General question here I hope. I'm helping a buddy adjust the rockers on his 1996 Chevy 350. It's an Indmar Inboard Marine engine but I'm guessing the same rules apply.

So we had a blown head gasket and pulled both heads, had everything checked and replaced both gaskets.

The lifters weren't taken out so they still have oil in them.

My question is: Do I adjust the rockers to just remove the valve lash (pushrods spin but no vertical movement)?

I've seen some talk about removing all the lash while rotating the engine in 90 degree increments, 8 times for a total of 720 degrees. Then tighten another 3/4 turn on each rocker to set the pre-load on the lifters @ .030". But if the lifters weren't removed, do we need to set the pre-load, or is zero lash the way to go?

Thanks,

RickR90s

 

I'd have replaced the lifters (you can pre-charge them with motor oil before installation, real easy) Did you inspect the push-rods for any blockages and or sludge inside?.

To achieve zero lash, tighten down the rocker as you spin the push rod in your fingers, do this until you notice slight resistance as you spin the pushrod (that's zero lash).

You should also no longer have any lateral movement of the pushrod. When you know you’ve hit zero lash, tighten the rocker another 1/2 to 3/4 turn to set the optimum preload on the lifter, push-rod and rocker arm.