Folks:

This afternoon my hands got ahead of my sense and I turned the PS pump between 1/5 and 1/8 of a turn CCW. I was trying to rotate the engine in order to bleed air out of the fuel injector hard lines. The engine produced an unexpected clank (not too loud, though) when I began to rotate the engine CW.

The engine is an OM616.912; original installation in a 1978 240D with 561K.

My questions: What, other than changing IP timing, might I have done by turning the engine CCW? In the case that I have messed up the timing so much that the engine will not start, is it still possible to repair the timing without removing the IP from the engine? Am I correct in assessing that the IP in this car (123.123) is an MW model? How can I tell?

Any advice is greatly appreciated.

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'Betsy the Getaway Car' : 1978 MB 240D, 582k
'The Mistress of the Sea' : 2001 Giant Boulder, 10.30k

Technically speaking, your crankshaft normally rotates in the CCW direction. Unless, of course, you engage in the assinine ritual of reversing what is "normal" because you like to face south while you car points north.

Indeed, but what about if my car is facing west?

Seriously: From what I've read elsewhere on the forum, the direction of the output to the driveshaft is CCW, but I was speaking of the direction in which I turned the PS pump. What can I expect to happen since I rotated the engine CCW from the front?

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'Betsy the Getaway Car' : 1978 MB 240D, 582k
'The Mistress of the Sea' : 2001 Giant Boulder, 10.30k

Rotation is CW forward facing aft.

When forward facing aft, the direction of the vehicle clock also changes, thereby redefining "clockwise." Since the clock is, by definitiion, unable to rotate counterclockwise, its formerly CW direction is reversed and becomes the new CW direction, which leaves the crankshaft rotating CCW.

No matter where you stand, the clock and the engine are turning in opposite directions. No two ways about it.

you may have skipped a tooth on the crank.

you may have struck a valve with a piston

yes

you identify an engine's rotation by looking directly at it's pulleys. These engines rotate clockwise (CW), Hondas rotate counter-clockwise (CCW)

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Because there seems to be confusion, I mean to say that I rotated the PS pump 1/5 to 1/8 of a rotation CCW: with a 21mm wrench applied from the top of the pump, I moved to the left.

jt20, thanks for some details on this. What are the consequences of skipping a tooth on the crank? How can I tell if I have struck a valve with a piston, and how can I fix this?

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'Betsy the Getaway Car' : 1978 MB 240D, 582k
'The Mistress of the Sea' : 2001 Giant Boulder, 10.30k

That's a factually incorrect statement.

If you're standing forward and facing aft, the engine rotates clockwise.

Period.

Doesn't matter where you stand. The clock and the crank rotate in opposite directions.

Another factually incorrect statement.

The clock rotates clockwise..........the engine rotates clockwise..........forward facing aft.

The convention applies to automobile engines and jet engines..........you're clearly confused about it.

I meant to say "you MAY have struck a valve"

turning the P/S pump CCW causes the crank to turn CCW

A leak-down test will tell you if you broke the valve, but I'm not certain how you'd tell if there was an impact without a boroscope or removing the head.

if the crank has skipped, it can easily be determined by checking your chain stretch (search - there is plenty of info).

the consequence of skipping a tooth is that is must be fixed before you run the engine.

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Not according to the SAE. Plus, looking at the pulleys might get a bit confusing when a serpentine belt is involved; sometimes the crank pulley and water pump pulley turn in opposite directions, for example.

What convention? An obsolete one?

The convention that describes the rotation of an engine. You stand at the front or the rear of the engine and look "forward" or "aft". Your position is along the axis of the engine. The engine rotates either clockwise or counterclockwise. You qualify your answer by stating your position:

example: A CF6-80 rotates CW, aft looking forward.

example: A 617 rotates CW, forward looking aft.

You may be confused with the changing of the clock if you walk from the front to the rear of the engine.........but the addendum to the statement qualifies your answer.

I see your point. Conventions like this do matter. (For instance, aerospace engineers consider force to be positive in the "down" direction, pretty much in opposition to the rest of humanity; if one engineer decided not to abide by this convention in consulting with his colleagues, I cannot imagine his project getting very far.) However, from what I've observed over the past couple of years, the (I thought) commonly-understood convention among the users at this board is tied more to the movement of parts at the front of the engine.

But all of this argumentation seems pointless. Let me put it another way. I know which way I should have turned the engine, and I turned it 1/5 to 1/8 of a rotation in the wrong direction. What should I investigate?

__________________
'Betsy the Getaway Car' : 1978 MB 240D, 582k
'The Mistress of the Sea' : 2001 Giant Boulder, 10.30k