340 issue after camshaft change

This is how I always do it. For me it's just simpler. I copied this info. a while back as my memory sucks these days lol.


Valve adjusting



This procedure is generally called the EO/IC method, which stands for exhaust opening/intake closing. Working with the first cylinder turn the engine until the exhaust valve starts to open. That indicates that the intake valve is resting fully on the cam base circle and can be adjusted. Then turn the engine over until the intake valve is just about to close. That means the exhaust valve is ready to be adjusted. Simply repeat this process with all remaining cylinders.

The process is slightly different with hydraulic lifters. There is no gap to set; rather, the lifter needs a “preload” to ensure that the plunger is in the center of its travel. Basically, the pushrod is rotated with one hand and the rocker arm is tightened until the pushrod is snug in place or at zero lash. Then the adjuster is turned or tightened until there is enough preload. The amount the adjusting nut is turned depends on the type of adjustment mechanism as well as the lifter. Most applications will use a 7/16-20 rocker-arm stud. A full turn of the adjustment nut moves the rocker .050-inch, so a quarter turn will provide .0125-inch preload in the lifter. The adjustment on the pushrod end of the rocker arm can be calculated in a similar manner. Jesel uses a 3/8-24 screw adjuster, which equates to .041-inch movement with each full turn.
There could be an issue with your term snug. People have different interpretations of what snug means. What I do is turn the adjuster down so the pushrod still can be lifted up and down slightly (say 1/32"). At this point your index finger gently on the side of the pushrod and moved back and forth will easily turn the pushrod. Turn the adjuster down until that easy rotation stops. At this point there is zero lash but the hydraulic mechanizm is not being pushed down. Now the prescribed 1/4 to 3/4 turn on the adjuster can be made to position the lifter piston in the center of its travel.
If the snug interpretation is the pushrod can not be rotated using a finger and thumb, the lifter is probably collapsed to the bottom. Then the preload 1/4 to 3/4 turn is opening the valve.
Personally I prefer the 1/4 turn as it moves the piston down slightly allowing the lifter to function as designed, but not much for pumpup on high revs. If you do get to the pumpup state, power will go flat.