per cylinder. Only ARP's head studs are proven and tested for a lifetime of reliability and performance. In lieu of flame ringing your heads and cylinders on the 911 in turbo applications, a set of ARP head studs along with our Nickies cylinders is more than sufficient for up to 1 Bar of boost in most cases.
Our VW Type 1 ARP head studs are 10mm - we do not offer an 8mm stud. The VW Type 4 ARP head stud is a direct replacement for the factory head stud, as is the Porsche 356 and 912 ARP head studs. Where applicable, 12-pt hardware, including nuts, washers, and ARP lube are included. Our Porsche 356 and 912 ARP head studs are designed to be used with factory fasteners. We also offer a wide array of case through bolts, connecting rod bolts, and other fasteners manufactured by ARP for Porsche and VW.
Effective November 15th, 2007, ARP Hardware is now available without purchase of Nickies cylinders.
Contact us at 815-472-2939 or info@LNengineering.com to bring your “tried and true" Aircooled engine to the new standard of precision performance!
Website
last updated November 15, 2007. Contact webmaster at
info@LNengineering.com
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The
proprietary ARP materials used to make our
VW and Porsche head studs, thru-bolts, and connecting
rod bolts is about 33% stronger than the stock material, with a 220,000psi tensile strength and
improved fatigue characteristics. Our 911 head studs have a 265,000+ psi tensile strength. All ARP studs have been designed and tested for use with Nickies
Cylinders!
2008 Pricing Schedule
All LN Engineering Products are Proudly 100% Made in the USA!