External valve spring – Hahn & Sohn HDE20SS3-DW

The valve spring ensures that the valve closes reliably and on time back onto its seat after being opened by the camshaft — without a functioning spring, the valve would "float" and the engine would lose compression and power, and in extreme cases the valve could collide with the piston.

• This engine uses dual springs (outer and inner), which is a common design solution in higher-performance engines — the combination of two springs with different stiffness provides more stable valve operation at high engine speeds and a more even distribution of force than a single large spring. This part is the outer spring of the pair.
• The part is designed for the four-cylinder diesel engine WEICHAI WP2.3D25E200 (Hahn & Sohn HDE20SS3-DW generator, 20 kW / 25 kVA).

 WHY CUSTOMERS CHOOSE IT

• Exact match for the WEICHAI WP2.3D25E200 engine
• Essential part for a complete valve train overhaul

PRACTICAL TIP

When replacing the springs, always replace the outer and inner spring together as a pair at the given position, even if one of them appears visually undamaged — they are designed to work together with the specific stiffness of both springs, and combining an old and a new spring would disrupt the correct force acting on the valve.

KEY FEATURES

• Type: outer valve spring (part of a dual spring assembly)
• Material: steel (spring steel)
• Designed for engine: WEICHAI WP2.3D25E200
• Compatible generator: Hahn & Sohn HDE20SS3-DW (20 kW / 25 kVA)

USE / INSTALLATION / OPERATION

1. Remove the cylinder head and valve train according to the service procedure.
2. Using a suitable spring compressor, compress the springs, release the retaining clip, and remove the retainer, outer spring, and inner spring.
3. Before installing the new spring, visually check that it is not deformed, cracked, or corroded.
4. Install the inner and outer springs together, fit the retainer, and secure them with the retaining clip.

Installation requires a valve spring compressor and experience with valve train servicing.