617 Valve adjustment, can't hand crank from PS pump nut
 

1982 300D Turbo sedan. Trying to do a valve adjustment. Have read all applicable posts without seeing solutions.

I am trying to move the engine using the Power steering pump nut and belts. I can't get to the crankshaft bolt because of the fan, etc. I also can't get up underneath. The cam moves some, but before I can get it to the closed position, the engine stops turning. I can't get it to move to the correct point.(http://dieselgiant.com/valveadjustment.htm) says, "Number 1 cyl camshaft lobe pointing straight up, 90 degrees relative to the adjusting pad. To your eye this will look like the lobe is in about the 1 o'clock position."

I have seen some posts that say that taking out the glow plugs will help... That will be my next step. Any other ideas? Thanks.

What does "90 degrees relative to the adjusting pad" mean? 180 degrees, maybe?

I rotate the engine by turning the crankshaft from below. There is enough room to get a socket on the crankshaft bolt if you use a short extension bar. You have to snake the tool in between the fan shroud and pulley. No need to remove it until the job is complete. Just don't forget!!!

Do you have the transmission in neutral?

I had this problem when adjusting my valves too. I just tightened the PS belt a little, per Russell's suggestion (video).

Don't waste time by taking out glow plugs. The transmission has nothing to do with it either.
Is the belt slipping when you try to turn it from the nut? if it is, tighten the belt or bump the starter from the contact point block on the right fender well.

The rocker pad tangent plane is 90 degrees to the symmetrical centerline of the cam lobe. See the image I have captioned "Cam Orientation" at:
http://web.infoave.net/~ontheriver/automobiles/300sdvalves.htm

I favor using the starter with a bump switch to rotate the engine.

-Scott

DON'T use the P/S nut to turn the engine! Besides, if you can turn it that way that means the belt is too tight.

Get a deep 27mm socket and a 1/2" ratchet and turn the engine right or get a starter switch to bump it over.

I've heard this is a bad elsewhere but other than the obvious reason (belt too tight) why?

The main reason is the belt, but it will be hell if you ever have to take off the power steering pulley (for a core exchange for example).

I use a 27 mm deep socket and a 1/2" ratchet handle on the crank bolt, and have never ever had clearance problems. The plastic fan blades do touch the handle, but cranking past the blades anyway doesn't seem to hurt anything. Try not to make it more difficult than it actually is.

I've always used the PS pump bolt. I push down the belt with my left hand to tighten it up and turn the bolt with my right. I don't understand how a person can turn the engine using the cranshaft bolt without a helper to observe the position of the camshaft, or do people use an elaborate system of mirrors?

Use the crank bolt per the FSM.

1/8-1/4 turn at a time and keep checking.

one more for the remote starter switch, per the FSM.

I'll be the first to admit I'm not the expert mechanic that many of you are. But I had just installed a new (German) PS belt and both pulleys were in good shape, so I wasn't trying to compensate for a worn/glazed parts, etc. I made several incremental adjustments, tightening the belt just enough to not slip on the pulley, and no more. I recall checking the belt deflection and feeling satisfied that it was still within spec. Then I proceeded to carefully turn the engine in small increments via the PS pump. I don't see the harm in doing this.

Even if you were to go back and slacken the PS belt slightly once the valve adjusting was done, I'd still find it more convenient to do that than trying to rotate the engine at the crank throughout the whole process. Just my .02, "your mileage may vary".