ARP Head Stud Kit

2004–2006 Scion xA / xB 1NZ-FE Engine

203-4101

Overview:

The ARP 1NZFE Head Stud Kit is engineered specifically for the 2004 to 2006 Scion xA and xB models equipped with the 1NZ-FE engine. Designed for enthusiasts and professional tuners alike, this kit provides a reliable upgrade over the factory head bolts, ensuring superior clamping force and durability under high-stress conditions. Whether you are performing an engine rebuild, upgrading for forced induction, or seeking enhanced reliability, these head studs deliver consistent performance and peace of mind.

Manufactured by ARP, a leader in high-performance fasteners, this kit is ideal for those who demand precision and strength from their engine components. The studs help maintain proper head gasket sealing, reducing the risk of leaks and head gasket failure during aggressive driving or track use.

Key Features:

The ARP 1NZFE Head Stud Kit combines advanced materials and manufacturing techniques to provide exceptional strength and reliability. Key features include:

• Constructed from premium grade 8740 chromoly alloy, exceeding aircraft quality standards
• Heat-treated to an impressive tensile strength of 220,000 psi for maximum durability
• Centerless ground for exceptional straightness and concentricity, ensuring perfect alignment
• Thread rolled after heat treatment to increase fatigue strength by approximately 1000%
• Precision manufacturing tolerances allow gaskets and cylinder heads to slide into place smoothly
• Designed specifically for the 1NZ-FE engine to ensure perfect fit and function
• Pro Series ARP2000 studs known for superior performance in demanding applications
• Corrosion-resistant finish for long-lasting reliability

Construction & Design:

Each stud in this kit is crafted from ARP’s proprietary 8740 chromoly alloy, a material renowned for its strength and toughness. This alloy surpasses typical aircraft-grade fasteners, providing a robust foundation for high-performance engine builds. The studs undergo a precise heat treatment process to achieve a tensile strength of 220,000 psi, ensuring they can withstand extreme clamping forces without stretching or failing.

Following heat treatment, the studs are centerless ground to achieve near-perfect straightness and concentricity. This meticulous process involves multiple fine cuts, resulting in studs that allow for flawless alignment of the cylinder head and gasket. Additionally, the threads are rolled after heat treatment, significantly enhancing fatigue resistance and longevity compared to studs threaded before heat treatment.

Installation & Fitment:

The ARP 1NZFE Head Stud Kit is a direct fit replacement for the factory head bolts on 2004–2006 Scion xA and xB models with the 1NZ-FE engine. Installation requires standard engine disassembly to access the cylinder head. Due to the precision manufacturing and exact fitment, the studs facilitate easier assembly, allowing the cylinder head and gasket to slide into position smoothly without binding.

It is recommended to follow ARP’s installation guidelines, including the use of proper lubricants and torque specifications, to ensure optimal clamping force and reliability. This kit is suitable for both professional mechanics and experienced enthusiasts performing engine rebuilds or upgrades.

What's Included:

• Complete set of ARP Pro Series ARP2000 head studs for 1NZ-FE engine
• Installation instructions and torque specifications

Ideal For:

This head stud kit is perfect for Scion xA and xB owners looking to upgrade the reliability and strength of their 1NZ-FE engine’s cylinder head fasteners. It is especially beneficial for:

• Engine rebuilds and overhauls
• Performance enthusiasts upgrading for forced induction or higher boost levels
• Track and motorsport applications requiring enhanced durability
• Anyone seeking to prevent head gasket failure and improve engine longevity