ARP Crankcase Thru Bolt Kit

Multiple Porsche Fitments (204-5406)

Part #: 204-5406

Overview

The ARP Crankcase Thru Bolt Kit is a high-quality, precision-engineered fastener solution designed specifically for Porsche engines. Crafted to meet the demanding standards of professional engine builders and performance enthusiasts, this kit ensures your engine's main bolts are secured with maximum strength and reliability. Whether you're building a high-performance street engine or preparing a race-ready powerplant, these bolts provide the durability and precision fit needed for optimal engine integrity.

Designed for Porsche models with 2.0L and 2.7L engines, this bolt kit is an essential upgrade for those seeking enhanced engine reliability, improved fatigue resistance, and peace of mind during spirited driving or competitive racing. ARP's commitment to quality and engineering excellence makes this kit a trusted choice for Porsche owners who demand the best from their engine components.

Key Features

Designed with performance and durability in mind, the ARP Crankcase Thru Bolt Kit offers several key features that set it apart from standard fasteners:

• Manufactured from forged 8740 chrome moly steel, providing exceptional strength and fatigue resistance for demanding engine applications.
• Rolled threads after heat-treating significantly enhance fatigue strength—approximately 2000% better than bolts threaded prior to heat treatment—ensuring long-lasting reliability under high-stress conditions.
• Reduced wrenching head design allows for easier installation and removal, saving time during engine assembly or maintenance.
• Large underhead radius promotes even load distribution, reducing stress concentrations and potential bolt failure.
• Precisely engineered to fit Porsche 2.0L and 2.7L engines, ensuring a perfect, secure fit that maintains engine integrity.
• Engineered to meet or exceed OEM specifications, providing confidence in both performance and safety.
• Ideal for high-performance builds, race engines, or any application where engine reliability is critical.

Construction & Design

The ARP Crankcase Thru Bolt Kit is constructed from premium-grade 8740 chrome moly steel, a material renowned for its strength, toughness, and resistance to fatigue. The bolts are forged to ensure uniform grain structure and superior mechanical properties. After forging, the threads are rolled post-heat treatment, a process that enhances fatigue strength and ensures the bolts can withstand the rigors of high-performance engine operation.

The design features a reduced wrenching head, facilitating easier installation in tight engine bays or during complex assembly procedures. The large underhead radius distributes load evenly across the bolt surface, minimizing stress concentrations that could lead to failure. All components are precision-machined to exact specifications, ensuring a perfect fit and reliable clamping force.

Performance & Reliability

Engineered for performance, these bolts help secure your engine's main caps with maximum strength, reducing the risk of bolt stretch or failure under high RPM and power output. The rolled threads and high-grade material contribute to improved fatigue life, making them suitable for both daily driven and race engines. While they do not directly increase horsepower, their superior strength and reliability support consistent engine performance and longevity.

Installation & Fitment

The ARP Crankcase Thru Bolt Kit is designed as a direct bolt-on replacement for OEM main bolts on compatible Porsche engines. No cutting, drilling, or special modifications are required for installation. Proper torque specifications should be followed as per ARP instructions to ensure optimal clamping force and engine integrity. The kit is suitable for professional engine builders and experienced DIY enthusiasts alike, offering a straightforward upgrade that enhances engine durability.

• Easy to install with standard hand tools
• No additional modifications needed
• Designed for Porsche 2.0L and 2.7L engines

What's Included

• Complete set of main crankcase thru bolts
• Necessary hardware for installation
• Installation instructions

Ideal For

This bolt kit is perfect for Porsche enthusiasts, professional engine builders, and racers who demand maximum strength and reliability from their engine fasteners. It is especially recommended for high-performance builds, engine rebuilds, or any application where engine integrity under high stress is critical.

Emissions Note

This product is designed for off-road or racing use only and may not be legal for use on public roads in certain jurisdictions. Please check local regulations before installation.