collapsed lifter (definition)
lots and lots of carbon buildup thoumy question is that I understand Part of the concept of the Hyd lifters, they are some sort of a captive piston controlled by oil presurre and the area of the piston is just enough for NOT to lift the valve under relaxed state and oil pressure, and the compressing force is managed by a some sort of check valve.
how if the liftert floats the check valve opens to close the valve, or the lifter stays elongated beyond openning distance permanently.
if a lifter "collapses" it is correct that the seal created betwen the piston-cyl inside the lifter, or the check valve are compromised.
My lifters about ten of them are free moving (with my finger in the cup they move about 1/8" with little spring resistance, the rest are definetelly harder to move but non the less they move under finger pressure.
it is possible to clean the inside of the piston assembly in case of debris inside? taking the square snap "ring" (square) from the top of the lifter.
(see, less smily faces!)
You know, the Comp 850s are cheaper than the stock lifters and far better.
Dixit
Dixit
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To me having a solid lifter sounds better and less of a headache but dont get why hydraulic is the way to go for quiter valvetrain and supposedly less harsh on valvetrain and cam.
Thanks for taking the time to explain how it works.
Dixit
In a hydraulic lifter, the plunger can move up and down a small amount within the lifter.
Engine oil pressure forces the plunger upward, but forces from the valvespring, carried through the pushrod, force the plunger down.
As a result, the plunger absorbs shocks and eliminates clearance in the valvetrain.
With hydraulic lifters, valve lash is not necessary as long as lifter preload is adjusted properly.
Engine oil travels through mechanical lifters as well, but the lifter acts only as a conduit to carry oil to the pushrods, which transport the oil up to the rocker arms.
When we talk about preload I understand most of it there, but say you take a LS6 stock block, and I replace the stock lifters with CompCams oem replacement onces, how do I make sure the preload is identical? Plus how can I adjust it if the lifter is not adjustable and the ls6 rockers are not adjustable either?
Im learning a good bit here. Keep it coming Predator-Z
Dixit
Idealy they will all be different length, but going to the closest .05" is OK since the lifter absorbs the minute differences.
That is why adjustable rockers get you a more accurate preload and are usualy quieter if properly done.
A dial is used to measure preload or there is the old marking the p-rod method and measuring the drop difference.






