What do the numbers mean on camshafts?

What do the numbers mean on camshafts?

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.

What does LSA mean in camshafts?

Lobe-Separation Angle
What Is Lobe-Separation Angle? LSA is the distance from the centerline of the intake lobe to the centerline of exhaust lobe. It is the average centerline between both lobes and expressed in degrees ranging from 95 on the extremely narrow/tight side to upward of 120 on the wide end.

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 .

What does +2 mean on cam LSA?

The + 2 or + 4 designation after the LSA is the amount of advance ground into the cam if it was installed straight up. This will effect the intake centerline like you stated. Neal.

How do you read a camshaft specs?

Reading a Cam Card: Lobe Separation Angle (LSA) This figure is derived by adding the intake center line plus the exhaust center line and dividing by two. In this case: 108 + 116 = 224 degrees / 2 = 112 degrees.

What does an oversized cam do?

A bigger cam will open the intake valve wider, allowing more fuel and air into the cylinder. The larger the cam, the more fuel that is let in.

Why do cammed engines lope?

Again, keeping all else constant, more duration will make the engine less efficient at low rpm, with more overlap dilution of the induction charge, and the later intake valve closing reducing the trapping efficiency. Therefore, a long-duration cam will cause rough running at idle (lope) and a loss of low-rpm torque.