Lifters

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(Add text, images, link; clean up)
(Replacing lifters: Add text; minor clean up)
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[[File:Lifter expolded view.jpg|thumb|200px|left|Arrow points to check ball retainer]]
 
[[File:Lifter expolded view.jpg|thumb|200px|left|Arrow points to check ball retainer]]
 
[[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.]]  
 
[[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.]]  
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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{{Caution}}Lifters and cam lobes become wedded as soon as the engine fires up and the cam is broken in. From that point forward, the same lifter '''has''' to be kept on the same lobe, preferably in the same engine. To replace a faulty lifter with a new lifter (or to replace a used cam with a new cam, reusing the same lifters) is to ask for a catastrophic failure requiring the engine to be torn down to remove the shrapnel left from the destruction of the cam lobe(s) and lifter(s).<br><br>
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Before replacing a stuck or noisy lifter with a new lifter (which should be considered only in an emergency situation), 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"/>
  
 
Remove the cup using a pick and see that the tiny spring and check 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.  
 
Remove the cup using a pick and see that the tiny spring and check 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.  
  
A better choice if the lifter's bore is OK but the piston is found to be unrepairable, would be to replace the piston (from another 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.  
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A better choice if the lifter's bore is OK but the piston is found to be unrepairable, would be to replace the piston assembly from another identical lifter and reuse the lifter body, then replace the lifter back on the same lobe it came from.
[[Lifters#Roller lifter|'''Return to top''']].
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{{Note1}}The lifter is the most precisely machined part in the engine. The piston OD is matched to the lifter body ID, the close tolerances are required to give the correct amount of bleed down. For that reason, swapping out the piston from one lifter to another will not always work, so plan on having to go through more than one lifter to find a good match to the old piston OD. The MAIN thing is that the piston not be too tight. Slightly loose will still perform OK, although there's a chance there could be some slight tapping at idle. But if the lifter and cam cannot for whatever reason be replaced as a set, this is STILL preferrable to putting a new lifter on a used cam.  
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*[[Lifters#Roller lifter|'''Return to top''']].
  
 
[[Category:Engine]]
 
[[Category:Engine]]
 
[[Category:Adjust valves]]
 
[[Category:Adjust valves]]

Revision as of 18:33, 3 July 2012

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