A camshaft is an impressive hunk of metal that does some amazing things inside an engine. The camshaft acts as the quarterback of the valvetrain, barking out orders as it rotates to ensure the valves are opening and closing on time. Camshaft timing and lobe separation angle (LSA) are two of the big factors that determine how a cam will behave, and how an engine will make power.
Cam timing is what governs the opening and closing of valves along with valve overlap. These are important actions during the combustion process since they dictate how and when an engine makes power. Piston-to-valve clearance is also affected by the timing of a camshaft, so it’s something you need to get right to avoid catastrophic engine failure. So, when you change cam timing it will affect when the intake and exhaust valves open.
LSA is a measurement of the distance from the centerline of a camshaft intake lobe to the centerline of the exhaust lobe and is expressed in degrees. The lower the LSA number, the narrower or tighter it is, and the larger the number, the wider it is. When you start to make changes to the LSA of a camshaft, you will move where it makes torque, how much torque it makes, how the engine idles, and much more. LSA really becomes a factor if your engine has a power adder.
Now, there’s a lot more that goes into the science of cam timing and LSA. COMP Cams has created a great table that explains what happens when you start to make changes to camshaft timing and LSA. Click right here to see the table so you can learn more about what happens when you change camshaft timing and LSA.