Valve adjustment-finally tackled it! - PeachParts Mercedes-Benz Forum

showme · #1 11-20-2010, 09:03 PM

I finally adjusted the valves on the wife's 81 300D today, and it was a breeze. Figured this 60* weekend would be my last this year, here in Missouri anyway, so I got out the Hazet's I bought last spring and got out the Haynes manual and tore into it. Piece of cake. Can't believe I put if off this long. All of them were tight, EXCEPT for the back one by the firewall!

I went back and rechecked them, and for some reason it seemed the exhaust valve's all were ok, but I had to loosen almost all the intakes.(?) While I was at it, I changed out all the injector fuel lines since I had them already, and one or two were leaking a little bit. Greased up the linkage, and it seems to be humming along fine. Since this is the first time I've done this, I've got two questions. 1) Just how tight are you supposed to tighten the lock nut after you have the clearance set? I snugged them down pretty good, but I was afraid to go too tight for fear of messing something up. 2) My K-D feeler gauges were off a tad from spec. I'm not worried about the .10mm, which is .102 in my set, but the book called for .30 (cold), and my gauge is .330. Is this a problem?
Anyway, thanks for all the previous posts on here from everybody, whunter in particular, along with weird beard for the push in the last few days. Anybody who's been putting this job off, don't. It's one of the easiest things I've done on this car! The tip on using the power steering bolt to turn the shaft made the whole thing easy. My 12" Crescent did just fine when I couldn't get my ratchet and socket in there. Thanks everybody!

layback40 · #2 11-20-2010, 09:20 PM

Great to hear of your success !!
Its better that they are on the loose side of the spec. They close up in time. I ran for a couple of thousand miles when I first got my 84 having only set them by guess without feeler gauges.
Its not a hard job, its technically harder than many though.
I am sure there is a spec for those lock nuts, just remember you will need to undo them next time so no super tightening !! At the same time its a PITA if they come loose. I hope you get the general idea.

Good luck with your car.

vstech · #3 11-20-2010, 09:29 PM

good job! yeah, .03 loose is not going to be noticed. odd that your intakes were all tight, and the exhausts were not but it's a smaller measurement, perhaps tightening the nuts threw you off a hair. no worries.
since they were all tight, be sure and go back in 500 miles and check them again. they will all need readjustment.

Renntag · #4 11-20-2010, 09:46 PM

Congrats. Thanks for the reminder. before I start pounding miles out on the W123, I need to do a valve adjustment.

Its gratifying when you get stuff like this done!

showme · #5 11-21-2010, 07:07 AM

Thanks for the kind words, folks! It's nice to have a job go so smooth after busting my knuckles on so many. Though I've been a welder for 30 years and an Ironworker for over 22, a mechanic is something I've always done out of necessity, or rather the idea that I'm not paying all that money for something I can do myself!" from my younger (poorer) days. I do it because it needs done, and it gives me a good feeling when a job is finished. And, thanks vstech for the 500 mile adjustment heads up. That's one thing I had not heard before. Also, I don't know if I stated it clearly, but all the valves were tight (except the back one, which was good already), but when I went back around for the second "check", the intakes were tight the second time around, it seemed. (Except the back one). Thanks, again, everybody. I think I'll change my engine mounts today!

4thesporty · #6 11-21-2010, 11:29 AM

Torque specs:

4thesporty · #7 11-21-2010, 11:34 AM

Cap nut torque:

~15-22 ft/lbs

showme · #8 11-21-2010, 12:19 PM

Thanks, Adam. My Haynes manual said .30mm. It figures spec would be .35.

As far as the torque, it's too late for this trip, but I'll use that at my "500 mile adjustment". I see another reason why it took me a while. I'm used to the top nut being the lock nut. I was setting the lower one, then tightening the cap nut. (DOH!) Oh well, when it was all done, it was right. Live and learn, right? Thanks again.