It just started pulled the valve cover spring CC918 appears OK. However spring & rocker arm intake side #3 cyl has alot of vibration in it. It also has a slight hesitation but not missing. Cam is a CompCam 224/228 581/588, Heads are LS6 stage II, push rods are chrome moly 7.350, lifters are stock.

 

Nobody has advice or had this problem? I am thinking it is a lifter going south I pulled the springs yesterday all in order. Put it back together and it seems to et worse when it warms up just above idle.

 

You could go back over all of the rockers and retorque them checking for the correct preload. Maybe #3 cylinder doesn't have enough preload.

 

Check the sides of the rockers and make sure the caps are still on them. If some of the bearings spill out it'll do something similar to what you are describing.

 

I changed the rocker arm still have alot of vibration in the #3 intake spring and rocker arm I started it with the valve cover off sounds and like a lifter sending the vibratin up the push rod to the rocker arm and spring. I do not wanna hort anything just did a rebuild on the bottom end it was running good 11.8 N/A It seems to be loosing power and skipping missing once in a while and the valve train used to sound like a sewing machine now ist sounds like a weed eater cutting grass hitting rocks. Engine is starting to shake more than normal at idle also. I am not driving it but I really do not wanna pull the heads unless I am sure. Plug #3 is running rich pretty Black and the tach just went out.

 

Any body know could this be a bad lifter? Oil pressure is good. Spring and rocker arm have a vibration I have inspected push rod rocker and spring however it starts to clack off idle intake side only. There is a slight hesitation sometimes also. I really do not want to pull the heads unless I have to. I am running 7.350 push rods that made the valvetrain louder also.

 

Its hard to diagnose something over a computer. But, it sounds like a collapsed lifter. Same discription of what a friend of mine went through. We ended up pulling the heads off, and sure enough, thats what it was.

 

FWIW It was a lifter.