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techtalk:evo:engmech02c [2022/09/05 05:19] hippysmack [Hydraulic Lifter - Mechanical and Hydraulic Operation] |
techtalk:evo:engmech02c [2024/01/03 19:51] (current) hippysmack |
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| ====== EVO: Engine Mechanicals - Sub-02C ====== | ====== EVO: Engine Mechanicals - Sub-02C ====== | ||
| ====== Hydraulic Lifter - Mechanical and Hydraulic Operation ====== | ====== Hydraulic Lifter - Mechanical and Hydraulic Operation ====== | ||
| + | The hydraulic lifters used in HD motors have about .200 of (useable) plunger travel ((aswracing of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-engine-conversions/59164-i-think-i-screwed-up-with-new-cam-install/page5?t=322680&page=5)) (about .230" if they bottom out, which is not good). \\ | ||
| + | As long as it's preloaded between about .050 and .150, it adjusts itself properly. So in other words, there's about a .100" range of pushrod length. \\ | ||
| + | The lifter will automatically adjust it's length to make it all work properly. \\ | ||
| + | |||
| System oil pressure goes all the way thru the lifters to the rocker boxes. \\ | System oil pressure goes all the way thru the lifters to the rocker boxes. \\ | ||
| However, system pressure at the lifter bore is restricted several times before it gets delivered into the pushrod tubes to the rocker arms. \\ | However, system pressure at the lifter bore is restricted several times before it gets delivered into the pushrod tubes to the rocker arms. \\ | ||
| Line 9: | Line 13: | ||
| Examining internal lifter oil paths from the lifter bore to the rocker arms will show some of these dynamics. \\ | Examining internal lifter oil paths from the lifter bore to the rocker arms will show some of these dynamics. \\ | ||
| - | {{:techtalk:ref:oil:1991-1999_sportster_lifter_body_internals_by_hippysmack.jpg?direct&400|}} ((photo by Hippysmack)) {{:techtalk:ref:oil:1991-1999_sportster_lifter_cutaway_by_hippysmack.jpg?direct&400|}} ((photo by Hippysmack)) \\ | + | {{techtalk:evo:engmech:1991-1999_sportster_lifter_body_internals_by_hippysmack.jpg?direct&400|}} ((photo by Hippysmack)) {{techtalk:evo:engmech:1991-1999_sportster_lifter_cutaway_by_hippysmack.jpg?direct&400|}} ((photo by Hippysmack)) \\ |
| + | \\ | ||
| Below is an animated drawing (.gif) of 1991-1999 Sportster lifter operation and oil feed. However, 1991-up lifter action are the same. \\ | Below is an animated drawing (.gif) of 1991-1999 Sportster lifter operation and oil feed. However, 1991-up lifter action are the same. \\ | ||
| - | It examples the test below in operation. \\ | + | It examples the text below in operation. \\ |
| + | |||
| + | Disclaimer: \\ | ||
| + | The main oil inlet in the lifter body has been moved from the from to the left side for clarity of the feed path. \\ | ||
| + | Also, the oil inlet is slightly lower than the actual part but operation and paths are the same. \\ | ||
| {{:techtalk:evo:oil:1991-1999_sportster_hydraulic_lifter_by_hippysmack.gif?direct|}} ((animation by Hippysmack)) \\ | {{:techtalk:evo:oil:1991-1999_sportster_hydraulic_lifter_by_hippysmack.gif?direct|}} ((animation by Hippysmack)) \\ | ||
| + | |||
| ====== Oil to the lifter body ====== | ====== Oil to the lifter body ====== | ||
| System oil pressure is fed through the lifter bores into the outer oil band that circles the lifter body. \\ | System oil pressure is fed through the lifter bores into the outer oil band that circles the lifter body. \\ | ||
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| In the drawing below, dims were taken from a 1998 1200S lifter and bore showing that oil feed is never blocked to the lifter. \\ | In the drawing below, dims were taken from a 1998 1200S lifter and bore showing that oil feed is never blocked to the lifter. \\ | ||
| The cams are Andrews N-4s so actual lift may vary. However, the feed hole in the bore should be the same for at least 1991-1999 Sportsters. \\ | The cams are Andrews N-4s so actual lift may vary. However, the feed hole in the bore should be the same for at least 1991-1999 Sportsters. \\ | ||
| - | {{:techtalk:ref:oil:1998_sportster_lifter_to_bore_feed_hole_relationship_by_hippysmack.png?direct&500|}} ((drawing by Hippysmack)) \\ | + | {{:techtalk:evo:engmech:1998_sportster_lifter_to_bore_feed_hole_relationship_by_hippysmack.png?direct&500|}} ((drawing by Hippysmack)) \\ |
| ====== Oil to the plunger reservoir ====== | ====== Oil to the plunger reservoir ====== | ||
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| The plunger is free to rotate invariably both during assembly and when not under load. \\ | The plunger is free to rotate invariably both during assembly and when not under load. \\ | ||
| - | {{:techtalk:evo:oil:1991-up_sportster_lifter_anatomy_by_hippysmack.png?direct&500|}} ((drawing by Hippysmack)) \\ | + | {{techtalk:evo:engmech:1991-up_sportster_lifter_anatomy_by_hippysmack.png?direct&500|}} ((drawing by Hippysmack)) \\ |
| - | ====== Roll of the check disc ====== | + | ====== Role of the check disc ====== |
| Sitting under the plunger is a thin metal disc with no holes in it that blocks oil from entering / leaving the pressure chamber below. \\ | Sitting under the plunger is a thin metal disc with no holes in it that blocks oil from entering / leaving the pressure chamber below. \\ | ||
| The disc has a spring below it and the spring tension comes from a metal cage that presses the assembly together. \\ | The disc has a spring below it and the spring tension comes from a metal cage that presses the assembly together. \\ | ||
| Line 64: | Line 74: | ||
| The downward force of oil in the plunger reservoir opens the check disc toward the lower chamber. \\ | The downward force of oil in the plunger reservoir opens the check disc toward the lower chamber. \\ | ||
| The (now open bottom) plunger is moving down into the lower chamber filled with oil. \\ | The (now open bottom) plunger is moving down into the lower chamber filled with oil. \\ | ||
| - | Some of the oil in the lower chamber is squeezed up past the open check disc into the plunger reservoir. \ | + | Some of the oil in the lower chamber is squeezed up past the open check disc into the plunger reservoir. \\ |
| With the check disc open, the lower chamber volume decreases as the plunger is continuously forced toward it by increasing engine valve spring pressure. \\ | With the check disc open, the lower chamber volume decreases as the plunger is continuously forced toward it by increasing engine valve spring pressure. \\ | ||
| This increases oil pressure in the lower chamber forcing the check disc to close toward the plunger. \\ | This increases oil pressure in the lower chamber forcing the check disc to close toward the plunger. \\ | ||
| Line 78: | Line 88: | ||
| This also re-sets the plunger height taking up the clearance between the pushrod and rocker arm creating zero lash. \\ | This also re-sets the plunger height taking up the clearance between the pushrod and rocker arm creating zero lash. \\ | ||
| - | ====== Oil to the rocker arms ====== | + | ====== Oil to the pushrods ====== |
| Oil is not allowed to simply flow straight through from the plunger reservoir up into the pushrod. \\ | Oil is not allowed to simply flow straight through from the plunger reservoir up into the pushrod. \\ | ||
| Sitting atop the plunger reservoir is a thin metal disc with 4 small holes (metering disc) drilled through it. \\ | Sitting atop the plunger reservoir is a thin metal disc with 4 small holes (metering disc) drilled through it. \\ | ||
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| And the pressure chamber is what actually raises the engine valves. | And the pressure chamber is what actually raises the engine valves. | ||
| - | {{:techtalk:ref:oil:1991-up_sportster_lifter_pushrod_cup_by_hippysmack.png?direct&500|}} ((drawing by Hippysmack)) \\ | + | {{techtalk:evo:engmech:1991-up_sportster_lifter_pushrod_cup_by_hippysmack.png?direct&500|}} ((drawing by Hippysmack)) \\ |
