How is camshaft lobe separation calculated?

Cam Lobe Separation Lobe separation can be measured using a dial indicator and a degree wheel, but is usually calculated by dividing the sum of the intake centerline and the exhaust centerline by two.

How are cam timings measured?

To find exact TDC, first set the dial indicator to zero at the point of highest piston travel. Next, turn the crankshaft counterclockwise about 90 degrees. Then, slowly rotate the crankshaft clockwise (the normal direction of engine rotation) until the indicator is . 030″ below the TDC (zero) setting.

How is cam lobe centerline calculated?

To find the intake lobe centerline, divide the intake duration by two and subtract the indicated intake opening point as shown in our example with the Comp XE274 example. Sometimes you find a very mild or stock cam where the IO occurs after TDC (ATDC). In this case just add the IO figure to one half of the duration.

What determines valve timing?

Camshaft. In four-stroke cycle engines and some two-stroke cycle engines, the valve timing is controlled by the camshaft. It is also affected by the adjustment of the valve mechanism, and particularly by the tappet clearance.

How is cam lobe lift calculated?

Simply measuring the diameter of the base circle, and subtracting that from the largest diameter of the cam, the lobe lift, will calculate the lift of the cam.

How do I check my cam timing?

To confirm accuracy, you need a dial indicator with a measuring range of at least 1 inch on each lifter. With both valves closed, set the dial indicator at zero. Begin with the intake valve; slowly turn the crank clockwise until the lifter rises 0.050 inch. Stop turning the crank and read the degree wheel.

How is cam lift calculated?

How is cam degree calculated?

D.C. To determine the amount the camshaft is advanced in crankshaft degrees, simply subtract the difference between the intake and exhaust Top Timing and divide by two. In this case 37° – 29° = 8° ÷ 2 = 4 crankshaft degrees of advance.

How is intake valve duration calculated?

How is it measured?

1. Using a Dial Indicator and Degree Wheel, find the opening and closing points of the valves at 0.050 in. of lift. If the intake valve opens AFTER TDC, use a negative value. If the exhaust valve closes BEFORE TDC, use a negative value.
2. Add the numbers together.
3. Add 180° to find duration.