Adjusting hydraulic lifters

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[[File:Hydraulic Lifter.jpg|thumb|200px|left|Generic hydraulic lifter]][[File:Schubeck hydraulic lifter made for zero lashing.jpg|thumb|150px|right|[http://www.schubeckracing.com/flathydraulic.html '''Schubeck hydraulic lifter'''] made to be zero-lashed]] <br><br>
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[[File:Hydraulic Lifter.jpg|thumb|200px|left|Generic hydraulic lifter]][[File:Schubeck hydraulic lifter made for zero lashing.jpg|thumb|150px|right|[http://www.schubeckracing.com/flathydraulic.html '''Schubeck hydraulic lifter'''] made to be zero-lashed]]
  
 
==Overview==
 
==Overview==
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==A word on the correct length pushrod==
 
==A word on the correct length pushrod==
To obtain the correct valve train geometry, the correct length pushrod needs to be determined and installed before setting the lifter preload. Below are some things to check that could have changed the correct pushrod length:
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To obtain the correct [http://www.crankshaftcoalition.com/wiki/Valve_train_geometry '''valve train geometry'''], the correct length pushrod needs to be determined and installed before setting the lifter preload. Below are some things to check that could have changed the correct pushrod length:
 
#Camshaft base circle diameter
 
#Camshaft base circle diameter
 
#Pushrod length due to wear or replacement
 
#Pushrod length due to wear or replacement
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#Valve seat height changes from seat replacement or from valve seat grinding/cutting done during valve jobs
 
#Valve seat height changes from seat replacement or from valve seat grinding/cutting done during valve jobs
 
#Grinding the tip of the valve stem when doing a valve job or different length valves
 
#Grinding the tip of the valve stem when doing a valve job or different length valves
#Lifter height due to different manufacturer
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#Lifter pushrod seat height due to different manufacturer
#Change in rocker arm type or design, or ratio
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#Change in rocker arm type, design, or ratio
  
 
==How much preload should I use?==
 
==How much preload should I use?==
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[[File:Wrenchturn.gif|border|150px|left]]
 
[[File:Lifter cutaway preload.jpg|border|400px|right]]
 
[[File:Lifter cutaway preload.jpg|border|400px|right]]
The recommendation given below to use 1/2 to 1 turn past zero lash is based on what has been shown to work well when using stock or performance hydraulic lifters. However, the amount of preload may be different, depending on the type and brand of hydraulic lifters being used. For example, there are Rhodes lifters that are set using a feeler gauge- something that's traditionally reserved for solid lifters. Always refer to the manufacturer's instructions first before proceeding. If the manufacturer's instructions differ from those given here, follow the manufacturer's recommendations.  
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The basic idea is to set the lifter plunger to the center of its travel. That gives the most leeway for temperature expansion/contraction. The amount of turns needed to set the plunger in the middle of its travel will vary from engine to engine because of differences in the thread pitch, rocker ratio, and lifter design.
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The old Chevy factory manuals said to use anywhere from 1 to 1-1/2 or more turns after zero lash, but this has largely been replaced by using 1/2 to 1 turn total. For instance, Comp Cams recommends 1/2 turn for regular SBC lifters.
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The recommendation given to use 1/2 to 1 turn past zero lash is based on what has been shown to work well on many engines when using stock or most performance hydraulic lifters. However, the amount of preload may be different, depending on the type and brand of hydraulic lifters being used as well as the reasons mentioned above. For example, there are Rhodes lifters that are set using a feeler gauge- something that's traditionally reserved for solid lifters. ''Always refer to the manufacturer's instructions first before proceeding''. If the manufacturer's instructions differ from those given here, follow the manufacturer's recommendations.  
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==Should I "pump up" my lifters with oil before installing them?==
 
==Should I "pump up" my lifters with oil before installing them?==
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==Can I replace a damaged lifter with a new lifter?==
 
==Can I replace a damaged lifter with a new lifter?==
[[File:Lifter expolded view.jpg|thumb|200px|left|Arrow points to check ball retainer]]
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;{{Note1}} See [http://www.crankshaftcoalition.com/wiki/Lifters#Repairing_or_replacing_lifters Repairing or replacing lifters]
[[File:Lifter clips 002.jpg|thumb|350px|Three styles of lifter cup retainers. The [http://www.truarc.com/pdfs/Truarc%20Catalog.pdf internal C-clip type] is stronger and should be used especially with solid lifters or when "zero lashing" lifters.]]
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Before replacing a stuck or noisy lifter (which should only be done as a LAST resort), disassemble the lifter that is in question. You will see a cup, spring and check ball retainer (left) snapped onto the bottom center of the "piston" of the lifter. Often all that has happened is the cup assembly isn't fully seated into the recess on the bottom of the piston, or a speck of dirt has lodged between the check ball and seat. <br style="clear:both"/>
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Remove the cup using a pick and see that the (tiny) spring and ball are there and that the ball isn't scored and that the seat on the piston that the ball seals, doesn't have any ridge or imperfections that would prevent the ball from seating properly.  
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[[File:Lifter expolded view.jpg|thumb|200px|left|Arrow points to check ball retainer on the end of the plunger]]
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[[File:Lifter clips 002.jpg|thumb|350px|Three styles of lifter cup retainers. The [http://www.truarc.com/pdfs/Truarc%20Catalog.pdf internal C-clip type] is stronger and should be used especially with solid lifters or when "zero lashing" lifters.]]
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When a lifter is noisy, often all that has happened is the check ball retainer assembly isn't fully seated into the recess on the bottom of the plunger, or a speck of dirt has lodged between the check ball and seat. This can be fixed, but requires the intake to come off to get to the lifter. Usually you can clean up the sludge inside the lifter using carb cleaner and it will perform fine again, but first check the surface of the lifter that faces the cam, if it's flat or concave just trash it, it must be sligthly convex.
  
Shown above, left, is a disassembled GM hydraulic roller lifter. Most current flat tappet lifters have the same internal construction as this roller lifter, although there are different styles. But as long as the styles are the same, the piston from one can usually be fitted into another body. The arrow shows the location of the cup, spring and check ball assembly mentioned above.
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Shown left, is a disassembled GM hydraulic roller lifter. Most current flat tappet lifters have the same internal construction as this roller lifter, although there are different styles. But as long as the styles are the same, the piston from one can usually be fitted into another body. The arrow shows the location of the cup, spring and check ball assembly mentioned above.<br style="clear:both"/> Details are at the page linked to above.
 
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A better choice if the lifter's piston is found to be unrepairable, would be to replace the piston from another identical lifter, and reuse the lifter body that has broken in to the lobe that it started life running on. The lifter foot and the cam lobe quickly wear in together to become a unit- using a new lifter risks wiping out the cam lobe. This is also why it is not recommended to replace a used set of lifters with a new set on a used camshaft.
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The lifter body ID and the piston OD are a very close tolerance fit- the closest tolerances in the entire engine. Because of this, there's a chance that one piston won't work the exact same as the original. As long as the piston doesn't fit too tightly, this won't be a problem in the vast majority of cases, but should be mentioned just the same. The clearance between the piston and body is what regulated the bleed down rate. But having a slightly different bleed down rate is much preferred over putting a new lifter onto a used cam lobe in this writers opinion.  
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===Chevy OEM hydraulic roller cam and lifters===
 
===Chevy OEM hydraulic roller cam and lifters===
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:*[http://www.crankshaftcoalition.com/wiki/Category:Adjust_valves Adjusting valves]
 
:*[http://www.crankshaftcoalition.com/wiki/Category:Adjust_valves Adjusting valves]
 
:*[http://www.crankshaftcoalition.com/wiki/Camshaft_install_tips_and_tricks Camshaft install tips and tricks]
 
:*[http://www.crankshaftcoalition.com/wiki/Camshaft_install_tips_and_tricks Camshaft install tips and tricks]
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:*[[Determining top dead center]]
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:*[[How to make a timing tape]]
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;Crane info:
 
;Crane info:
 
:*[http://www.cranecams.com/pdf-tech-tips/hydro-lift.pdf Fast and Easy Way to Check Hydraulic Lifter Preload when using '''Non-Adjustable Rocker Arms'''] from Crane.
 
:*[http://www.cranecams.com/pdf-tech-tips/hydro-lift.pdf Fast and Easy Way to Check Hydraulic Lifter Preload when using '''Non-Adjustable Rocker Arms'''] from Crane.
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[[Category:Good articles]]
 
[[Category:Good articles]]
 
[[Category:GM]]
 
[[Category:GM]]
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[[Category:Ford]]
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[[Category:MOPAR]]
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[[Category:AMC]]

Latest revision as of 20:09, 1 December 2014

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