Question about lifter operation
03-01-2010, 10:16 PM
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Question about lifter operation So, the engineer and I, aka jeffe, were having a discussion about hydraulic roller lifters.
If I am thinking correctly, there is a spring inside the lifter beneath the pushrod cup. There are also oil passages, maybe of varying size for pressurization purposes? When oil pressure is up, the lifter experiences a positive pressure, increasing the net resistance of the pushrod moving into the lifter. Is this so far correct?
If so, when the engine shuts off, the supply of positive pressure has ceased, therefor it is just a matter of a few moments before equilibrium is restored inside the lifter and the only force acting on the pushrod cup is that of the spring force. Good?
If you were to push down on the lifter, you would still have some resistance against it, more than that of just the spring because oil is still inside the lifter, and it has to escape through the small oil passages, but once that is removed, only force available is that of the spring force. Good?
Is what I have thus far, good? I have more, but at the current time cannot remember, and this is a long enough OP for a non sticky technical post.
If I am thinking correctly, there is a spring inside the lifter beneath the pushrod cup. There are also oil passages, maybe of varying size for pressurization purposes? When oil pressure is up, the lifter experiences a positive pressure, increasing the net resistance of the pushrod moving into the lifter. Is this so far correct?
If so, when the engine shuts off, the supply of positive pressure has ceased, therefor it is just a matter of a few moments before equilibrium is restored inside the lifter and the only force acting on the pushrod cup is that of the spring force. Good?
If you were to push down on the lifter, you would still have some resistance against it, more than that of just the spring because oil is still inside the lifter, and it has to escape through the small oil passages, but once that is removed, only force available is that of the spring force. Good?
Is what I have thus far, good? I have more, but at the current time cannot remember, and this is a long enough OP for a non sticky technical post.
03-01-2010, 11:31 PM
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So, the engineer and I, aka jeffe, were having a discussion about hydraulic roller lifters.
If I am thinking correctly, there is a spring inside the lifter beneath the pushrod cup. There are also oil passages, maybe of varying size for pressurization purposes? When oil pressure is up, the lifter experiences a positive pressure, increasing the net resistance of the pushrod moving into the lifter. Is this so far correct?
If so, when the engine shuts off, the supply of positive pressure has ceased, therefor it is just a matter of a few moments before equilibrium is restored inside the lifter and the only force acting on the pushrod cup is that of the spring force. Good?
If you were to push down on the lifter, you would still have some resistance against it, more than that of just the spring because oil is still inside the lifter, and it has to escape through the small oil passages, but once that is removed, only force available is that of the spring force. Good?
Is what I have thus far, good? I have more, but at the current time cannot remember, and this is a long enough OP for a non sticky technical post.
If I am thinking correctly, there is a spring inside the lifter beneath the pushrod cup. There are also oil passages, maybe of varying size for pressurization purposes? When oil pressure is up, the lifter experiences a positive pressure, increasing the net resistance of the pushrod moving into the lifter. Is this so far correct?
If so, when the engine shuts off, the supply of positive pressure has ceased, therefor it is just a matter of a few moments before equilibrium is restored inside the lifter and the only force acting on the pushrod cup is that of the spring force. Good?
If you were to push down on the lifter, you would still have some resistance against it, more than that of just the spring because oil is still inside the lifter, and it has to escape through the small oil passages, but once that is removed, only force available is that of the spring force. Good?
Is what I have thus far, good? I have more, but at the current time cannot remember, and this is a long enough OP for a non sticky technical post.
Any particular direction you might be headed with this?
03-01-2010, 11:54 PM
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just trying to further my understanding of engine dynamics, one small integral part at a time. So, the spring sits at the bottom of the inside of the lifter. A plunger is on top of that and sandwiched in between the cup. Does the plunger act like a piston in a two stroke and somehow regulate flow through the orifices or what? I had been trying like crazy to find a detailed and dimensioned sketch on the net of a hydraulic roller lifter, but I just realized I have my old LS1 lifters in the garage. I will bring to work tomorrow, tear it down and attempt to visually understand the dynamics.
