025-109-451 VW Vanagon Valve Adjusting Screw - 1.9L M9x26x1.0 Each

Valve Adjusting Screw – 025-109-451

The 025-109-451 is a critical valvetrain component designed for the Volkswagen Vanagons 1.9L engine. This adjusting screw threads into the rocker arm and provides the contact point for the valve stem. Its primary function is to allow for the precise setting of valve clearance or "preload," which is essential for ensuring the valves open and close at the correct intervals and that the hydraulic lifters operate within their intended range.

In the high-heat environment of the Vanagon engine bay, these screws can experience wear on the contact tip or "mushrooming" over time, making accurate adjustments difficult. Replacing worn screws with the 025-109-451 ensures a smooth, flat contact surface, reducing valvetrain noise and preventing uneven wear on the valve stems. This part is vital for maintaining the efficiency and longevity for the 1.9L flat-four powerplants.

Detailed Vehicle Compatibility

VW Vanagon:

• 1983, 1984, 1985

Product Highlights & Features

• Hardened Steel Construction: Manufactured from high-strength steel to withstand constant high-frequency impacts without deforming.

• Precision Threads: Features clean, accurate threading for fine-tuned adjustments and a secure lock-nut fitment.

• Optimized Contact Tip: The base of the screw is specifically finished to provide a consistent contact patch against the valve stem, minimizing lateral stress.

Technical Specifications

• Part Number: 025-109-451

• Thread Size: M10 x 1.0

• Application: Rocker Arm Valve Adjustment

• Engine Type: 1.9L

• Quantity: Sold Each, 4 Need per Head, 8 per Vehicle

Installation & Maintenance Tips

• Inspect the Rocker Arm: When replacing the adjusting screw, always inspect the threads inside the rocker arm for damage. If the arm threads are stripped, the new screw will not hold its setting.

• Check the Valve Stem: Ensure the top of the valve stem is flat and free of pitting. A damaged valve stem will quickly wear down a brand-new adjusting screw.

• Preload Setting: For the Vanagon hydraulic lifter system, the standard adjustment procedure typically involves turning the screw 2 full turns in (clockwise) after the screw makes initial contact with the valve stem.

• Lock Nut Security: Always use a high-quality lock nut and ensure it is tightened firmly against the rocker arm. A loose adjusting screw can back out, leading to a dead cylinder and potential engine damage.

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