What damage can a bad lifter do

Lifter tappets aren't quite as simple as they seem at first glance. The hydraulic lifter is a sort of self-contained hydraulic system, utilizing a number of tiny components in order to control valve train movement. While replacing a collapsed lifter is simple -- at least compared to fixing the engine if you don't replace it -- don't rush into the job until you know what you're dealing with.

Lifter Basics

Lifters are the small cylinders that sit in between a camshaft's lobes and the pushrods. With a hydraulic lifter, the bottom of the pushrod sits on top of a plunger, which in turn sits on top of a cylinder full of oil. Oil pressure pushes up on this plunger, stacking up slack, or "lash," in the system. In addition to taking up valve lash, most lifters stay slightly collapsed at low engine rpm, slightly reducing the distance that the valve opens to enhance bottom-end torque and while encouraging a smoother idle.

Symptoms

When the plunger inside of a lifter fails, it'll fail to maintain oil pressure and will remain in a collapsed state at all times. When that happens, the lifter will fail to take up lash in the system, which causes parts inside to hammer against each other during initial contact. This hammering manifests as a very noticeable tapping that increases in volume and frequency with engine rpm. A bad lifter will throw off the affected cylinder's ability to move and burn air and fuel, which will typically lead to spark plug fouling and a consistent miss on that cylinder.

Consequences

A collapsed lifter puts a great deal of stress on a vehicle's valve train, and the weakest link is usually the pushrod. Collapsed lifters can easily bend pushrods, which will subsequently fall out of the space between the rocker arm and the top of the lifter. Once a push rod falls out of the space, the very least you can expect is a dead cylinder. Worst-case scenarios include broken rocker arms, broken valves, cracked heads, a damaged cam or complete engine destruction depending upon what breaks, how it breaks and when.

Replacing Flat Tappets

Replacing a collapsed lifter isn't quite as simple as you might think. While the shade-tree mechanic might simply pop the intake off and replace the faulty lifter, Ol' Scruffy isn't looking at the big picture. Cams and flat-tappet lifters are a matched set; they're broken in together at the factory to establish matching wear patterns. Putting a new lifter on an old cam is like trying to sharpen a set of ice skates with a waffle iron, and it's only a matter of time before that new lifter takes out your cam. But dropping in a replacement lifter is better than allowing lash to destroy your engine, so consider it as a band-aid fix.

Replacing Roller Tappets

Roller-tappet lifters and cams are the exception here, since far less wear occurs when using a roller tappet. Generally, you can get away with replacing a single collapsed roller lifter without replacing the cam. This isn't true in all cases, but again, better to replace the lifter and risk a cam replacement later than to allow a $15 part to destroy your entire engine.

References

• "How to Rebuild Small-Block Chevy LT1/LT4 Engines"; Mike Mavrigan; 2002
• "How to Build and Modify GM LS-Series Engines"; Joseph Potak; 2009

Writer Bio

Richard Rowe has been writing professionally since 2007, specializing in automotive topics. He has worked as a tractor-trailer driver and mechanic, a rigger at a fire engine factory and as a race-car driver and builder. Rowe studied engineering, philosophy and American literature at Central Florida Community College.

More Articles

A lifter is connected to the crankshaft of your car, thus driving beyond 100 miles with a bad lifter can result in heavy damages that can be expensive for you to repair. If you’re driving a car with bad lifters, you might experience engine shudder or misfire during acceleration.

How Long Can You Drive With Bad Lifters? You can drive your vehicle max to 80 -100 miles with the bad lifters. However, please do not ignore the problem of bad lifters, and do not drive with it for more than 100 miles to prevent further car damages. 

Bad lifters can also cause the engine to backfire when it’s idling. If you notice any of these symptoms, it’s a good idea to have your car checked out as soon as possible because bad lifters can cause other problems to occur in the future if left unchecked. 

Table of Contents

• What Are Lifters On A Car?
• How Hydraulic Lifters Work? 
• 5 Symptoms Of A Bad Hydraulic Lifter.
• Engine Lifter Replacement Cost .

What Are Lifters On A Car?

Lifters are often located in the upper cylinder heads and linked to the camshaft with a push rod so engine oil can move the lifter up or down. It is this movement that controls valves opening and closing during piston travel.

The average car weighs about 3,000 pounds or 1.5 tons. While that isn’t a lot compared to some of the larger and heavier vehicles on the market, it’s still a significant amount of weight. 

A motorist can use their vehicle for several years without adding any additional weight elsewhere in their car, but what happens before? That’s where lifters come into play. 

These units are typically installed to your trunk, back trunk lid, and rear bumper to help with the strain put on these areas during regular driving operations.

 Lifters are designed for several purposes and can prevent damage either now or in the future. Since a lifter is directly linked to an eccentric shaft in the camshaft, it works directly with engine timing, which means that a clogged lifter will not work at all. 

However, if you can hear some knocking sounds coming from your engine when driving your car, you are probably dealing with a clogged or dirty lifter. Thus you should check for the dirty lifters and should clean them from time to time for proper functioning.

How Hydraulic Lifters Work? 

A hydraulic lifting mechanism is a device that lifts objects using pressurized fluid under a pressure difference. This is done by using an eccentric rotating motion that causes a piston to slide back and forth in a cylinder with the help of an attached rod and belt. 

The rod can pull on the belt, which generates force at one end of the cylinder and pushes against an object or another component at the other end, thereby lifting it.

Hydraulic lifters use a liquid to create a cushion of air that can take up any lost space in your engine. For example, if your piston rod moves up and down while the cylinder walls stay still, it leaves a small amount of space at either end of the rod. 

If the engine has a too low ratio for that amount of movement, the piston can hit this space and damage your engine. 

The hydraulic lifters lift the rod high enough to completely move up and down, sometimes with more than 100% of its original weight. This high movement, combined with additional weight brought by the liquid, makes all moving parts run much smoother.

Hydraulic lifters are not the same as some high-end engines’ solid or mechanical lifters. These lifters are used in most cars, especially older models. 

They can be used with various engines and compression ratios to reduce engine noise. Sometimes they use a stiffening spring to keep the lifter still after it is pressed. 

Clunking Noise When Braking : 5 Causes And Solutions

EngineDiary

5 Symptoms Of A Bad Hydraulic Lifter.

Hydraulic lifters are a common component of modern cars. The lifters are often created with a steel cylinder, around which an oil reservoir is housed. When the fluid in the reservoir is pressurized, it forces the piston down, allowing smooth and efficient movement. 

Nowadays, hydraulic lifters may be found on vehicles from almost all manufacturers. The good news is that, in most cases, a hydraulic lifter will fail gradually.

 In some cases, it may fail suddenly, causing immediate difficulty in starting the car. A bad hydraulic lifter will have several symptoms. 

The five most common ones are:

• Sticky Lifters 
• Dead Cylinders    
• Valve Issues 
• Leaky Pipes 
• Incomplete Shutdowns

It is important to note that a bad hydraulic lifter can indicate a larger issue. For example, if your vehicle is experiencing misfires and valve leaks, the problem might be linked to a dirty fuel injector or faulty oxygen sensor. 

If you experience any of these with your car, you should take it in for repair. A skilled technician should be able to identify these issues and repair them so that you can be back on the road. 

It’s also important to note that a bad lifter can cause problems with your valve train. A dirty lifter could cause a valve to get stuck in the open or closed position.

 A leaking lifter could allow oil to make its way into your cylinder and contaminate your sparkplugs, causing misfires. If you’re experiencing odd behavior with your engine or if it’s simply not performing the way it used to, then you should take it in for a proper diagnosis.

Engine Lifter Replacement Cost .

If you notice your engine is not working as it should, it might be time to replace the engine lifters for your car. Engine lifts are relatively expensive and can cost up to 1000$ to 3000$ depending on the type of vehicle you have. 

The decision to repair or replace a defective component in a car is often an important one, which is why determining whether or not this repair is necessary takes consideration of three factors: parts costs, labor costs, and defect severity.  

Thus replacing engine lifters is a costly process and will depend upon many factors. But if you want to save some money, you can try to replace it if you know all the steps of fixing it. But it is advised to take your car to an excellent mechanic to change the lifters and avoid any other problems with your vehicle.