Old Sergio runs Crappy after a valve adjustment

[Antique benz lover]

Hi,

I have an 84 300d and following a valve adjustment to clear the smoking and hard starting issues it runs worse. Yet it now starts easier and no smoke. just a fast Idle and she seems to lope almost sounds like its missing. Seems to run good at highway speeds though. Someone says timing chain or IP adjustment ??? The car has over 250k

I have an 82 300sd and following the valve adjustment it runs fine! So the procedure is not new to me any help would be appreciated

Thanks

Frank

[Ozarkdude]

You didnt say how loose or tight of valve clearance you had before hand. Have you done a compression test? You can also crack an injection line and note rpm drop cyclinder to cylinder.

If the chain is stretched valve timing would be retarded [late], excessive clearance would give later opening, earlier closing of valves.

Its so hard to determine just what would change and its effect, but as you noted a negative effect its should certainly be investigated. Its rather easy to check cam timing, a bit more involved to check injection timing, but your going to need to do it to start the diagnosis.

My first question though is if you goofed up an adjustment and got one too tight. I would go back through them all one more time, and double check not only the physical clearance but that your rock positive your using the correct feelers or made the correct conversion from metric to inches, and they easy slip in and out. Should be .008"/.010" intake/exhaust IIRC (but dont quote me)

[Antique benz lover]

This is driving me crazy. I went in TWICE to adjust the valves set them at 004. EX 0013 intake. She still runs lousy. I'm going to limp her into an old diesel mechanic. Hope you have a good CHristmas and thanks for your time