I really messed up now - adjustment snafu - PeachParts Mercedes-Benz Forum

matthewdear · #1 07-14-2011, 10:27 PM

Just bought my MB, a '80 240d. Guy owned five MBs and had never had or did a valve adjustment. All had 200k miles plus on them. So, after buying the car I did a lot of research and when prepping for the adjustment I had notes, a diagram so I wouldn't forget what valve I was doing, my netbook with two pages on adjustments, and all the tools (even the special bent wrenches.) So: I mistakenly thought the starter was the power steering pump and turned that nut to turn the engine. It actually worked for about 3/4 a turn. Then the belt kept slipping (that's what I hope happened.) Then I went back to my Haynes and other resources and tried the nut at the front of the camshaft. Wouldn't budge. Then I tried the powersteering nut, which I didn't want to do, as I've seen the warnings posted here and on other sites. I tried the nut that is between the radiater and the engine (camshaft pulley?). Wouldn't budge. So, I did the trick of jacking the car up in the rear, putting it in fourth (a manual trans), and the tire wouldn't budge. E-brake is off, btw, with bricks around all the tires. What am I missing? I replaced the gasket, but wanted to do the adjustment, as I can hear that the engine needs it (and the history of the car/and owner would suggest it's worthwhile). Also: after putting it all back together after not even getting to start the adjustment, when I started the car it now makes quite a racket: knocking as if there is no oil, like in a gasoline car. I am trying not to panic, I did take it for a drive after and it runs as it did before, just loads of knocking. Please, some words of advice! I have searched for my situation on this site and others, as well as google-ing it but may be describing it wrong: I know how you all get frustrated with folks who just ask without even looking into it. Thanks in advance. The ?s are how to turn the engine. And what could knocking be after just taking of the valve cover. and also: can I do the adjustment and not have to replace the gasket again, I mean, does taking off the over make the gasket get out of shape, hence requiring a fresh one to seat again properly?

vstech · #2 07-14-2011, 10:40 PM

#1, WELCOME to the forum!
This is the BEST place for MB Diesel help. ZERO exceptions.

first off, on a car that's never had a valve adjustment, it's certainly going to need a new gasket! IF you mean the new gasket from your recent adjustment, then no problem, it'll be fine. be sure and clean it off, inside and out, and the surface of the valve cover and the head.
I'm concerned you could not turn the motor with the crankshaft bolt. try again with the car in neutral, and see if it will turn.
if you have adjusted one too tight, the valve could be banging. or if it's too loose it could as well.
plenty of spots to download a pdf of the valve adjust diagram, www.dieselgiant.com has a nice one in the mercedes maintenance page.
did you by chance turn the motor backwards? some models of the timing chain adjuster are ratcheting, and if you turn it backwards, the slack would get pushed on by the tensioner, and could be binding...
I'd pull the valve cover off again, and look over the banana bars...

matthewdear · #3 07-15-2011, 12:14 AM

I did change the gasket for a new one, so I will make sure I clean it off and reseat it when I adjust the valves this weekend (if I can get the engine to turn.) Initally, when I tried to turn the alternator (in front, to the left, lower) nut I may have turned it counterclockwise a degree, maybe. At that point I went to the notes and started turning it clockwise. It did make the cam turn, I only could get it to bring the lobe around a quater revolution (exhaust #1), at which point I think the belt slipped and I just ended up turning an turning without the engine turning. Then I tried turning it by the above mentioned methods. I also grabbed the sproket and tried turning that by hand, which of course didn't do a thing. I didn't try the powersteering nut, I now remember (off of advice read elsewhere.) And I'm stymied why turning the wheel didn't turn the motor, coudn't even budge it. Do I need to have the other wheel of the ground as well? I was so proud of myself for getting thus far, and hope I didn't mess things up somehow. I am not unfamilar with cars, have changed brakes, alternators, sparkplugs, etc. in my other vehicles, so I must be missing something with this new type of car (to me). Thanks again in advance. It did drive around as before, just knocking now. Could turning the engine backwords, if I did, just a degree (as I could only get my hand in there so much) binded the timing chain? And how could I tell if I did?

babyjames · #4 07-15-2011, 12:18 AM

You mean the alternator, I'm guessing? Did you rotate the engine clockwise, or counterclockwise?

Jay.

babyjames · #5 07-15-2011, 12:22 AM

All right, you beat me to it. You'll want to pull the valvecover back off and check the timing marks. Set the crank pulley to TDC and then look for the marks on the cam sprocket and cam bearing tower.

Jay

kerry · #6 07-15-2011, 12:32 AM

Not sure what is going on, but the knocking sound is bad. Don't drive it or start it until the problem is resolved. One test you might perform to determine if the problem is serious--ie metal to metal somewhere, is to remove the glowplugs so the engine has no compression. Then with the transmission in neutral (and wheels blocked) try turning the engine using the big bolt at the crankshaft. If you can't turn it with a socket and breaker bar with the glow plugs removed, there is definitely something seriously out of whack.

By the way, I don't think anyone would be able to tell if a MB 616 or 617 diesel needed a valve adjustment from listening to the engine. So whatever you were listening to that lead you to that conclusion wasn't maladjusted valves, unless for some odd reason they were loose and not tight from not being adjusted in a long time.

Another, by the way

While I've never tried it, I seriously doubt that a person could turn over a 616 by hand using the rear wheel in 4th gear. Maybe with a lug wrench but not by just trying to turn the tire by hand.

babyjames · #7 07-15-2011, 12:34 AM

Sure you can. If the valves are too tight on a n/a engine you can hear it "coughing" back through the intake/air cleaner. Not so on a turbo. At least not from my experience.

Jay.

layback40 · #8 07-15-2011, 01:25 AM

Quote:

Originally Posted by babyjames

Sure you can. If the valves are too tight on a n/a engine you can hear it "coughing" back through the intake/air cleaner. Not so on a turbo. At least not from my experience.

Jay.

You are right about the coughing on a N/A Jay !! Take the lid off the air cleaner & it puffs like a steam train. The inlet valves need to be way out of adjustment though & the motor cold.

Stretch · #9 07-15-2011, 01:03 AM

First thing I'd recommend is that you only ever turn the engine over with either

1) the starter motor (electrically => turn the ignition key or use a clip on starter switch)

2) with a 27mm socket on the crankshaft pulley.

If you are turning the engine with the 27mm socket on the crankshaft pulley turn the engine over in a clockwise direction (viewed as you are looking at the front of the engine). DO NOT TURN IT the other way.

kerry · #10 07-15-2011, 01:07 AM

Kinda off topic, but does anyone else find it odd that right/left on a car is determined from the point of sitting in the driver's seat but clockwise/anticlockwise on the engine is determined from standing at the front of the car looking at the engine?

Stretch · #11 07-15-2011, 01:13 AM

Quote:

Originally Posted by kerry

Kinda off topic, but does anyone else find it odd that right/left on a car is determined from the point of sitting in the driver's seat but clockwise/anticlockwise on the engine is determined from standing at the front of the car looking at the engine?

Yes it is a daft convention - everything should be with reference to the item's position to Mecca...

layback40 · #12 07-15-2011, 01:22 AM

Quote:

Originally Posted by Army

Yes it is a daft convention - everything should be with reference to the item's position to Mecca...

& make sure you do the opposite to what ever I say as I am in the Southern hemisphere !!
The steering wheel is on the right side of the car & you drive on the left side of the road.

Stretch · #13 07-15-2011, 01:24 AM

Quote:

Originally Posted by layback40

& make sure you do the opposite to what ever I say as I am in the Southern hemisphere !!
The steering wheel is on the right side of the car & you drive on the left side of the road.

Yeah I forgot about the Coriolis effect.

tangofox007 · #14 07-15-2011, 10:14 PM

Quote:

Originally Posted by kerry

Kinda off topic, but does anyone else find it odd that right/left on a car is determined from the point of sitting in the driver's seat but clockwise/anticlockwise on the engine is determined from standing at the front of the car looking at the engine?

That is not the SAE convention. The SAE defines engine rotation from the perspective of viewing (facing) the flywheel. That makes the OM617 a CCW engine.

-=DeanstuD=- · #15 07-15-2011, 03:42 AM

I don't have the answer, but welcome. Send pictures, and where are you from? Maybe someone nearby could take a look...