How should I advance retard a cam?
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….How does it affect performance?
| Advance | Retard | |
|---|---|---|
| Intake Valve Opening Event | Happens sooner | Happens later |
What happens when you advance camshaft timing 4 degrees?
Advancing a camshaft from its original position causes all of these valve events to happen earlier in the cycle. A camshaft advance of 4 degrees will cause each opening and closing event to occur four degrees sooner than before, changing the ability of the cylinder to build pressure.
How does advancing or retarding a camshaft work?
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.
What’s the difference between Cam 4 and 6 degrees?
Others will of course differ. The cam can be advanced or retarded from the card specs up to 6 degrees. Advancing the cam will move the power band down in the RPM range. (Increased low-rpm torque). Whatever you gain on the bottom end you will lose on the top. Retarding the cam will move the power band up in the RPM range.
How does an advanced CaM affect the engine?
Although all valve events occur earlier, the greatest impact of an advanced cam is to close the intake valve sooner in the compression stroke. This means that a greater volume of air and fuel gets trapped and compressed before being ignited and has the effect of creating more torque and power.
Advancing a camshaft from its original position causes all of these valve events to happen earlier in the cycle. A camshaft advance of 4 degrees will cause each opening and closing event to occur four degrees sooner than before, changing the ability of the cylinder to build pressure.
How does advancing the CaM affect the RPM?
Advancing the cam will move the power band down in the RPM range. (Increased low-rpm torque). Whatever you gain on the bottom end you will lose on the top. Retarding the cam will move the power band up in the RPM range. If 6 degrees is not enough, a different camshaft profile would be needed.
Others will of course differ. The cam can be advanced or retarded from the card specs up to 6 degrees. Advancing the cam will move the power band down in the RPM range. (Increased low-rpm torque). Whatever you gain on the bottom end you will lose on the top. Retarding the cam will move the power band up in the RPM range.
What happens when you increase the timing advance?
Increasing the timing advance raises the high-end power, reducing the low-end. Decreasing the timing advance raises low-end power, reducing the high-end. Example: Magneto timing was reduced 6 degrees in our blown alcohol drag racer, and our low-end 60-foot times were quicker by 0.05 seconds from more low-end power.