Hello everyone, I just did a head gasket replacement on my 92 S-10 Blazer Vortec 4.3. I am in the process of reassembling the engine and I have a #3 cylinder valve thats not adjusting properly. I am following the Hayne's Manual instructions for proper valve adjustment (tightend the valve till no play then an extra half turn), the valve will only turn about 1/4th and it is too tight. I am new to valvetrain adjustments but there is something wrong and I have no clue what it is. After getting the Haynes Manual I learned all of the pushrods need to go back in the way they came out, I did not do this, could this be the issue? Any help would be appreciated.

 

Can't edit my post but it is the #2 cylinder exhaust valve if that matters.

 

Push rods should all be the same. They should go back exactly where they were, although I've seen many engines run fine when they weren't. The lifters themselves would be more critical as to original placement. (camshaft wear etc)

Now, I'm assuming you're adjusting the valves with the engine not running.
I would guess that the pushrod is not seated on the lifter. Then it definitely would be tight. Good way to bust something. Could be resting on the oil galley casting. Or, the lifter is in upsidedown. (extremely slim chance, but possible. Doubt you would get the pushrod in place then).

How does the height of the stud threads compare to the others?

Measure the threads left showing on the stud. Remove nut, ball, rocker arm, turn nut down on stud to see if it could go down further. Maybe stud pulled out of head. (They're pressed in, I think). Highly unlikely, but...... Are the threads OK? Measure height of another stud.
I'd bet that the push rod is not seated on the lifter. Easy to do.
Or a collapsed lifter.
Jeez, I keep thinking up more stuff!! I'm getting a headache.

 

The pushrod is seated on the lifter properly and works fine turning the engine by hand, so the lifter isn't collapsed. The stud thread seems to be fine also.

 

This makes no sense.

IF it were mine I would use a wooden dowel (or pushrod itself), stick it down the hole to the lifter, see if the lifter can be compressed with hand pressure. Should be able to tell. Try a different pushrod/lifter. See if it takes the same effort.

If same; then I'd check the stud.

 

could be that the cam is starting to open the valve and if thats the case than you have to rotate the engine because you cant adjust valves when they are open HAVE to be closed. just what it sounds like to me.

 

That was my thought too, but the engine can be turned by hand so I assume that is how they all are being adjusted. And why just 1/4 turn? Should still be able to adjust it more than 1/4 turn, even with the valve open. And, then, there should be more than just the one.

Hard to diagnose with eyeballing it.

 

I have a feeling you are trying to adjust the valve that is open. Rotate her by hand a little and try again to make sure its closed.

Next time you take apart a valve train, mark all the parts as to wehre they came from, or put them down in order to make sure they go back where they came from... Most guys make holes in a cardboard box to stick the pushrods in, and then drop the rocker arms down the pushrods in the ordr they get put back in. That ensure the parts go back on where they came off. diff parts wear at diff rates.

I doubt this is your problem. Try rotating the engine a little and see if you can get your proper adjustment.