Valve adjustment question for m110 engine

[beagle2022]

I have just done my second valve adjustment on my 1979 280sel in six months. Not my favourite job, but not too bad.

My question is, why did I need to do it after about 2500km's since the last adjustment?

When adjusted the old girl runs smoothly and sounds tight.  But it doesn't stay that way for long and the sewing machine noises start again. The car is used mainly for motor way driving at about 110kmh with a little suburban pottering in between.

The engine has done 294k kilometres.

Do I need to get fresh spring clips? Is there some trick that I don't know?  Is it just part of the turf with an ageing car?

[adamb]

That's deffo too frequent. New clips should make things better.

[dima]

What is the gap is in the valves? 110 motor clearances on the increase and the hot engine is louder than it normally

[dima]

On a hot engine clearances are greater.  inlet:  cold. 0.10 mm,  hot. 0.15 mm.  Issue:  cold. 0.25 mm,  hot. 0.30 mm.  How to adjust either - the main condition: the valve is fully closed.

[beagle2022]

I adjust them with the engine cold: about 20 degrees C.  .1mm on the inlet side.  .25mm on the exhaust side.

[polymathman]

On my car, the adjusters themselves were worn.

At the end of the rocker arm is a socket which pivots on a ball-stud. This ball-stud screw is the adjuster for the valve lash. It must require a certain amount of force to turn, to hold it in position at adjustment. If it turns too easily, then the engine vibration will allow it to gradually screw itself in and increase valve lash.

Check the manual, it will give the minimum torque for this.

I will look for the job number and specs for this.

[polymathman]

Job 5.2-212.
Remove rocker arm and check torque required to turn valve adjusting screw - it should be 20Nm or greater.

[beagle2022]

Thanks.  I hope to not have to do this for a while!  When I am next in there I will check the torque required.

[oversize]

Just watch out for the clips as they can be easily dislodged while you're adjusting the clearances

[oversize]

BTW I've never seen an adjuster with insufficient torque required to turn.  They're usually too tight and they can open up the spanner causing the hex to be rounded (nasty)

[oversize]

I'd be re-checking those adjustment specs cause the don't seem right to me (I can't remember the figures now).  And yes always adjust them cold