Stainless Intake & Exhaust Valve, 40mm, Sold Each

OVERVIEW

When you are pushing the limits of your air-cooled VW engine, the valvetrain is the last place you want to cut corners. These 40mm stainless steel valves are engineered for the high-heat, high-RPM environment of performance Type 1, Type 2, and Type 3 builds. Unlike stock two-piece valves that are prone to head separation under extreme stress, these are forged from a single piece of premium stainless steel. This one-piece design ensures unparalleled structural integrity, while the swirl-polished head optimizes airflow into or out of the combustion chamber. Whether you are building a street-burning 1914cc or a high-revving race engine, these valves provide the durability and flow characteristics required to maximize your horsepower potential and ensure your engine breathes with maximum efficiency.

One of the biggest killers of performance valves is "mushrooming" at the stem tip caused by high-pressure rocker arms and high-lift camshafts. These IAP valves solve that issue with an exclusive alloy hard tip that is specifically designed to resist wear and maintain correct valve lash settings longer than standard valves. The stainless steel material itself offers superior resistance to corrosion and heat-scaling, which is critical for exhaust valves that endure the brunt of combustion temperatures. By choosing these valves, you are investing in a component that not only improves volumetric efficiency but also protects your cylinder heads from catastrophic failure. Sold individually, they allow for precise customization of your head work, ensuring that every cylinder receives the exact flow and protection it deserves for a long-lasting, high-performance life.

FITMENT

These 40mm valves are designed for performance-modified cylinder heads (such as 044, Street Special, or custom ported heads) for the following air-cooled Volkswagen models:

• Volkswagen Beetle: All years and models with performance Type 1 engine builds.
• Volkswagen Karmann Ghia: All years with performance Type 1 engine upgrades.
• Volkswagen Bus / Type 2: 1950 through 1971 (1200cc, 1300cc, 1500cc, and 1600cc based engines).
• Volkswagen Type 3: Squareback, Fastback, and Notchback models with performance engine configurations.
• Volkswagen Thing / Type 181: All years using Type 1 performance heads.
• Custom Applications: Ideal for Dune Buggies, Sand Rails, and Trikes utilizing air-cooled VW powerplants.

SPECS

• Head Diameter: 40mm (High-performance upgrade size).
• Material: One-piece forged stainless steel for maximum heat resistance and strength.
• Stem Diameter: Standard 8mm (compatible with standard performance valve guides).
• Finish: Precision machined with a swirl-polished head for improved intake and exhaust flow.
• Tip Construction: Exclusive alloy hard tip to prevent stem mushrooming and premature wear.
• Application: Suitable for both intake and exhaust positions.
• Quantity: Sold each (ensure you order the total number required for your head configuration).
• Compatibility: Works with standard or performance 8mm valve keepers and retainers.

PRO TIPS

1. Always Verify Valve Guide Clearance

When installing new stainless steel valves, it is absolutely critical to check the clearance between the valve stem and the valve guide. Stainless steel has a different expansion rate than standard carbon steel valves when it reaches operating temperature. If your guides are too tight, the valve can gall or seize, leading to catastrophic engine failure. For performance applications, we generally recommend a slightly looser clearance than a stock street engine to account for the increased heat of a high-compression or turbocharged build. Always use a high-quality assembly lube on the stems during the initial installation to ensure protection during the first critical moments of engine start-up.

2. Perform a Precision Valve Lap

Even though these valves are precision machined, they must be "lapped" into your specific valve seats to ensure a perfect 360-degree airtight seal. Use a fine-grit valve grinding compound and a hand-lapping tool to create a consistent, dull-grey ring on both the valve face and the seat. This process not only ensures maximum compression but also aids in heat transfer from the valve head to the cylinder head through the seat. After lapping, clean the valves and heads meticulously with a solvent to ensure no grinding compound remains, as even a tiny amount of leftover grit can cause rapid wear on the valve stems and guides once the engine is running.

3. Match with High-Performance Springs and Retainers

If you are upgrading to 40mm valves, you are likely building an engine intended for higher RPMs or increased power. Do not pair these high-quality stainless valves with weak, stock-style valve springs. To prevent "valve float" and ensure the valves close securely against the seat at high engine speeds, we recommend using heavy-duty single or dual valve springs and chromoly or titanium retainers. Since these valves feature a hardened tip, they are perfectly suited for use with high-lift rockers (1.25:1 or 1.4:1), but always double-check your rocker arm geometry to ensure the rocker is centered on the valve tip throughout its entire range of motion to prevent side-loading the valve stems.