Full Answer
What is camshaft lift and duration?
The easiest way to explain camshaft lift is to think of it as how far the valve opens to its furthest point off of the valve seat. Camshaft duration can be simply explained as how long the valve stays open off of the valve seat.
How do you measure the duration of a camshaft?
How is it measured? Most Cam Cards will list duration. However, if you want to find the duration for the camshaft in your engine, you can calculate it. Using a Dial Indicator and Degree Wheel, find the opening and closing points of the valves at 0.050 in. of lift.
What are the specs of a 380 Exhale Cam?
Thank you. The cam specs are 380 exh lift, 360 int lift and 244 exh and 266 int duration. Very small camshaft, but reliable. Crane made them in a blueprint series 2-3 years ago, but stopped making them.
What is the duration of a big cam?
Duration is how long the valve is off its seat. It is listed in degrees of crankshaft rotation. When someone refers to a "big cam," they mean it has longer duration, not higher Lift. Manufacturers often list 2 different duration values:
Why is a camshaft higher at high RPM?
This creates more power. (It is why a camshaft's RPM Range is based on its duration.) However, at low rpm, the open valves reduce the pumping pressure of the piston.
What does "big cam" mean?
When someone refers to a "big cam," they mean it has longer duration, not higher Lift. Manufacturers often list 2 different duration values: Advertised Duration is the degrees of crankshaft rotation that the lifter is raised more than a predetermined amount. This predetermined amount varies between manufacturers.