Recent personal experience here. I adjusted the valves on my '84 300TD a few weeks ago and didn't have too much trouble. This was the first time I had adjusted the valves on anything by myself. Car ran okay beforehand, but had quite a bit of clatter at idle, some shake, and the valve noise was a bit more pronounced at high rpm - very clear at 80mph. After the valve adjustment, the car was much smoother and quieter. I did notice a bit more low end torque, also.

I bought an OEM set of valve wrenches, including the third one for holding the valve still while adjusting, and they made the job very simple.

Concerning what you said about holding the top nut while tightening the bottom nut: I tried it like this to begin with, but found that this method didn't work very well; like you said, the clearance would be correct, then you tighten the bottom nut, then the clearance would be tight.

What I did was tighten both nuts at the same time (the bottom wrench tightening at a quicker pace than the top nut) while simultaneously sliding my feeler gauge between the cam and the rocker arm. It sounds weird but you kind of get a feel for it. Using this technique allowed me to tighten down the nuts at the exact moment the clearance was perfect.

In addition, I did the job without having to remove anything besides undoing some throttle linkage pieces and obviously, the valve cover.

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1984 300TD Turbodiesel - 272k
- Daily Duty
1985 300D Turbodiesel - 315k
- "Recommended for competition events only"