Hydraulic valve lifter

A device that eliminates the need for mechanical clearance in the valve train of internal combustion engines. Clearance is normally required to prevent the valve's being held open and destroyed as the valve train undergoes thermal expansion. However, clearance requires frequent adjustment and is responsible for much operating noise. The hydraulic lifter is a telescoping compression strut in the linkage between cam and valve, consisting of a piston and cylinder (see illustration). When no opening load exists, a weak spring moves the piston, extending the strut and eliminating any clearance. This action sucks oil into the cylinder past a check valve. The trapped oil transmits the valve-opening forces with little deflection. A slight leakage of oil during lift shortens the strut, assuring valve closure. The leakage oil is replaced as the spring again extends the strut at no load.

References in periodicals archive

In addition to combustion cylinder work, Tomadur also uses a Flex Hone tool to create a blended radius on hydraulic valve lifter bores, thereby avoiding scuffing problems on valve lifters.

Ball-style hone can be key to remanufacturing arsenal

Another business unit, hydraulic valve lifter manufacturer Precision Engine Products Corp., had long been separate in the corporate structure.

Stanadyne restructures to meet challenges

Service Bulletin SB-97-6A, issued in 1997, calls for removing and discarding hydraulic valve lifters. Shops have been tossing the used parts into the trash for years.

TCM's lifter crisis: reclaimed parts rule: the lowly valve lifter used to be the first thing tossed during overhaul. Now, reusable parts are a hot item

These include an aluminum block with cast-iron cylinder liners for extended service life; maintenance-free hydraulic valve lifters designed to ensure full power over the life of the engine; larger sleeve bearings on both the flywheel and PTO side designed to accommodate heavy loads; a heavy-duty air cleaner with integrated rain cap; and an integrated oil cooler mounted under the cylinder access cover, designed to provide improved cooling while still maintaining a compact profile.

Kicking it up a notch: Kohler's Command Pro now available with 40 hp rating; more Courage engines for consumers

To effect deactivation, there are special two-stage hydraulic valve lifters that have both inner and outer bodies.

The powertrain scene circa today [with a glimpse at the not-too-distant tomorrow]: in which Peter Brown of Ricardo--an engineering consultancy that's worked on projects from the Hummer H2 to the HEMI to powertrains that they've taken a vow of silence regarding--talks about what's going on under the hoods

The seamless shifts occur through the activation of two-stage hydraulic valve lifters. In normal mode, the inner and outer lifter sleeves are held together by a pro.

Power launch: three new GM powertrains offer more power and showcase Displacement on Demand and variable valve timing technologies

And hydraulic valve lifters require no maintenance.

Quiet-running lift trucks feature ergonomic design, four power options

We also included items like a nylon cam gear, hydraulic valve lifters that reduce the clanging of valves.

More than mere muscle: Kohler's new Command Pro engines deliver bigger power, but also put a premium on serviceability

Other features of the powertrain include hydraulic valve lifters, a Bosch alternator and electronic fuel injection speed governing.

Power to howl: MER Equipment introduces Savage Beagles marine generator set series covering five models ranging from 20 to 45 kW

The engine has hydraulic valve lifters, Cull pressure lubrication with oil cooler and a Nelson heavy-duty air cleaner.

Saws designed to cut out the wait

The Aegis engines, which were initially developed from the platform of Kohler's Command engine line, incorporate a range of premium features, including overhead valve technology, a full pressure lubrication system with a full-flow, spin-on oil filter; a 12 V, solenoid-shift starter; hydraulic valve lifters; an aluminum block with cast iron cylinder liners.

Kohler expands top end of Aegis engine line