How do I tell if my hydraulic lifter's are ok?

[simon]

Too many problems to go into here, but how do I tell if my lifters are no good (I think I may have one that's collapsed and rattling)
I'm going to take them out of the engine one at a time, dissasemble and clean them but how will I tell if they are no good? should I be able to blow through the lifter from the side hole and have air come out through the top hole? how about vice versa?
Thanks guys any advice you can give will help stop my driving my Cobra to the crusher!
Simon
ps 400 mile engine, Edelbrock performer plus cam with hydraulic lifters, oil changed 3 times already


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[GUMBALL]

Hi Simon,

Sorry to hear you still haven't found the problem.
I would be tempted to send an e-mail to Crane, Compcams & probably Edelbrock too, and ask them the best way to test a lifter. Don't know about Crane & Compcams, but Edelbrock come back within a day usually - may be worth a try.

Good Luck

GUMBALL x(

[ian]

Hello Simon, I have been following your case with interest, hope you get to the bottom of it soon. The first and most obvious thing to check is the face where the lifter slides on the cam lobe - these apparently should be very slightly convex. By comparing all 16 faces you may find one which is different. If there is a dodgy one then you would have to suspect a cam lobe aswell. The lifter internals generally only wear out if the engine is run for lengthy periods with dirty oil. Sometimes lifters can 'stick' if some crud gets in there, so they appear solid. You could check that the pressure required to push the lifter in is the same in each case. If there is a sticking one it should be obvious, as should a collapsed one where it has gone back into itself and offers no resistance before hitting the bottom. The holes are there for bleed purposes and I think also to oil the pushrod. Do your pushrods oil the rockers? If so check that they are not blocked. Can't think of much else, hope it's not the cam. Good luck. Ian.

[callum]

In lay terms the hydraulic lifter is basically a bucket with a lid. Underneath hides a coil spring trying to push the lid off. The lid is kept in place by a circlip. The spring is not quite strong enough to actuate the pushrods on its own. It needs hydraulic assistance from the oil in the bucket to stop the lid getting getting depressed between the rising cam lobe and (via the rockers) the resisting valve springs. The correct oil level for this 'hydraulic assist' is maintained in the lifter by the bleed hole (which also helps lubricate the bore in the block it sits in.) Crudely, when the engine runs, the excess oil draining into the lifter lid gets squirted up inside the hollow pushrod (as the lid collapses slightly) thereby lubricating the valve gear while oil inside the lifter goes out of the bleed hole.
So, you might have a broken spring that only a strip down of the affected lifter will reveal. Chevys more commonly wear the cam lobe and this would probably show on the bottom of the lifter as pitting. The surface is not flat as it appears but dished so that it rotates slightly under the action of the cam shaft. A dial guage would reveal any loss of lift by measuring the valve stem movement. As has been said, only prolonged use on dirty oil would cause a problem unless the cam break in was not done properly or you've had a mechanical breakage inside the lifter. What exactly are the symptoms?

[JimT]

This might be of some help:

http://www.compcams.com/Community/Ar...asp?printer=1&

Jim.