valve adjustment OM617 engine, rotate engine
 

I'd like to find out from those who have done a valve adjustment on the 617 engine what is the best method of rotating the engine. Apparently, the choices are :
1) use the starter
2) use the power steering pump
3) use the crank (may require removing fan)

I did it once and used the power steering pump, but I've seen recommendations against that because it may cause later problems with removing the nut.

Anyone who has done this, please reply with your method and what your opinion is of it and any other method.

Thanks in advance.

I use the power steering pump. It didn't take enough pressure for me to worry about overtightening the nut.

P/S nut

Thats how I've always done it. overtightening the nut? come on, is it really THAT much of a problem? how many people are resealing their own PS pumps anyways. Besides if its that tight take it to a shop and have them zip it off with an impact.

I use the starter, per the FSM.

I wouldn't recommend anything but using the crank. Using the PS nut may work but there's a chance you could overtighten it and it does put undue stress on the PS belt. You can rotate the crank from below without removing the fan and it's much more controlled than using the starter.

But you can't see the cam while rotating from below.

I also use the p/s pump nut, it doesn't really take that much pressure to turn the engine. Plus, I found out my old belt was in bad shape, it slipped like crazy when I tried to turn the engine, so I replaced/tightened it, and it gripped much better! :D

I used the nut on the power steering pump, however, I also removed my glow plugs (time to check them anyway) and that kept the engine from building up compression and made it much easier to turn. I also grabbed a belt and pulled on it in the direction of rotation at the same time so as not to put all the turn stress on the power steering pump nut!!!!:scholar: Had no problems!

The FSM specifically says NOT to use the PS nut to turn the engine...
it is not that someone might want to reseal the PS unit.... but if you want to replace it you may need that pulley to move to the new one...and it is a TAPER shaft...so overtightening it has nothing to do with the nut... but everything to do with the pully and the PS shaft.
There is a ZEN about some things... perhaps this is one where you could go with the idea that not all mechanicing jobs are ONE PERSON deals....
pulling the glow plugs , and then having someone underneath with a proper ratchet works very well .

I'm relatively new to these things, and I found it pretty easy to remove the fan and shroud on my 240D and then rotate the engine from above using the crank. Just don't forget to put one of the fan's bolts back in once the fan is off so that the holes stay aligned during the cranking. I didn't and then had to loosen the alternator belt in order to get the holes aligned again and the fan back on. Still, I'd say it added less than 10% time/effort to my very first valve adjustment job and felt worth it to do the job "right."

Ditto: 27mm Deep & 1/2" ratchet on the crank bolt.............Per the FSM.
Also, the easy thing to do is count your strokes (3 is a good number IIRC) and you should have another cam lobe in position to measure. Less up and down exercise that way.

One wrench on the PS pump (just don't jerk the wrench, use nice even pressure) and one hand on the crankshaft pulley to help it turn (you can jerk this one with your hand to get things moving). This puts very lttile pressure on the PS pump (or maybe my compression sucks).
Also, if you adjust each valve as it comes up (rather than starting at the front of the engine and moving towards the back), you don't have to rotate the camshaft much at all. (Just make sure you write down the one's you have done so you don't get confused).

P/S nut, then your in position to check your chain stretch, unless you want to haul out the dial indicator and make a big deal outa that too:D I realize if your doing it for pay that might be another thing.