Replace or not to replace valve lathers and rollers
Well it started with doing a cam phasers job, once I got into it, found broken driver side guide, and frozen passenger side chain tension are, and gooped up sludge heads, cleaned up every thing, and popped off a cam to check last adjusters and rollers. I thought they are suppose to be able to press them down, all of the lashes are like no way to push them in, is that normal? Cam rollers spin okay. So question do I replace them and are they bad, what would cause this
FWIW I chose to replace ALL the lash adjusters & followers in conjunction with the chain / Phaser job on my '04 about four months ago, and I have never - for one second - regretted it. It had the signature 5.4L "tick" for practically all its 212,000 mile life before the timing chain job. Now, it is as quiet as a singer sewing machine.
IDK how lash adjusters can be "properly" checked or tested. You asked about 'depressing' the plunger. When they have OIL in them, it would be almost IMPOSSIBLE to depress the plunger all the way - even in a vice. But that is NOT the issue - as it would NEVER occur in normal operation. If you turn them upside down, you should be able to work the plunger up/down about 1/8" to 3/16" and cause them to '****' oil out of the hole in the side of the body. Then, if you turn them up right and press a piece of 1/4" plastic tubing against the side oil hole, when you blow and suck on the plastic tubing, you should be able to make the plunger pop up and down that 1/8" to 3/16" - without excessive force and without excessive loss of air or bubbling around the plunger shaft. AND THEN - if you press the 1/4" plastic tubing on the hole at top of the plunger and blow, you should be able to force a small amount of air through the lash adjuster - making very small bubbles of oil exit the side oil hole. (If either of these 'rudimentary' tests fail, I would not reuse the lifter. IMO, if one is replaced, I would replace ALL in a set.
A very small amount of (cranking) oil pressure must extend the plunger to take ALL the slack out from between the adjuster/rocker and the roller/cam and rocker/valve head. Running oil pressure must make A VERY small amount of oil exit the top and run down on the roller to be slung around on the cam lobe and valve head.
Basically - if the rollers have NO PITING, NO SLACK - UP/DOWN or SIDE TO SIDE and roll nice and smooth, they are probably OK. Again, IMO, if one is bad, I would replace all in a set.
On my truck, the rear ones (about 3) on the passenger side were very difficult to remove from their wells in the head. Had to use vice grips on them and vigorously twist them back and forth. I used strong solvents and compressed air in all wells trying to insure oil passageways were open and clean - and new ones dropped easily into the wells with oil holes lined up with oil holes inside the wells.
ABSOLUTELY no 'tick' or valve train sounds can be heard. Only the soft quiet clicking of fuel injectors. It is wonderful.