Originally Posted by DevilDogDoc
They adjust themselves hydraulically. You cant adjust them but you can replace the lifters AND CAM if they are going bad.
This above after I fixed it. lifters and cam must be replaced as a set. If the old ones were taken out and not put back in right hole they will eat the cam and them selves up.
There is no adjust ment for them. Engine oil pumps them up.
but you may have a bigger issue.
1. High or low oil level in crankcase 1. Check for correct oil level. Adjust oil level by draining or adding as needed
2. Thin or diluted oil 2. Change oil
3. Low oil pressure 3. Check engine oil level. If ok,
Perform oil pressure test. Hook a manual pressure gauge to fitting on block.
4. Dirt in tappets/lash adjusters 4. Clean/replace hydraulic
5. Bent push rod(s) 5. Install new push rods
6. Worn rocker arms 6. Inspect oil supply to rocker arms
and replace worn arms as needed
7. Worn tappets/lash adjusters 7. Install new hydraulic tappets/lash adjusters
8. Worn valve guides 8. Inspect all valve guides and
replace as necessary
9. Excessive runout of valve seats or valve faces 9. Grind valves and seats