Lifters in a Car Engine
What are Lifters?
Lifters, also known as valve lifters or tappets, are mechanical components found in the valvetrain of an internal combustion engine. They play a critical role in opening and closing the engine’s valves, which control the flow of air and fuel into and out of the cylinders.
Types of Lifters
There are several types of lifters used in car engines, each with its own unique design and characteristics:
Flat Tappets
Flat tappets are the simplest type of lifter, consisting of a cylindrical body with a flat, hardened surface on one end. They slide directly on the camshaft lobes, which rotate to open and close the valves.
Roller Lifters
Roller lifters use a small roller bearing between the lifter body and the camshaft lobe. This reduces friction and wear, allowing for higher engine speeds and improved valve timing.
Hydraulic Lifters
Hydraulic lifters are filled with oil and have a built-in piston that compensates for any clearance between the lifter and the camshaft lobes. This helps maintain proper valve timing and reduces valve noise.
Lash Adjusters
Lash adjusters are similar to hydraulic lifters but have an adjustable screw that allows for precise adjustment of the valve clearance. This is necessary on engines with overhead camshafts (OHC) or overhead valves (OHV).
Function of Lifters
The primary function of lifters is to convert the rotary motion of the camshaft into reciprocating motion to open and close the engine’s valves. As the camshaft rotates, its lobes push on the lifters, which then transfer the force to the pushrods (in engines with pushrod valvetrains) or directly to the valves (in engines with overhead camshafts).
The lifters also play a role in adjusting the valve clearance, which is the gap between the valve and its seat. Proper valve clearance is essential for ensuring that the valves open and close at the correct time and duration.
Lifter Failure
Lifters can fail for various reasons, including:
- Excessive wear
- Contaminated oil
- Improper valve clearance
- Defective components
Lifter failure can lead to a variety of engine problems, including:
- Loss of power
- Poor fuel economy
- Excessive valve noise
- Engine overheating
Lifter Maintenance
To ensure proper lifter function and longevity, it is important to perform regular maintenance:
- Use high-quality engine oil and replace it at the recommended intervals.
- Inspect the lifters for wear or damage during routine engine maintenance.
- Adjust the valve clearance according to the engine manufacturer’s specifications.
- Replace worn or damaged lifters as necessary.
Conclusion
Lifters are essential components of a car engine, playing a crucial role in controlling the flow of air and fuel into and out of the cylinders. By understanding their function, types, and maintenance requirements, you can ensure that your engine operates efficiently and reliably for years to come.
