Probably about time-rocker adjustment
remove the valve cover and then remove the rocker shafts (loosen each bolt a turn them move to next one starting from the center and moving out, unti they are all out. You dont want to loosen them all and have one end still holding tight as it could damage the shaft) and then remove the pushrods (keep in order). Look down into the lifter with a flashlight. If it has a circlip or a wire retainer at the pushrod cup, its 95% chance a hydraulic lifter. If it has no clip whatsoever, its a solid. Solids need lash when the valve is UP, and it can only be measured when the lifter is on the base circle of the cam lobe. Hydros need to be sunk into the lifter about .060 at same cam base circle position. you do that with the adjuster. It will be fighting a spring in the lifter so you may or may not be able to spin the pushrods when they are under hydraulic preload. You can also tap the rocker with motor turned off and at rest for at least 10 minutes with a mallet under load and if it gives a little, that could point to a hydraulic. If the pushrods are turning while the motor is idling, that is a good thing as the rockers are doing what they were designed to do, rotate with the crown of the lobe tip. That keeps wear to a minimum. Solid and a hydro, note the retainer clip on hydro
remove the valve cover and then remove the rocker shafts (loosen each bolt a turn them move to next one starting from the center and moving out, unti they are all out. You dont want to loosen them all and have one end still holding tight as it could damage the shaft) and then remove the pushrods (keep in order). Look down into the lifter with a flashlight. If it has a circlip or a wire retainer at the pushrod cup, its 95% chance a hydraulic lifter. If it has no clip whatsoever, its a solid. Solids need lash when the valve is UP, and it can only be measured when the lifter is on the base circle of the cam lobe. Hydros need to be sunk into the lifter about .060 at same cam base circle position. you do that with the adjuster. It will be fighting a spring in the lifter so you may or may not be able to spin the pushrods when they are under hydraulic preload. You can also tap the rocker with motor turned off and at rest for at least 10 minutes with a mallet under load and if it gives a little, that could point to a hydraulic. If the pushrods are turning while the motor is idling, that is a good thing as the rockers are doing what they were designed to do, rotate with the crown of the lobe tip. That keeps wear to a minimum. Solid and a hydro, note the retainer clip on hydro
