Magnum Hydraulic Lifter

How and Why it Works

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The Hydraulic Lifter is a small but vital factor in any successful effort to maximize engine performance and has gained acceptance due to it’s unique ability to increase engine efficiency, extend valve life and reduce maintenance.  Yet lifters are still a  mystery to many people who use them or could be using them.  This need not be the case.  Basically hydraulic lifters must do only two things; collapse very, very slowly and recover from the collapsed state very rapidly.

Some of the mystery surrounding lifters arises because we tend to confuse the actions of automotive shock absorbers with those of valve lifters.  While the principle is basically the same in both, the action is vastly different.  The hydraulic lifter has a very short cycle (less than 1/1000th of an inch in most cases) and returns to essentially the same place at the end of each cycle.  The hydraulic lifter, in order to function properly, must collapse very slowly.  So slowly, in fact, that it is impossible to detect its movement under ordinary circumstances.  The recovery rate, on the other hand, is very rapid and positive.

Another function of the slow collapse of the lifter is to accommodate the growth and shrinkage of the engine as it heats and cools.   This expansion and contraction happens in all engines but on large stationary engines it is much more pronounced.   As the hydraulic lifer collapses and recovers, with each cycle of the engine, the valves stem grows due to heat.  This growth creates pressure on the pushrod and the hydraulic lifter automatically adjust to the growth with less recovery to maintain a neutral position.   Once the engine is turned off, the metals cool and the hydraulic lifter recovers to it’s previous set length and is ready to run again as soon as needed.

Unfortunately, the manufacturers of hydraulic lifters have done little to dispel the aura of mystery surrounding these vital components.  Their efforts to adapt the concept of hydraulic lifters to the large stationary engines found throughout the chemical refining and gas transmission industries have resulted in various highly complex designs with all manner of sealing arrangements and methods of mounting.    Magnum Machine offers a clear understanding of what is going on in the engine and alternatives that are user and maintenance friendly.