W123. Adjusting Valves the easy way. Advise from a Mercedes master to an apprentice - PeachParts Mercedes-Benz Forum

Hip001 · #1 07-07-2013, 11:56 AM

My first time adjusting valves. 2.5hrs taking my time to adjust and recheck. Used the regular way due to the fact I didn't have a wrench to hold the large nut. All 8 valves were tight. I did have a issue re-installing the valve cover. then found out the cam was in the wrong position not allowing the cover to slide by. once i rotated the motor it went right on.
Seems to start and run smoother.

ROLLGUY · #2 07-07-2013, 02:32 PM

Quote:

Originally Posted by Hip001

My first time adjusting valves. 2.5hrs taking my time to adjust and recheck. Used the regular way due to the fact I didn't have a wrench to hold the large nut. All 8 valves were tight. I did have a issue re-installing the valve cover. then found out the cam was in the wrong position not allowing the cover to slide by. once i rotated the motor it went right on.
Seems to start and run smoother.

I have found that after doing the valves in the firing order, the valve cover just falls into place after adjusting #3 (5 cyl).

Fattyman · #3 07-07-2013, 08:16 PM

I dunno about this. It would seem to me that jam nuts are designed to be tightened to prevent movement. And then loosened to allow movement. It's not that big of a deal really. Just adjust each valve as the lobe points to the oil rail and move on. Keep it simple. That's why the valve adjusting wrenches come in a set of 3. Use them

rscurtis · #4 07-08-2013, 08:22 PM

I would have to agree. Any time saved will be long gone after you strip the threads on one of the valves.

klei9843 · #5 08-25-2016, 06:01 PM

This is complete nonsense. It's been a few years, so hopefully you found another mechanic... Let's simplify:

Look at the design of the valve. Effectively, you have a threaded rod (valve stem) going through a hole in a cap that can spin (the part over the spring with the hex flats). You can rotate the cap infinitely, which rotates the entire valve as well. The only way to affect the position of the valve stem relative to the cap and the rocker is to turn the lower nut, which requires loosening of the upper one. If you rotate the locked valve nuts relative to the cap, spinning the entire valve, you are doing nothing. At best you are grinding the valve against the valve seat, which might knock some debris loose. Take a look at the design drawing.

leathermang · #6 11-01-2016, 11:34 AM

Quote:

Originally Posted by klei9843

..... If you rotate the locked valve nuts relative to the cap, spinning the entire valve, you are doing nothing. At best you are grinding the valve against the valve seat, which might knock some debris loose. Take a look at the design drawing.

If you look at the design drawing below the spring... you will see a valve rotator..... which is always rotating the valve as the engine runs... keeps the valve and valve seat round.... and means turning the valve by hand has no chance of ' knocking ' some debris loose.