A hydraulic lifter, also known as a hydraulic tappet or a hydraulic lash adjuster, is a device for maintaining zero valve clearance in an internal combustion engine. Conventional means of adjusting valve actuation always require a small clearance to be left between the valve and its rocker or cam follower to allow for thermal expansion and wear, as it is vital that a valve must never be prevented from closing completely; this rapidly burns it away, especially in the case of the exhaust valve. The hydraulic lifter was designed to ensure that the valvetrain always operates with zero clearance, leading to quieter operation and eliminating the need for periodic adjustment of valve clearance. In mechanical engineering, a tappet is a projection which imparts a linear motion to some other component within an assembly. ... Lash are an alternative/punk rock band from Perth, Australia. ...

The hydraulic lifter consists of a hollow expanding piston situated between the camshaft and valve, either operated by a rocker mechanism or, in the case of double overhead camshafts, directly by the camshaft. It is filled with engine oil intermittently from an oil gallery through a small drilling. When the engine valve is closed, the lifter is free to fill with oil, but when the valve is opening and the lifter is being operated on by the camshaft, the oil feed is blocked and the lifter acts just as a solid one would, oil being nearly incompressible.

Hydraulic lifters were popular on automobiles designed in the 1980s, but most newer cars have reverted to bucket-and-shim mechanical lifters. Although these do not run as quietly and are not maintenance-free, they are cheaper and rarely need adjustment because the wear caused by operation is spread over a large area. Karl Benzs Velo model (1894) - entered into the first automobile race An automobile (or motor car) is a wheeled passenger vehicle that carries its own motor. ... The examples and perspective in this article or section may not represent a worldwide view. ...

This is incorrect as most light vehicle engines in the last 10 years have been made in a Type II configuaration where an overhead cam actuates a Rocker Arm that in turn actuates a valve with the opposite rocker side of the rocker arm being supported by the Hyrdraulic lash adjuster element. Major produces of lash adjusters in the USA include Eaton, Delphi and INA, while of the three INA has the best explanations and models on their web site. Hydraulic lifters were first put into engines, in mass production, in the 1950's by General Motors. Since then Hyrdraulic Lifters have always been a mainstay in domestic engines. In other parts of the world where smaller engines are utilized the tendency was to stick with direct acting tappets however, again, in the past five to ten years the trend is changing towards hydraulic lifters (especially with Toyota). Only Ford is now considerding reverting back to the primitive Type I, direct acting technology but this is because they are desperate to take cost out of their engines in an ill fated attempt to regain profitability; their quality will suffer and consequently so will their market share.

There are a number of potential problems with hydraulic lifters. Frequently, the valvetrain rattles loudly on startup due to oil draining from the lifters when the vehicle is parked. This is not considered significant provided the noise disappears within a couple of minutes, although typically it usually only lasts a second or two. A rattle that does not go away can indicate a blocked oil feed or that one or more of the lifters has "collapsed" due to wear and is no longer opening its valve fully. The affected lifter should be replaced in the latter circumstances. In extremely rare circumstances, a lifter can "pump up" and create negative valve clearance so that its valve cannot close. This is more serious as burned valves will result. In all cases it is important to follow the manufacturer's recommendations for oil viscosity and quality. The pitch drop experiment at the University of Queensland. ...

Cars with hydraulic lifters include the first generation Mazda MX-5 and most General Motors models produced in the 1980s. The Mazda MX-5 (also known as Miata in North America and Roadster in Japan) is a sports car built by Mazda in Hiroshima, Japan, since 1989. ... General Motors Corporation, also known as GM, is the worlds largest automaker. ...

This is incorrect as most light vehicle engines in the last 10 years have been made in a Type II configuaration where an overhead cam actuates a Rocker Arm that in turn actuates a valve with the opposite rocker side of the rocker arm being supported by the Hyrdraulic lash adjuster element. Major produces of lash adjusters in the USA include Eaton, Delphi and INA, while of the three INA has the best explanations and models on their web site. Hydraulic lifters were first put into engines, in mass production, in the 1950's by General Motors. Since then Hyrdraulic Lifters have always been a mainstay in domestic engines. In other parts of the world where smaller engines are utilized the tendency was to stick with direct acting tappets however, again, in the past five to ten years the trend is changing towards hydraulic lifters (especially with Toyota). Only Ford is now considerding reverting back to the primitive Type I, direct acting technology but this is because they are desperate to take cost out of their engines in an ill fated attempt to regain profitability; their quality will suffer and consequently so will their market share.

To truly do justification to the history of the Hydraulic Lifter a person could write a 100 page technical paper easily. The person who wrote the above doesn't have accurate information about the topic and should not be allowed to write any more articles. Thanks.

I am an Engineer who works for one of the aforementioned producers and have been working in the design and production of Hyrdraulic Lifters for the past 15 years. It bothers me to see such inaccurate information on Wikipedia, an informaiton source that is becoming highly used by any and everybody.