What does cam duration effect?
At high rpm, longer intake duration fills the cylinder. This results in lower cylinder pressure and less low-end power. Long duration camshafts also create more Valve Overlap. At high rpm, this helps promote the Scavenging Effect. But at low rpm, it also contributes to Exhaust Reversion.
How is the timing of the cams set?
Cam timing is what determines when the valves open and close with respect to the position of the pistons in their bores. It is set when the engine is built- by placing the camshaft and crankshaft in the correct relationship. It cannot be adjusted on a stock engine.
How does cam timing and Cam separation affect the engine?
The following tables illustrate how variations in lobe separation angle and cam timing will effect the behavior of the engine in which the camshaft is installed.
How are camshafts measured in Summit Racing Cars?
Summit Racing’s got a handy camshaft timing calculator that can help you determine the right cam specs for your performance needs. This simple upward movement of the cam lobe can be measured in terms of inches (or millimeters) of lobe lift.
Do you need degree wheel for Camshaft Timing?
Before you start any of this you will need to have a degree wheel to time your motor: Finding piston TDC Timingyour camshaft involves measuring total lobe lift, the lobe centerlines for both the intake and exhaust lobes, camshaft duration at 0.050-inch lift, and lobe separation.
What are the specifications on a camshaft timing card?
One area of confusion is certainly a camshaft timing card. All aftermarket and production camshafts use a series of terms and specifications to identify their operating characteristics.
What are the specs for a camshaft valve?
CAMSHAFT SPECIFICATIONS (Cont. ) Part No. Specs @ 0.50 Cam Lift Opens Closes Duration SAE Specs@ (0.06/Rocker Arm Ratio) Cam Lift Opens Closes Duration Cam Lift Gross Valve Lift Center Line C/L Rocker Arm Ratio Valve Lash Clearance
The following tables illustrate how variations in lobe separation angle and cam timing will effect the behavior of the engine in which the camshaft is installed.
How does the summit racing cam timing calculator work?
To learn how to use the calculator and find a cam based on results, watch How the Summit Racing Cam timing Calculator Works. For a step-by-step guide to choosing individual events, watch How a 4-Stroke Engine’s Piston Motion and Valve Events Interact.