Thursday, December 1, 2022
Terminology of Camshaft
Car Tech

Terminology of Camshaft


Some might say that the camshaft is the engine’s brain or heart. It controls when the valves open and close, how long they stay open, and how far they move. For every two turns of the crankshaft, one turn of the camshaft happens. 

On most engines with valves in the top, there are two main types of camshafts: flat tappet and roller. Whether you are building an engine for the first time or want to improve its performance using cylinder liner manufacturers, you need to know how camshafts are made and their specs. Many numbers and words describe how the camshaft is made, and it is essential to know how these numbers affect how your engine works.


1. Base Circle

The valve lash adjustments are made in the base circle, which is the round part of the cam lobe. Base circle runout is a slight rise on the base circle.

2. Cam Lift

This is how far the cam lobe can move the lifter. Because the rocker arm ratio makes the overall valve lift bigger, this is not the same as the valve lift.

3. Lobe Separation 

The Lobe separation angle is between the intake and exhaust lobes’ maximum lift points, or centerlines, in camshaft degrees. It is usually based on what the engine is used for, how big it is, and how tight it is. A lobe separation angle of 112 degrees means that the points where the intake and exhaust lobes open the most are 112 degrees apart. This is another way to talk about valve overlap: how long both valves on the same cylinder are open simultaneously.

4. Cam Profile

The cam profile shows the shape of the camshaft lobe. The nose of the lobe on a flat tappet camshaft is a bit more pointed, while the nose of the lobe on a roller lift camshaft is more round.

5. Degreeing the Camshaft

This is how the camshaft and crankshaft are made to work together. 

Camshaft manufacturing companies in India use a degree wheel to set this measurement for the best engine performance. On the cam card, most manufacturers will list the exact specs for each cam.

6. Break In

When installing this roller cam, it is essential to lubricate it, but when installing a solid flat tappet cam, it is essential to follow the break-in steps carefully. The most crucial part of the cam break-in is the first 10 minutes. Failure is likely to happen if the proper instructions and installation steps are not followed, and the right parts are not used.

7. Valve Clearance 

Valve clearance also called a lash adjustment, ensures that the valves close on their seats, no matter how hot or cold the engine is. Because most modern engines are made of different metals, their expansion rates vary when they reach operating temperature. Different rates of expansion are automatically taken into account by hydraulic tappet systems. Still, engines with solid flat tappets or solid roller tappet systems need to have the lash adjusted from time to time. As the engine warms up, there is usually more space between the rocker tip and the valve tip.

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