The two main types of lifters are solid lifters and roller lifters.
1. Solid lifters: These lifters are made of solid metal cylinders. They are simple in design and function. As the camshaft rotates, it either presses down on the lifter or allows it to rise. Solid lifters have been used in engines for many years and are known for their durability and reliability. They work well at lower RPMs and are commonly found in older or less performance-oriented engines.
However, solid lifters do have some limitations. One major drawback is the need for periodic valve lash adjustments. Valve lash refers to the small gap between the valve stem and the rocker arm or pushrod. Over time, this gap can change due to wear and thermal expansion. If the valve lash becomes too large or too small, it can result in poor engine performance or damage to the valvetrain. Regular maintenance and adjustment are required to ensure proper valve lash.
2. Roller lifters: Roller lifters are a more advanced type of lifter. They have a roller wheel or roller bearing at the bottom, which rolls along the camshaft lobes instead of sliding. This reduces friction and wear, allowing for smoother operation and improved performance. Roller lifters are commonly used in high-performance and racing engines.
One key advantage of roller lifters is their ability to handle higher RPMs without excessive wear. The roller design reduces friction, heat, and wear on the camshaft lobes, resulting in improved longevity and performance. Roller lifters also require less frequent valve lash adjustments compared to solid lifters.
Additionally, roller lifters can be equipped with hydraulic mechanisms. Hydraulic roller lifters use oil pressure to automatically adjust the valve lash, eliminating the need for manual adjustments. This makes them more convenient and maintenance-friendly.
Solid lifters are simple and durable but require regular valve lash adjustments. Roller lifters, on the other hand, offer smoother operation, improved performance, and reduced maintenance requirements. They are particularly beneficial for high-performance applications where reliable operation at higher RPMs is crucial.