How does lifters work with valves

As they wear, they self adjust. On a well maintained engine, hydraulic valve lifters will last well over , miles. They also run more quietly than solid lifters. But, eventually, they will wear out.

Valve lifters help to control the combustion process by letting fuel in, and exhaust out. When valve lifters wear out, your valves can't open or close properly.

This reduces the amount of power the engine can produce. When one of your valve lifters goes bad, one of the two scenarios can happen:. Either way, it throws off the engine's valve timing, and the engine won't run as well as it should.

The biggest telltale sign that you need a new valve lifter is a distinct noise coming from the engine. The noise is usually easiest to hear at idle. The best thing to do when one of your valve lifters fails is to replace it as soon as possible.

If you ignore the problem long enough, related engine parts will wear out faster. These parts include the:. If you believe that one or more of your valve lifters has gone bad, you don't have to take your Ford to a shop. You can replace them right at home! You'll save a lot of money on labor and replacement valve lifters.

We offer wholesale pricing for genuine OEM Ford valve lifters. Check out our catalog of genuine OEM Ford valve lifters. Look up your Ford model to get the right part numbers. It's important to note that it's a good idea to replace all of your valve lifters at once, even if one of them has gone bad. If one is bad, then chances are the rest will fail soon. You may be under the false assumption that a solid lifter camshaft makes more power than a hydraulic design.

That is not true in a pure sense. A solid lifter has the potential to follow a more aggressive camshaft lobe and also to work effectively at higher engine speeds. Other than a racing engine or one in a pulling tractor, it is not relevant.

For this discussion, a solid lifter is as its name implies: one piece of metal. It can be considered just a means to transfer camshaft lobe action to the pushrod. In contrast, a hydraulic lifter is hollow and has an internal piston and spring, and it allows oil to enter and exit. In many ways, it has similarity to a hydraulic piston on a tractor bucket.

When the valve is closed, the lifter is on the base circle of the cam the round part of the lobe , and the lifter cavity fills with oil. The internal piston is now at its maximum travel upward since the oil is below it. As the camshaft transitions through rotation into opening the valve, the piston is forced down and a check ball usually is employed to close the oil inlet orifice.

Since oil is considered incompressible, the piston can no longer move since the oil is trapped below it and the bottom of the cavity. This now makes the tappet work as a solid lifter and transfers the motion from the camshaft lobe to the pushrod. Over the lift of the camshaft due to valve spring pressure, the oil is pushed out of the lifter cavity by the time the lifter dwells on the nose of the lobe. Once the travel of the lifter on the lobe is complete, the pressure from the pushrod is decreased on the piston and it enters at rest position.

Fresh oil now enters the cavity. If an engine with hydraulic lifters is noisy, then either the internal spring has lost some tension or the check ball is not sealing or allowing the oil to fill the cavity. For all practical purposes, the tappet needs to be replaced. Most hydraulic lifters fail due to poor maintenance. If you want to try to determine which lifter is making noise, pull off the valve cover, start the engine, and let it idle.

Keep in mind that oil will be spraying, so take the proper precautions. This will take up some of the internal piston slap in the lifter and should change the sound. Advertisement Hydraulic lifters are also kinder on valvetrain components than solid lifters because zero valve lash reduces the hammering effect that occurs when the valves slam shut at higher engine speeds. This also reduces noise and helps extend the life of the valvetrain components.

But at high engine speeds say over 6, to 6, RPM , hydraulic lifters experience some limitations. This overextends the plunger and prevents the valve from closing all the way. The same thing can happen if the oil inside the lifter does not bleed down quickly enough between cycles to maintain normal valve lash. This creates too much lash in the valvetrain, which results in noise and loss of power.

Advertisement Hydraulic lifters are precision fit assemblies. The plunger is closely matched to the housing to provide minimal clearance so the leakdown rate is not too great or too small. Do each lifter individually so the original assembly tolerances are maintained.

One of the key differences between stock production hydraulic lifters and aftermarket performance lifters is that the latter usually have tighter internal tolerances for better oil control. Many performance hydraulic lifters also have better valving that allows them to handle more RPMs than their stock counterparts. A good set of aftermarket performance hydraulic lifters will typically allow an engine to rev 1, RPM higher than with stock hydraulic lifters. Some can handle even more RPMs.

Advertisement Hydraulic Adjustments. Hydraulic lifters still need to be adjusted when they are initially installed so the plunger will operate in its mid-range of travel. If the plunger bottoms out, it may prevent the valve from closing causing a rough running engine and possible valve-to-piston contact. A plunger that is over extended and near its upper range of travel may not be able to maintain zero lash as engine temperature changes. This can increase engine noise, and it may even cause the plunger to hammer against the snap ring causing it to fail.

A hydraulic lifter plunger may also become over extended if an engine has sticking valves or excessive wear in the valvetrain. It can only take up so much slack before it runs out of adjustment. Advertisement Something else to keep in mind if you are replacing a set of hydraulic lifters is to make certain the plunger height in the replacement lifters is the same as the old lifters. A difference in plunger height will require longer or shorter pushrods to compensate.

Switching off the fuel injectors to kill certain cylinders saves fuel. But if the valves are still opening and closing the engine is wasting energy pumping air through the dead cylinders. The valves also have to be deactivated at the same time to maximize the energy savings. Advertisement Deactivating the valves traps air in the dead cylinders. The engine squeezes the air during the compression stroke, and the air pushes back as it expands during the downstroke. There are various ways to deactivate cylinders, including cams that have different lobes for each cylinder, changing the position of the rockers or using hydraulic lifters that can collapse on command to eliminate valve lift.

A variable position valve lifter can operate with normal plunger height or reduced plunger height. This requires a secondary oil supply hole and valving to change the position of the plunger inside the lifter. Advertisement The powertrain control module PCM regulates the oil pressure to the lifters via solenoid valves. With multiple cylinder deactivation, several solenoids may be used to control oil flow to various lifter pairs.

Cylinder deactivation adds more complexity to the valvetrain and increases the chance of something going wrong and causing a loss of power if cylinders remain deactivated when they should be producing power. Problems with engine sensors notably MAP, airflow and throttle position sensors , the oil flow control solenoids, engine oil pressure if the engine is also equipped with a variable displacement oil pump , the PCM or wiring faults may all affect the normal operation of such a system.

Advertisement Assembly Tips. When installing a new or reground cam and lifters, use a high pressure cam lube rather than motor oil or general purpose assembly lube to coat the cam lobes and bottoms of the lifters, and use a break-in oil that contains extra ZDDP. The high pressure lube is necessary to protect the cam and lifters following the initial start up and break-in process. A new cam and lifters can be ruined if not broken in properly.

The cam and lifters need plenty of lubrication during this period, and minimal stress as the lifters and lobes get to know each other. Final valvetrain adjustments and engine tuning can be done after the initial cam break-in period is over. Advertisement Roller cams are more forgiving than flat tappet cams as far as break-in is concerned because there is much less friction. Even so, the engine RPMs need to be kept about to RPMs following the initial startup for several minutes to make sure everything is compatible and is getting sufficient lubrication.

Hydraulic lifters will normally make some noise when an engine is initially fired up, but should soon quiet down as oil fill the lifters and the lifters expand to tighten up the slop in the valvetrain.

Some experts say hydraulic lifters should be presoaked in oil and bled prior to installing them. Advertisement The normal procedure for adjusting a set of hydraulic lifters is to rotate the cam so each pair of lifters is at their lowest position on the base circle of the cam. This is done by rotating the crank so that cylinder is at Top Dead Center on its compression stroke with both valves fully closed. The procedure is then repeated for each cylinder until all the lifters have been preset.