Editing Lifters
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− | [[File:Hydraulic Lifter.jpg|thumb|200px|left|Generic hydraulic lifter | + | [[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> |
==Overview== | ==Overview== | ||
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===Flat tappet=== | ===Flat tappet=== | ||
− | Flat tappet | + | Flat tappet lifters are flat on the bottom. Actually they're not perfectly flat, they have a very gradual radius ground onto them to help the lifter to rotate (along with the angle of the cam lobe), and resemble a cylinder of steel with a snap ring on one end holding in a pushrod cup. |
Flat tappet cam/lifter valve trains were the primary form of valve actuation for domestic engines from the early '50s until about the mid-'80s. They were reasonable durable and reasonably reliable, although there were better designs. Not until the EPA mandated a change in the motor oil formulations did they fall out of favor. | Flat tappet cam/lifter valve trains were the primary form of valve actuation for domestic engines from the early '50s until about the mid-'80s. They were reasonable durable and reasonably reliable, although there were better designs. Not until the EPA mandated a change in the motor oil formulations did they fall out of favor. | ||
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====Mushroom flat tappet lifter==== | ====Mushroom flat tappet lifter==== | ||
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Solid flat tappet lifters are still used in some high performance engines, solid roller valve trains are the choice for racing when allowed and street/strip engines used at high RPM. They are as durable as a hydraulic lifter in flat tappet form, but suffer the same wear problems due to the decrease of wear additives that have been removed from current motor oil. | Solid flat tappet lifters are still used in some high performance engines, solid roller valve trains are the choice for racing when allowed and street/strip engines used at high RPM. They are as durable as a hydraulic lifter in flat tappet form, but suffer the same wear problems due to the decrease of wear additives that have been removed from current motor oil. | ||
− | Solid lifters are not used in modern engines because they make enough noise that they could confuse knock sensors | + | Solid lifters are not used in modern engines because they make enough noise that they could confuse knock sensors. |
===Roller lifter=== | ===Roller lifter=== | ||
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Shown below is a GM hydraulic roller lifter. The arrow shows the location of the cup, spring and check ball assembly mentioned [[Lifters#Disassembling a hydraulic lifter|'''below''']]. | Shown below is a GM hydraulic roller lifter. The arrow shows the location of the cup, spring and check ball assembly mentioned [[Lifters#Disassembling a hydraulic lifter|'''below''']]. | ||
[[File:Oem hyd roller lifter expolded view.jpg|left|frame|OEM GM hydraulic roller lifter]] | [[File:Oem hyd roller lifter expolded view.jpg|left|frame|OEM GM hydraulic roller lifter]] | ||
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==How to tell a hydraulic lifter from a solid lifter== | ==How to tell a hydraulic lifter from a solid lifter== | ||
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The lifter is the most precisely machined part in the engine. The plunger OD is matched to the lifter body ID; the close tolerances are required to give the correct amount of bleed down. For that reason, there is a chance you might need to go through more than one lifter to find a good match to the old plunger OD. The MAIN thing is that the plunger 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 preferable to putting a new lifter on a used cam. | The lifter is the most precisely machined part in the engine. The plunger OD is matched to the lifter body ID; the close tolerances are required to give the correct amount of bleed down. For that reason, there is a chance you might need to go through more than one lifter to find a good match to the old plunger OD. The MAIN thing is that the plunger 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 preferable to putting a new lifter on a used cam. | ||
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[[Category:Engine]] | [[Category:Engine]] | ||
− | + | [[Category:Adjust valves]] | |
[[Category:Camshaft]] | [[Category:Camshaft]] |