Hey, just got finished freshening up the internals on my 74 240d motor. I have the cam timing and crank timing set, and now need to reinstall the injection pump.

From my understanding the procedure goes as follows:

Turn motor to 24* BTDC (cyl 1)
align "marks" on the IP splined shaft and the IP body.
install IP
set exact pump timing using the drip/rotate method.

Here's where I have a question:

The pump "marks" will not stay in position. The pump turns back a few splines as soon as I let go of the splined shaft. I imagine this is due to the spring plate/cam plate/whatever the internal parts are called on the pump wanting to return to the "non-pumping" state. Seems to be the same kinda deal between other brand injection pumps I've installed before, so no real surprise there.

Anyhow, HOW do I keep the mark aligned? Or do I get them as close together as possible before the "return" motion happens and install like that? Or perhaps turn the motor back further to compensate for this?

Any thoughts or info would be much appreciated. Thanks!

I pretty much copied exactly what was said in the Manual. I would read the very last pargaraph "note" first as that explains why you are setting the crank at a different degree setting.
The driver is the splined gear on the Fuel Injectin Pump shaft.

From Mercedes Service Manual Engines OM615-617

Set crankshaft to the following values in compression stroke of first cylinder.
615.913 47 Degrees before TDC
615.912 45 degrees before TDC
616 45 Degrees before TDC.

Set injection pump to begin of delivery. For this purpose, keep turning the pump shaft until tooth gap on the driver and the marking on the injection pump are in alignment.
When applying slight pressure on the driver towards the left (opposite to the direction of rotation) the driver will jump back 2 teeth to basic cam circle under the influence of the pressure-loaded camshaft of the camshaft.The 2nd tooth should now be in alignment with the mark on the injection pump housing. Prior to installing the injection pump. Check ounce again whether crankshaft is at 47 degrees before compression TDC of engines 615.913. Or 45 degrees of 615.912 and 616.)

Note: The adjustment of the crankshaft to 47 degrees or 45 degrees before compression TDC is required because the driver has been taken back 2 Teeth.

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84 300D, 82 Volvo 244Gl Diesel

Awesome, that is exactly what I was looking for. I must have missed that part in the service manual, I'll have to look it over again and see if its in there and I went temporarily blind.

Thank you very much!

I counted the teeth at 70 or 5.14 degrees each so shouldn't 2 teeth just add 10 degrees making it 34 for 615.912.
Also I have the 114/115 service manual and see no reference to that.
I have set crankshaft to 24 then checked delivery and it was at 0. Then I set at 45 per this post and now delivery at 40

For others here is a site that has the Manual the 240D part of the site works: Mercedes-Benz Model 114/115

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84 300D, 82 Volvo 244Gl Diesel

You rotate the Engine in the direction of normal rotation and as you are coming up on the compression stroke before top dead center you stop at 24 degrees before top dead center.

If you are using the drip method and are not getting the right amount of drips you need to loosen the Blots/Nuts holding the Fuel Injection Pump to the block and rotate it a tiny amount. I don't have a 240D but on my rotating the top of the pump towards the Engine (do that with the fuel injection hard lines loose at the injectors) advances the timing and rotating the fuel injection pump towards the fender well retards the timing.

What I do is rotate a tiny amount and tighten one nut and start pumping on the hand primer and watch the drips. You need to pump it to keep the pressure even less presser equals less drips. If you pump enough the Fuel Pressure relief/overflow valve will level off the pressure.

When you get your number of drips tighten all of the fuel injection pump flange nuts.

Note that just sticking the Pump in at 24 degrees before top dead center generally only approximates the timing.

On the OM 617,952s one of the ways you know you are on the compression stroke is to look down into the oil fill cap hole and see the two #1 make kind of a "V" shape with the lobes upwards.

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84 300D, 82 Volvo 244Gl Diesel

The IP shaft rotates x2 slower than the crankshaft.
The collar has 68 splines= about 5.3°. Two will give you 10.6° which will read roughly 21° on the crankshaft. Add 21° to 24° =45° installation point read on the crank with the pump shaft set 2 teeth back (to alleviate the lobe pressure on the first element follower).
Same technique applies for 2-liter om615's (.913;.940) and om621 (crank must be set at 47° BTDC,compr.stroke as they require feed begin @ 26° BTDC).

Thank you. I was not aware of the 2:1 ratio of ip to crank

I started out rebuilding the 615.912 for my sister with zero knowledge of diesel at all. though I've only posted this once, I'd like to thank members like Vox, Diesel, WHunter, Barry, etc... for all your knowledge and the willingness to share it. Without you guys I'd probably still be staring at av pile of parts. Having multiple install attempts at the IP I've learned that I need to try to make IP final position as close to engine as possible. If rotated away from engine it becomes near impossible to access bottom bolt as my oil filter housing is prior to the upgrade with recess on top to ease access