Thread: valve adjustment

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Another question on this 454. While adjusting "zero lash" I've read tighen down on the rocker while rotating the push rod until there there is slight resistance and then go about 1/2 a turn more. Not sure if I can discribe this right but if you can push down on the push rod and there is a little spring back do you adjust down until the spring back is gone and then go another 1/2 turn? Should there be any spring back? In other words it seems like when I push down on the push rod it is compressing the lifter.

The short answer is no. If you eliminate what you call "the spring back," you'll lock up the lifter and can cause interference between the valve head and the piston. Not a good thing.

BTW, I don't believe in the "rotation" method. I move the pushrod up and down as I tighten the nut until I can feel no slack. I don't believe in the rotation method. It depends too much on feel to determine the "slight resistance." Slight means different things to different people.

Thank you for the advise!

Originally Posted by DennyW

((I've read tighen down on the rocker while rotating the push rod until there there is slight resistance and then go about 1/2 a turn more.)) That way is fine, but I like to feel the play by feeling the gap between the rocker and the valve. The reason is just what you have said ((Not sure if I can discribe this right but if you can push down on the push rod and there is a little spring back do you adjust down until the spring back is gone and then go another 1/2 turn?)) That is because your lifters are not pumped up with oil, and a mistake is about to happen. That springy part is just that. Zero lash means without compressing the the lifter at all. This is hard to feel by spinning the pushrod.

I like to take 2 fingers with one hand, and move the rocker up and down to feel the gap, click of the rocker, until I get all the play out. That is zero lash.

ps: What Jack said above.....

i done it dennys way to and i done it like Jacks way a bit of both i know guys that will go a full turn i do not. on any engine with out a non-adjustable valve train that i mill the heads block valve job cam re grind or re arc the rocker arms or thicker head gaskets. i do with intake off and a wire feeler gage between the clip in the lifter and the push rod cup if to much i shim the rocker stands or use adustable push rod or make the valve train adjustable. i take alot of time doing this do not rush thru setting valves . i always mark the rocker after the lash is set with a marker so if you walk away or the phone rings and go back you know were you left off i find the older i get the more i do this i mark every thing.. i have walk around the shop looking for wrench only to find it is in my hand