How to adjust rocker arms with hydraulic lifters?


These are the Chevy Rockers, if that matters. I found (somewhere, can't remember where) that I needed to go to zero lash, then give it 1/2 turn past that.

Well, turns out that since I have the intake and exhaust manifolds off I can see in there. It is very apparent that this process results in a couple of the valves being open, some up to what looks like 0.125"


Supporter 2018
Supporter 2021
Take each cylinder one at a time starting with #1
Turn the crank clockwise until the EXHAUST valve just begins to open and stop. Then adjust the INTAKE valve as you described with 1/2 turn past zero lash.

Now turn the crank clockwise again till the INTAKE valve opens and begins to close. Just as the intake valve closes stop and adjust the EXHAUST valve.

Continue the process on remaining cylinders 2,3,4,5 and 6.


Well-known member
Supporter 2018
old28racer":1t5wbg2a said:
Should this be done with the hydraulic lifters "dry" on the inside?

It can be done either way.

Pmuller9 wrote the sequence that will always work.

Now when you adjust, first have the rocker loose enough so the push rod and rocker is sloppy. Then tighten down while wiggling the pushrod lightly, just enough so that slop of the pushrod is taken up,
be sure you are not starting to collapse the lifter plunger.

Then, typically, tighten 3/4 turn more. If in any doubt, remove the side cover and be sure you are not collapsing the plunger before tightening the 3/4turn.