How do you calculate cam duration?

How do you calculate cam duration?

How is it measured?

1. Using a Dial Indicator and Degree Wheel, find the opening and closing points of the valves at 0.050 in. of lift. If the intake valve opens AFTER TDC, use a negative value. If the exhaust valve closes BEFORE TDC, use a negative value.
2. Add the numbers together.
3. Add 180° to find duration.

How is cam advance calculated?

Compare the centerline to the value listed on the Cam Card.

1. If different than the listed value, the cam is either advanced or retarded.
2. For example, if the intake centerline is listed as 107° and you find it at 103°, the cam is advanced 4°.

How do you calculate valve timing events?

To calculate the duration of any intake valve timing event, add 180° to the intake opening and closing time. For example, if an intake valve opens at 12° before top dead center (BTDC) and closes at 40° after bottom dead center (ABDC), the duration of the valve timing event is 232°.

How do you calculate the RPM of a cam?

There is no formula to find the rpm range for a camshaft. If you have questions, the best course of action is to contact the manufacturer….How is it measured?

1. Carburetor CFM Rating,
2. Intake Runner Volume,
3. Combustion Chamber Volume,
4. Valve diameter,
5. Header Primary Size,
6. Compression Ratio,
7. Engine Displacement,
8. Etc.

What is a good camshaft duration?

A 280-degree-duration cam holds the valves open longer than a 260-degree-duration cam. Holding the valves open longer allows more air and fuel into the engine and also allows more to get out through the exhaust. Longer duration (higher number) improves top-end power but almost always sacrifices low-end torque.

How does duration affect a camshaft?

Duration has a marked effect on a cam’s power band and driveability. Higher durations increase the top-end at the expense of the low-end. Measuring duration at 0.050-inch tappet lift has become standard with most high-performance cams.

How is cam lift calculated?

Simply measuring the diameter of the base circle, and subtracting that from the largest diameter of the cam, the lobe lift, will calculate the lift of the cam.