How do you measure camshaft specs?

Measure the base circle diameter and subtract that number from the overall lobe height. You might be able to find a cam with matching lift numbers.

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 cam overlap?

There are a couple different ways to calculate the overlap of the cam. 1) The easiest way is to add the intake opening times to the exhaust closing time. Seat to seat times (advertised duration) must be used. . 050″ durations or timings will not give the correct overlap.

What is a camshaft design?

The cam lobes, one for each valve, contain all the variables. The cam lobes control not only total lift and when the valves open and close, but also valve speed, acceleration, overlap, and even how much cylinder pressure is developed at speed. There are a few parts of the lobe design critical to achieving this.

What is the base circle of a camshaft?

BASE CIRCLE: The “base circle”, also known as the “heel”, is the lowest point of the camshaft lobe and is the place where the valve is in the closed position. The “base circle” is the point where all valve lash settings are made.

How is cam Duration calculated?

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.

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 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.

What is cam rpm range?

Definition & Description. The basic operating rpm range for a camshaft is its “sweet spot.” This range is where the engine will produce the most Torque and Horsepower.

What is lobe lift?

Lobe Lift is the amount (usually in inches) that the cam lobe increases in radius above the cam base circle. Tip: To quickly find maximum lobe lift, measure the base circle of the cam and subtract it from the thickness across the cam lobe’s highest point (see the diagram below).

How are cams specified?

The cam’s centerline specification is used to determine the position of the lobes on both the cam and as installed in the engine. Most cam companies include an intake centerline number, which is the position of the intake lobe centerline (in crankshaft degrees) relative to top dead center on piston number one.

How to determine cam duration?

Cam manufacturers agreed on a standard to measure duration so all cams are measured the same way. The idea is to measure duration starting at .050 inches of tappet (lifter) movement. As the lobe lifts the tappet up, when the tappet moves .050 inches, the duration is measured from that point.

What is high performance camshaft?

A performance camshaft… usually a higher lift on the lobe, which increases in length of the valve stroke, which allows for more air to enter through the inlet valves, increasing the power potential of the engine. altered valve timing – essentially modify when the valves open and close, which has an impact on the effective compression ratio,…

What is cam timing?

Cam timing is a relationship between where the cam is indexed at (phased) with the crank. When it is referred-to as “straight-up” or at “zero”, it means it is degree for degree in line with the TDC index of the crank, where the cam manufacturer wanted the cam to be at.

What is camshaft duration?

Camshaft duration is the period of time, measured in degrees of crankshaft rotation, that a valve is open. “Advertised duration” measures duration from the point where the cam manufacturer believes the lobe starts raising the lifter.