NewCams | Camshaft | Cast / Steel / Assembled Camshaft

A Basic Overview of Cam Timing

To advance or retard a camshaft is to change the alignment between the camshaft and the crankshaft.

When a cam is installed "straight-up," the imaginary centerlines of the two shafts line up exactly. Advancing or retarding the cam pushes the centerline of the camshaft to one side or the other of the crankshaft centerline. This changes the Timing of the valve opening and closing events, in relation to the position of the piston in the cylinder.

How is it measured?

Find the lobe centerline in relation to the piston's position in the cylinder.
a. This is known as "degreeing the camshaft."

b. This should be done when building an engine or replacing a camshaft.

c. Follow this link for the process to Degree the Camshaft.
Compare the centerline to the value listed on the Cam Card.
a. If different than the listed value, the cam is either advanced or retarded.

b. For example, if the intake centerline is listed as 107° and you find it at 103°, the cam is advanced 4°.

Some camshafts are designed with "ground-in" advance. Follow this link to learn more about Ground-In Advance

How does it affect performance?

Advancing or retarding the cam will move the Torque curve higher or lower in the rpm range.

	Advance	Retard
General Effect	Improves low-end power and throttle response	Improves power at higher rpm's
Intake Valve Opening Event	Happens sooner	Happens later
Piston to Valve Clearance	Decreases intake valve clearance	Increases intake valve clearance
Moving 4° Causes...	Peak torque about 200 rpm sooner	Peak torque about 200 rpm later