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techtalk:evo:engmech02c [2022/09/05 05:33] – [Hydraulic Lifter - Mechanical and Hydraulic Operation] hippysmacktechtalk:evo:engmech02c [2024/05/22 04:33] (current) – [Hydraulic Lifter - Mechanical and Hydraulic Operation] 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. \\
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 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. \\
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 Disclaimer: \\ 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. \\+The main oil inlet in the lifter body has been moved 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. \\ 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. \\
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 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. \\
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 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)) \\
  
  

Trace: • EVO: Engine Mechanicals - Sub-02C