10mm Head Stud Set, 12.7mm Longer Then Stock, Chromoly

OVERVIEW

When you''re pushing the limits of an air-cooled Volkswagen engine, the standard hardware simply isn''t enough to keep your cylinder heads sealed against the barrels. High-compression builds and high-horsepower turbo applications put immense strain on the engine case and head interface, often leading to "head lift" or catastrophic stud breakage. These EMPI 10mm Chromoly head studs are the definitive solution for builders who demand reliability under pressure. Manufactured from high-tensile 4140 chromoly steel, these studs offer significantly higher fatigue resistance and tensile strength compared to stock carbon steel bolts. By replacing your aging or weak factory studs with this precision-engineered set, you ensure that your combustion chamber stays sealed, preventing costly leaks and protecting your investment from the mechanical failure that frequently plagues performance Type 1 engines.

This specific set is designed for custom applications that require extra reach, featuring a 12.7mm (1/2 inch) increase in length over the standard factory dimensions. This extra length is critical when using aftermarket high-performance cylinder heads with thicker flanges, or when utilizing head spacers to adjust deck height and compression ratios. The kit is comprehensive, including all necessary hardened washers and nuts to complete the installation. Furthermore, EMPI has accounted for the unique requirements of the "late style" dual-relief cases by including the specific long stud required for the oil cooler area. Whether you are building a weekend drag racer, a high-revving street sleeper, or a heavy-duty off-road rail, these +12.7mm chromoly studs provide the clamping force and structural integrity needed to keep your VW engine running cool and tight.

FITMENT

This head stud set is designed for Volkswagen Type 1 based engines utilizing 10mm thread engine cases. Please verify your case thread size before ordering, as many later factory engines transitioned to 8mm studs.

• Volkswagen Beetle: All years utilizing 10mm case threads.
• Volkswagen Karmann Ghia: All years utilizing 10mm case threads.
• Volkswagen Bus / Type 2: 1950-1971 (1200cc, 1300cc, 1500cc, and 1600cc upright engines).
• Volkswagen Thing / Type 181: All years with 10mm case threads.
• Aftermarket Cases: Compatible with AS41 and AS21 performance cases tapped for 10mm studs.
• Custom Builds: Ideal for engines using thick-flange performance heads or cylinder spacers.

SPECS

• Material: High-Strength 4140 Chromoly Steel.
• Diameter: 10mm.
• Length: +12.7mm (1/2 inch) longer than stock factory length.
• Finish: Black Oxide for corrosion resistance.
• Quantity: Full set of 16 studs.
• Hardware Included: 16 High-strength nuts and 16 hardened washers.
• Special Feature: Includes the specific "long stud" for late-model dual-relief cases.
• Tensile Strength: Significantly exceeds OEM Grade 8 specifications.

PRO TIPS

Tip 1: Ensure Proper Case Engagement and Thread Cleanliness. Before installing your new chromoly studs, it is vital to "chase" the threads in the engine case with a 10mm tap. Even a small amount of debris or old sealant can cause the stud to bind, leading to inaccurate torque readings or even cracking the case webbing. When installing the studs into the case, use a small amount of high-quality thread locker or sealant on the case-end threads to prevent oil migration. Screw them in until they bottom out, then back them off a quarter-turn to ensure they aren''t putting "point pressure" on the bottom of the casting, which can lead to stress fractures.

Tip 2: Accounting for the Extra Length. Since these studs are 12.7mm longer than stock, you must dry-fit your cylinder heads and rockers before final assembly. Check for interference between the ends of the studs and your rocker arm assembly or valve covers. In some performance heads, the extra length may require the use of deeper valve covers or clearancing of the rocker stands. Always verify that the nut has full thread engagement and that you aren''t "bottoming out" the nut on the unthreaded shoulder of the stud, which would prevent proper clamping force on the head.

Tip 3: The Multi-Stage Torque Sequence. Chromoly studs have different expansion rates than the aluminum or magnesium case and the aluminum heads. To get a perfect seal, always torque the heads in at least three progressive stages (e.g., 10ft/lbs, 18ft/lbs, and finally 23-25ft/lbs depending on your specific engine builder''s recommendations). Follow the factory "criss-cross" pattern religiously. It is also a "best practice" to re-torque the heads after the first heat cycle. Let the engine cool completely to room temperature before checking the torque, as checking them while hot will give you a false reading and could potentially pull the threads out of a warm case.