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Discussion Starter · #1 ·
Moved here, hoping somebody will see it

Quote, originally posted by Rippen Raymen »


things that can go wrong with it are some wear on top where it contacts the camshaft. also, it's a Hydraulic lifter, so basically its too parts. the oil goes into the hole and spreads the two parts so it makes a better contact with the camshaft. the thing is, the spreading is very minamal and if that stopped it wouldn't be a huge deal. like i said...some ticking...

From what you said it's that "Hydraulic" in the name means just the lifter is made of two parts, having oil between them? How's that making a lifter to have better contact with the camshaft?
Please, shed some light about Hydro lifters, that's the one of few things I still don't understand well.




Modified by dsimic at 9:41 AM 11-18-2004
 

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Re: Hydraulic lifters (dsimic)

If you look at the bottom side, there's a metal button sticking out up inside there. It is like a piston and it is what touches the end of the valve. The top surface touches the lobe of the cam. A solid lifter looks the same on the outside, minus the holes. On a solid lifter, you have to carefully adjust the clearance between the lifter and cam lobe so that it will open the valve fully but not bind as the metal parts expand. The hydraulic lifter eliminates this by taking up all the slack it can, by expanding (oil pressure fills the lifter and pushes the button out) but also being able to give as the parts expand. Hydro lifters are noisy until they are filled up, because of the excess valve clearances. Once they are pumped up, the valve train is hydraulically damped by the lifters, kinda like shock absorbers, and becomes very quiet. As lifters wear out, they fail to pump up fully and allow excess clearance between the parts. The ticking sound is the cam lobe slapping against the lifter and the lifter bouncing up and down on the valve stem, exaggerated of course. A collapsed lifter is one that won't pump up at all and allows extreme clearance such that the valve doesn't open fully. It would make a much louder "clack" sound. In essence, worn lifters are like worn shock absorbers.
 

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Re: Hydraulic lifters (A2B4guy)

Really GREAT explanation! Thanks A LOT! http://****************.com/smile/emthup.gif
Quote, originally posted by A2B4guy »
As lifters wear out, they fail to pump up fully and allow excess clearance between the parts.

Just to test my understanding: There has to be some kind of sealing (similar to piston and rings relation) between the metal button at the bottom side, and the rest of lifter's body, in order to make oil pressure push out the button; and that sealing is what wears out?
Do I sound correctly?
 
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