Valve Adjustment Question - PeachParts Mercedes-Benz Forum

300DFarmer · #1 06-06-2007, 08:14 AM

Hello,
I am in the process trying to adjust the valves on my 82 300D Turbo. I tightened the PS belt before I started, but I cannot get the engine to turn by using the PS bolt. It turned a little then stopped. I don't want to break anything, so I'm looking for some quick advice to help me finish the job.
I just flew down to South Carolina from Vermont to buy this car and would like to finish this job, so that we can head North.
Thanks

Douglas.Sherida · #2 06-06-2007, 08:58 AM

There are alot of way to rotate the engine and I'm sure you'll get severla suggestions. I prefer to do it by hand to eliminate any possibility of it starting up.

When the PS belt slips (as mine does), I reach down with my left hand and rotate the crank balancer pully (the other end of the PS belt) while rotating the PS pump with a wrench in my right hand.

It requires some effort but is simple to do and you won't break anything.

Gurkha · #3 06-06-2007, 09:05 AM

I jack up one of the rear wheels and put the car in 2nd gear, of course this is only possible with manual tranny, I have another person turn the wheel, this is the safest way of turning the cam.

toomany MBZ · #4 06-06-2007, 09:35 AM

I have a device that I use, a plastic pistol grip affair with a trigger that alligator clips onto two of the three screws attached to a "buss" on passenger fender. Available at any AP store. A little black box that is hinged, open it, you'll see. Trace from battery. All you have to do is connect #1 and #3, the starter will engage. You are bumping just enough to turn cam, no GP's, won't start. I also use this when replacing belts, get 'em almost on, don't use your fingers, bump the engine, "walks" on.

Stevo · #5 06-06-2007, 10:53 AM

Just put tension on the belt with your other hand, bare down on it till its past a compression stroke.

rhodes2010 · #6 06-06-2007, 11:00 AM

And... my favorite way.

Put a socket on the crank pulley, maybe 3 inch extension.
Turn crankshaft by hand.

I think it is a 26 or 27 mm or maybe 1 1/16 inch.

635CSi · #7 06-06-2007, 11:07 AM

Quote:

Originally Posted by rhodes2010

And... my favorite way.

Put a socket on the crank pulley, maybe 3 inch extension.
Turn crankshaft by hand.

I think it is a 26 or 27 mm or maybe 1 1/16 inch.

Its a 27mm, I use the same method!

Motorhead · #8 06-06-2007, 11:42 AM

Quote:

Originally Posted by Stevo

Just put tension on the belt with your other hand, bare down on it till its past a compression stroke.

Thats the way I do it also. NEVER had a MBZ diesel engine that I couldn't turn that way. Make sure that you turn the engine clockwise ONLY. Turning it the other way collapses the cam chain tensioner.

SD Blue · #9 06-06-2007, 12:43 PM

I use a 1/2" dr. ratchet & 27mm deep socket on the crank pulley bolt (per FSM).

To eliminate a lot of the up-n-down, I count 4 strokes of the ratchet, which results in another cam lobe being in position to measure. This also gives your back a break from leaning over the engine for an extended period.

firemediceric · #10 06-06-2007, 02:56 PM

Quote:

Originally Posted by rhodes2010

And... my favorite way.

Put a socket on the crank pulley, maybe 3 inch extension.
Turn crankshaft by hand.

That's how I do it, also. The transmission is in neutral, isn't it?

lemur · #11 06-07-2007, 12:01 AM

Quote:

Originally Posted by toomany MBZ

I have a device that I use, a plastic pistol grip affair with a trigger that alligator clips onto two of the three screws attached to a "buss" on passenger fender. Available at any AP store. A little black box that is hinged, open it, you'll see. Trace from battery. All you have to do is connect #1 and #3, the starter will engage. You are bumping just enough to turn cam, no GP's, won't start. I also use this when replacing belts, get 'em almost on, don't use your fingers, bump the engine, "walks" on.

I used the above technique (thanks, toomany

), but I did not use a special tool. I just touched the two points from a set of needle-nosed pliers to the two screws to bump the engine. Be careful, though--make sure you're ready to use the pieces of throttle linkage that you haven't removed to shut the engine down if it starts. Somehow, my engine did start once doing this, even though I was bypassing the glow plugs (don't ask me how

).

Of course, if you find the thread I started about my first valve job, you would probably decide not to do anything I advised

.

vstech · #12 06-07-2007, 09:08 AM

anytime I am working with turning over the motor, I usually wire the stop lever linkage in the full closed position. simple preventive maintenance. I would use the starter to turn the motor. the crank bolt seems too difficult to get to easily and the PS belt method can cause problems down the road.

toomany MBZ · #13 06-07-2007, 04:41 PM

Quote:

Originally Posted by lemur

I used the above technique (thanks, toomany

), but I did not use a special tool. I just touched the two points from a set of needle-nosed pliers to the two screws to bump the engine. Be careful, though--make sure you're ready to use the pieces of throttle linkage that you haven't removed to shut the engine down if it starts. Somehow, my engine did start once doing this, even though I was bypassing the glow plugs (don't ask me how

).

Of course, if you find the thread I started about my first valve job, you would probably decide not to do anything I advised

.

Sounds like you have a strong engine.

300DFarmer · #14 06-10-2007, 10:23 AM

Thanks all for the advice.
Sorry to not reply earlier, but couldn't get back online in NC. Thankfully, I'm back in Vermont --it hell out there.
My advice from this learning experience is to not try to adjust the valves after a sleepless night of travel.
The car was not in neutral. I figured this out shortly after my post.
Just goes to show that you can make a foolish mistake even if you have done something before. Needless to say I checked the clearances three times before putting the valve cover back on.