Powertrain Systems

Delphi Hydraulic Lash Adjusters are used in internal combustion engines with overhead cam valve train systems. They support the pivot ends of the rocker arms while automatically controlling rocker arm positions to keep them in contact with the camshafts and valves. The range of the hydraulic lash adjuster accommodates engine build tolerances so that adjustment is not required during engine assembly. It also compensates for variation that occurs during the life of the engine so that additional service is not required. Hydraulic Lash Adjusters also provide lubricating oil for overhead components such as the cam/rocker arm interface and the rocker arm/valve tip interface.

The Delphi 21.4 mm Hydraulic Adjusters' proven design is well suited to two-valve overhead cam engines with heavier valves and higher loads and that do not require a more compact design.

Benefits

• No adjustment required at engine assembly.
• No adjustment required while in service. (The only service required is normal oil changes.)
• Metered overhead oil lubrication to the rocker arm interfaces helps provide improved engine durability.

Typical Applications

Delphi 21.4 mm Hydraulic Adjusters are engineered to meet the needs of end pivot rocker arm valve train systems where the packaging space of a typical single overhead cam valve train design is available. They can be used in gasoline, diesel and alternative fuel applications.

Specifications and Installation Guidelines

Installation Diagram

This illustration shows the typical installation and position of a Delphi 21.4 mm Hydraulic Lash Adjuster in the cylinder supporting the rocker arm. 

Performance Advantages

Delphi's 21.4 mm Hydraulic Lash Adjusters provide:

• High valve train speed capability enabling engines to exceed 7,000 rpm from high hydraulic stiffness design. This results in better dynamic control of the valve train at high speeds, where inertial loads and vibration amplitudes are higher.
• Optimization for minimal potential cold start noise. The oil reservoir and oil flow capability are optimized.
• Hardened steel plunger and body to enable life-of-engine durability.
• Chrome alloy ball check valve to reduce potential for sticking and the effects of contamination.

Delphi 21.4 mm Hydraulic Lash Adjusters have been in production for more than 40 years and have been used by engine manufacturers on five continents.

Delphi relies on its global capabilities, consistent processes and extensive testing to develop and manufacture hydraulic valve adjusters. The result is that Delphi provides customers with robust, reliable products and world class quality.

The Delphi Advantage

Delphi has more than 75 years' experience in valve train systems and our high-quality conventional valve train products have earned industry-wide respect. Delphi's deep understanding of the combustion process and its vast research and development capabilities have also enabled continuing innovation. Delphi is an industry leader in engine management systems, so whether a customer chooses a complete system or an individual component, Delphi's systems expertise is built into every product and it can help manufacturers achieve higher levels of performance and regulatory compliance.