How Is Camshaft Length Calculated?

This is usually calculated by

dividing the sum of the intake centerline and the exhaust centerline by two

. This measurement is another way of expressing valve overlap, the amount of time that both valves are open on the same cylinder; as well valve opening and closing points and lobe centerline.

How is camshaft centerline calculated?

Finding the centerline is easy.

Rotate the engine clockwise until you find the maximum lobe lift, then zero the indicator

. Now rotate backward about 0.100 to 0.150-inch to compensate for timing chain slack. Then rotate clockwise until you reach 0.050 inch.

How do camshaft sizes work?

Typically camshaft manufacturers list this measurement by

multiplying the cam lobe lift by the stock rocker arm ratio

, usually 1.5:1. For example, if your cam lobe lift is . 319 and you’re using a 1.5:1 rocker arm ratio, you can take . 319 x 1.5, which is .

How is a camshaft profile measured?

Typically camshaft manufacturers list this measurement by

multiplying the cam lobe lift by the stock rocker arm ratio

, usually 1.5:1. For example, if your cam lobe lift is . 319 and you’re using a 1.5:1 rocker arm ratio, you can take . 319 x 1.5, which is .

What does duration mean on a camshaft?

DURATION: Duration is

how long the cam holds the valves open

. It’s expressed in degrees of crankshaft rotation (remember, the cam rotates at half the speed of the crank). A 280-degree-duration cam holds the valves open longer than a 260-degree-duration cam.

What is a good camshaft duration?

Performance cams typically have durations ranging from

220 up to 280 degrees or more

. The longer the duration, the rougher the idle and the higher the cam’s power range on the rpm scale. A cam with a duration of 240 degrees of higher will typically produce the most power from 3,500 to 7,000 rpm.

What do camshaft numbers mean?

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. … Advertised Duration is the degrees of crankshaft rotation that the lifter is raised more than a predetermined amount.

How do I know if my camshaft is worn out?

1. Active check engine light.
2. Loud ticking or tapping sounds.
3. Metal debris in the engine oil.
4. Cylinder misfire.
5. Increased emissions as a result of misfiring.
6. Visible signs of damage.

How do you read a camshaft?

The are two

measurements, duration and valve lift

. The duration of measured in degrees ex 278, 288 like you gave. This measures how long the valve will stay open. For example, 278 degrees of rotation of the roller the valve will be closed. The other 82 degrees of rotation is where the valve will be open.

How do you call a camshaft?

Locate the ID number on the camshaft. It is typically

located in the center of the cam between the lobes

. The ID number will consist of either eight or nine digits; the last four numbers identify the cam and its specific application.

Does a cam increase horsepower?

Performance cams increase the duration and timing of the valve openings during the engine stroke,

increasing horsepower

and making your car accelerate more quickly. You’ll idle slightly rougher with a performance cam, but get a throaty rumble that’s desirable for some gearheads, depending on your vehicle.

What is considered a mild cam?

In general, a stock replacement camshaft with duration of less than 200 degrees will have a lobe separation angle of more than 114 degrees. An

RV or towing camshaft

, which is considered a mild performance or an economy cam, will often have a narrower LSA, between 112 and 114 degrees.

What determines cam rpm range?

The rpm range is determined by

the camshaft manufacturer

. The listed range is a result of testing the camshaft on a dyno with different combinations of engine parts. … Engine Displacement, Etc.

How do I know what camshaft to buy?

The

rpm

range is the range where the engine performs best. When selecting a camshaft, choose one with an rpm range that matches the other components of your vehicle and its intended use. Follow this link for more about Basic Operating RPM Range.

Can a camshaft increase compression?

Overlap causes a “scavenging effect” as the engine RPM increases. This is why performance cams “come alive” at higher RPMs. It’s not “just” the cam making the power, it’s the cam’s scavenging effect working as the RPM increases which

increases

cylinder pressure (dynamic or effective compression).