I just got my 96 z28 engine rebuilt and I am now having problems adjusting the valve lash. If need to know there is a 306 cam in the block. I am using shbox's recommendation on how to do this. Anyhow on most of the exhaust rocker arms I would be able to tighten the rocker arm all the way down and still would not be able to get the pushrod to drag and yes I would start to tighten the exhaust rocker arm after the intake valve opened all the way and then was almost all the way back up.(matter of fact I would let the intake close completely and I would then just counterclockwise the crank to open the intake back up just barely) I am almost positive I did all these the same way as shbox said to do it. I will check again but can someone give me a possible reason why this could be happening.

 

If you have the adjusting nut completly tight, and there is no drag on the pushrod, something is definatly not right. Sounds like the pushrods are too short, or else you didn't get the other end of the pushrod on the lifter. Are you doing this in the car with the intake still on the motor?

 

The intake is off. The motor isn't actually in the car yet. Before I say anything else is it ok to do this valve adjustment without oil? I of course have lube over every single part of the engine. I just didn't know if the lifters are suppose to be full of oil yet.

Also I think I got it figured out. There is a little nut inside of the nut that tightens down the rocker arm and on some of these the little nut was already tightened and it wouldn't let me tighten the nut that tightens the rocker arm down(that probably sounds so confusing). Anyway I loosend this little nut on all of them and I am fixing to try and redo it

 

So the allen head lock on your polylocks was locked eh? That'll do it. Glad you got it figured out

 

Can you help me with one thing? Is it ok to not have the oil in the motor yet to do this adjusting? I have lube over everything.

 

Yes, but it would be best if you dumped a quart or two of oil in the lifter valley over all the lifters and let them get at least a little oil in them so they pump up faster when you start the engine. Otherwise they will clatter for a while until they all get full of oil, even if you have them adjusted properly. Hope this helps

 

It was definantly the locks. I will make sure to dump oil over the lifter valley. Thanks alot for all your help.

 

With the intake off and no oil it is easy. First get the engine set on #1 back off the rockers until ya got slack,tighten them spinning the pushrod and watching the lifter cap. When the cap moves down from the lock that is "drag" feeling when ya spin the pushrod. Back it up and watch the cap,when it "just" moves that is "0" then go 1/4 turn more and lock it down.Do the other one on that cyl and go to the next cyl in the firing order 1-8-4-3-6-5-7-2. Get each cyl on TDC by sticking your finger in the hole and listen for the woosh and go until the sound get's louder if the sound starts to get softer ya gone to far--back it up. Do um all like that and make sure your locks are good and tight and ya are done. It will be fine after it cranks. Prime the engine with a priming tool and a drill before cranking and do it long enough to get oil to the rockers. I hoped they used assy lube, with assy lube it will be fine but to be sure(if ya don't know) prime it before turning to adjust valves,don't want to hurt the brgs.