Tried to set the valve lash on a used chevy 350 (rockers seemed loose) and discovered two of the pushrods would not move and the rockers would not stay on the exhuast springs. I tried to remove the pushrods and I couldn't get them to move or come out of the motor. A little back story.... my self proclaimed mechanical genious neighbor cranked down on them when I mentioned to him that they were loose without finding TDC or checking the pushrods for movement. I'm concerned the hydraulic lifters may have been ruined. Does anyone have any advice.  

pull the rockers off...  examine them...  see if the tip that contacts the tip of the valve stem is worn sideways....

is the top of the affected valves mushroomed...    rounded over...  

is the side of the rocker arm stud grooved...  where the edge of the slot wore into it...

if so... it will have to be removed...  if it does not have a hex on the base of the stud.. it is a pressed in stud....   warning... warning...   any tool that you use to pull the stud out has to be in full contact with all the threads on the stud...  not just a few...  see if you can rent the tool to extract them... or have a 3/4" fine thread grade 8 bolt drilled and tapped...  so you can use the external threads to pull the stud out...  more info if needed...

roll the push rods on something.. if they roll smooth.. they are ok... if they won't roll...  replace them....

it is really hard to destroy lifters from the top...    

so take it apart... see what you find... i mean the rocker arms off the affected cylinder...  not the entire motor...  

Sounds like he tried to set lash without the lifter being on the base circle of the cam.

It could be when he tightened down the rocker nut, he collapsed the lifter. It takes a lot (or a really massive screw up) to wear out a stamp steel rocker arm (if that's what you've got).

If the rockers are aftermarket, are they self-aligning? Or do the heads have pushrod guide plates?  

Also sounds like bent pushrods, which means its probably a good idea to pull the heads and check the pistons and valves for contact damage.  

Good info , thanks
I'll work on it this weekend and get back to ya. The motor hasn't benn turned over since I found this problem so I'm hopeful that whatever the problem is it shouldn't be to bad........I hope...knock on wood.  

OK, pulled the intake off and discovered the valves in question had bent pushrods. One of the lifters still had spring in it's step but the other one seemed pretty stiff. A friend suggested I soak it in oil overnight to see if that will help. What do you guys think? Will it be alright? Do I just need to replace the 2 bent pushrods with some I've got layin around the garage or do I need all new ones? Or should I replace the cam, lifters, rods and maybe put in some rollers?  

if they are straight... and have undamaged tips.... and are clean inside... use them;

roll them together on something flat... you will be able to tell if one is bent...

as for making sure they are clean inside... soak them in some water based cleaner... i try to use smart and finals... heavy duty cleaner degreaser..  sort of like fantastic or 409 but much stronger...  then wash them off in hot water and air dry.. look through the pile of them to see if you see light through the end of the pushrod...

as for the lifter that has spring in it...  it just might be empty...  all the oil forced out of it by the misadjusted rockers ... or that on was at the top of the lobe ...



did you examine that top of the valves...   the tip... is it still square... flat on the end... or is it curved, rounded over..?????

did you examine the sides of the rocker arm stud?????     about 1/2" below the bottom of the threads?????   side loading of the rocker arm wears grooves in the side of the studs...   when it gets deep enough... the rocker arm falls off the top of the valve.. and it bends the pushrod... i have seen this hundreds of times in motors that i have taken apart....  

as for changing out the cam and lifters... that is totally up to you...

if the cam has performed up to what you expect ... and it is not damaged... just put some new pushrods... and reuse it......

warning... if you pull the lifters out... they have to go back in the same exact hole....     failure to do this on a broken in cam... will cause the cam and lifters to fail...  in most cases.. roller lifters not included...  

The two pushrods were bent and twisted so there was no doubt they were bad. I'll look at all the other warning signs you pointed out. Thanks for info, by the way, the motor has been run but not for awhile(1 year). When I bought it it was supposed to only have 5000 miles on it. The one time we had it running every thing seemed to be running great so I'm left to wonder if those two pushrods got damaged from just being over tightened?