2006-12-17 11:18:38 · 5 answers · asked by mono 1 in Cars & Transportation ➔ Maintenance & Repairs
It depends if the cam is in the engine, or out of the engine. You measure it with a dial indicator. Lift is how far off the base circle the lobe goes, and duration is the amout of degrees the lift takes place from base circle through the lift, and back to the base circle. If you do this in the engine, you must use a degree wheel and a dial indicator to find the base of the circle. Zero your indicator, and turn the engine by hand in the direction the engine runs. When the indicator begins to rise, back the engine up, and find the exact point the indicator begins to rise. This will be your zero or starting point. Set the degree wheel at zero to align with the marker on the timing cover or engine. If you have no pointer, then make one out of a piece of wire. Turn the engine in the direction it runs until the indicator stops raising on the lobe, this will be your number in thousands that the lift of this lobe is. Now continue to turn the engine until the indicator reaches zero again (in the direction the engine runs), and how many degrees that is on your wheel at the pointer will be your duration of lift.
If you need more information on measuring a cam, you can get the full information at www.cranecams.com and go to the technical section, and there is some good pictures as well as all the information to spec out a cam fully. What I have put here is just a basic idea of how to do it. It is complex, and if you don't understand machinest terms and tools, then you will be at a loss.
Glad I could help. Good Luck!!!
2006-12-17 11:51:58 · answer #1 · answered by Anonymous · 1⤊ 0⤋
Measure the height of the lobe and subtract the width . thats the size of the cam. You need to find out what the rocker arm ratio is to get the valve lift. If you cam has a .320 lift and your rocker ratio is 1.5 your valve lift is .480 , if its a 1.6 ratio the valve lift is .512 .
2006-12-17 11:23:38 · answer #2 · answered by Thomas H 4 · 0⤊ 1⤋
LIFT AND DURATION. LIFT IS HOW HIGH THE CAM SHAFT LIFTS THE VALVE, DURATION IS HOW LONG THE VALVE IS OPENED FOR. YOU MIGHT HAVE TO USE A DIAL INDICATOR.MANY CAM SHAFTS ARE MARKED ON THE END (FROM THE MANUFACTURER).
2006-12-17 11:26:57 · answer #3 · answered by crane1951@sbcglobal.net 4 · 0⤊ 1⤋
Depends, duration or lift?
2006-12-17 11:20:55 · answer #4 · answered by Mr. KnowItAll 7 · 0⤊ 1⤋
Very carefully.
2006-12-17 11:21:39 · answer #5 · answered by Bill 1 · 0⤊ 1⤋