Topic: Valve adjustment

[Keith]

There seems to be a lot of confusion when it comes to basic mechanical work, such as valve adjustments. I made a rough sketch to help explain how a valve train works, and what position the cam (s) must be in order to adjust properly. In the top image, the cam lobes are facing down, away from the rocker arm assembly. There will be no pressure against the valve stem, and the valve can be adjusted. NOTE: just because this may be #1 cylinder, and the piston is at the top of the stroke, it does not mean you are on the compression stroke! It is, after all, a 4 stroke engine. There are four possibilities: both valves closed, intake valve closed, exhaust valve open. Exhaust valve open, intake valve closed, both valves open. You must be on the correct stroke.
The bottom image shows the cam lobe hitting the rocker arm, which pushes the valve open. You CANNOT adjust the valves in this position. How can you tell?  One example, rotate crank to T1and 4. With the valve adjustment caps removed, check for play at the rockers: Either cylinder 1 or 4 should have play at the rockers. Adjust those valves. Now, rotate engine to T1-4 again...one rotation. Adjust the other pair of valves for that cylinder. Now, rotate crank to T2-3. Follow the same procedures.
If you are still not sure, have someone rotate the crank while your finger is on the tip of the rocker....you will feel it move up or down. When it reaches the top, you should feel free play, and the crank should be at one of the T marks.

[Keith]

One thing I forgot to mention....pairs of cylinders DO NOT fire at the same time. In other words, if you set valve clearance on cylinder one, you cannot adjust valve on cylinder 4 at the same time! You must rotate the engine again until T 1-4 lines up and the valve on cylinder 4 have free play.

[kmb69]

VERY GOOD!
Explanation doesn't get much better than that.
Only thing that might be added is, if a valve or valves are already adjusted too tight, you might not be able to feel 2 loose rockers for that pair at TDC. But you should be able to observe if both rockers are in the UP position at their particular timing marks.

And unfortunately, you probably gonna need a valve job if that condition exist. 

[DaveBarbier]

I like that too, I'm saving this image.

[dave500]

remove all the caps and rotate the engine in the direction it runs,watch as any of the intake valves start to close,once closed look at the timing marks and watch as the very next "T" mark comes into view as you continue turning and it aligns with the case mark,set that valve pair and continue through them all.too easy.