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Old 07-25-2002, 12:09 AM
Posts: n/a
Question M117.963 Valve Lash Adjustment

Hi all,
I'm new to the forum, but is looks really good. Hope someone can help me. There sure is a lot of experience out there.

I am trying to resolve excessive valvetrain noise on the LH head of my 1985 Euro W126 500SE while doing valve seals, timing chain and oiler tubes. Engine teardown revealed moderate wear on some of the hydraulic compensator ball studs and associated rockers plus wear noted on the trust pieces on top of the valves. Cam lobes and rocker thrust faces look fine (at 248.000 km).

Having read up on the M116/117 valve setup (although I have no manuals/CD Rom), it conceivable to me that the collective wear may cause the ball studs to "bottom out" (max extension), leaving excessive valve lash and subsequent clatter noise.

Various write-ups discuss the need to adjust the clearance by installing thrust pieces of different thicknesses under the rocker. They also talk about a special "initial set-up gage" required to accomplish this task. I guess this is normally all sorted out at production and the hydraulic compensator elements look after any in-service wear.

Now that I have the thing in pieces on the bench, I'd like to set up the clearances properly so that the compensators work within their design range once again. Is there anyone out there who has done this, or who can describe the procedure for setting up the thrust pieces/clearances? I'm not usually phased by "special tool" requirements, as a bit of innovation can do wonders...

Any assistance or clarification will be greatly appreciated.

Kind regards,
Willem Moolenaar,
New Zealand
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