[Bigbore32]

I am confused on how lifters work, also what is the difference between solid and hydraulic lifters? And one more thing do hydraulic lifters have a cam in videos it doesnt look like they do please help!

[DoubleVision]

A solid lifter is just that, Soild. It's a solid piece of steel with a oil passage. Because it's solid, the lash has to be adjusted on the valve train to whatever clearance given by the cam maker.
Solid lifters have to have some lash as if they were set to zero lash like hydraulic lifters it would cause damage to the valve train as there is nothing there to compensate for it. Due to wear they also have to be readjusted in a given amount of miles. Solid lifter cams cause more wear faster, but they have a power advantage over hydraulic lifters.
Hydraulic lifters have a plunger assembly in the top. When the oil pressure comes up it pressurizes the plunger area so it rises until it hits a lock pin keeping it from going any further. The orifices in the hydraulic lifter are of small size so the oil does not bleed off too fast and cause the plunger to collapse. Hydraulic lifters you adjust once and let them ride, why is because the hydraulic action of the plunger creates a cushion for the pushrod to ride on and thus it can compensate in movement. In other words, once you adjust them they are self adjusting there after.
You can do a search on Google or yahoo or your perferred server and type in difference in solid and hydraulic lifters and likely find a better explanation than what I gave.
Your last question I don't know what you mean. They don't look like they have a cam? The cam operates the lifters, if there was no cam there would be no lifters either.

[Bigbore32]

kind of confusing but what i think i meant because on roller cams the cams are ontop of the vales ang push the valves in unlike the solid or hydraulic cams have lifters and the push rods work the lifters as well as the cam? i am not exactly sure how all of this works sense i am only 14 i am still trying to learn as much as possible

[my87Z]

I think you may be thinking over OHC engine when you say the cam is on top, OHC stands for over the head camshaft, many newer engines are like this such as the modular 4.6L and 5.4L ford V8's. All motors today use roller camshafts though. Take the Chevy LS motors, they use roller cams but aren't OHC motors, the still have the 1 cam located in the middle of the block above the crankshaft. The OHC motors have 2 cams, 1 over each head they even make DOHC motors which stands for dual over the head camshafts, these motors have 4 cams, 2 over each head. I hope this explains things a little bit for you.

[DoubleVision]

What you are referring to is overhead cams. Overhead cams don't have lifters as they are in direct contact with the rocker arms. Overhead cams also don't have pushrods. Roller cams are the same as solid and hydraulic types. Only on the bottom of the lifter there is a wheel hence the term Roller. There are solid roller cams and hydraulic roller cams.
I just did a search as I suggested to you and here is a site that explains it so maybe you'll understand it better.
Since your trying to learn my suggestion is get some books.
http://www.ehow.com/facts_7816973_so...c-lifters.html

[Bigbore32]

that makes alot more sense thanks for clearing it up for me