I removed the vacuum pump, which was replaced about 5,000 miles ago. I noticed the timer cam was not perfectly smooth. See photos. Should I replace this? The wheel on the vac pump still lookks ok. I was thinking of using some fine emery cloth and cutting oil and trying to polish the timing device cam.

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GSXR's pictures (For your comparison Purposes)
I'm sure you've seen his post on (Almost)Catastrophic VP failure?
OM603: Vacuum pump explosion, bearing intact! Injection Pump Timing device wrecked

I'm already scared to death of my VP Cam interface.

Pierburg and Mercedes would probably say replace.

opinions much more expert to follow ,shortly.

(It sure looks like something other than the VP roller has been interfacing with
the Cam? Did you encounter any "Stressful" actions removing the VP that would account for the Imperfections on the Cam?)

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Virgin (As In still in box)
For your comparison:
('Wish I knew WT* I was doing Photographically,Shot these through a Magnifying Glass using ZOOM)

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(Once again forgive the photography)

Timing Device with 10K wear on it.

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I don't think any wear or gouges occured when I removed the vac pump for inspection. My previous vac pump failed and disintegrated. I suspect any wear to the timer cam occured before I removed the new one. Since the timing device cam "rolls" the roller instead of scraping it like a camshaft lobe/lifter relationship, I believe I can "polish" the timer cam enough to drastically reduce wear on the roller. It appears to have a sort of "scalloped" wear pattern on the surface of the timing device cam. Even the photos of a brand new timing device appear not to have a very smooth surface, as compared to other machined surfaces on an engine. Emery cloth will do a surprisingly good job of smoothing a metal surface, with patience.

Are you going to "Polish" it in place?
I'd be tempted to expose the process to a very strong shop vac to reduce the
probability of any swarf falling down into the TC cavity.
(rags stuffed into the cavity under the Timing Device ,first of course.

In Hindsight, after looking at the old pictures I took of the slightly used TD
mayhaps yours doesn't look so bad...

I'll see what I can do to make the 186,000 mile Timing Device visible sometime
this weekend.'should give a better comparison.

In comparison your Roller has a definite Burnished (Polished) appearance VS
the "New" roller

I am coming to believe the "Ramps" on the TD have less Brinell (Hardness rating) than the Roller on the VP.

[I 'll tell you what,I'm going straight to 15W40 Synthetic after seeing these.]

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Not to hijack ,but whats a good 606 head worth ?I see these once in a while at the yard and would spend some extra time exploring a pull if their a rarity.

Here:

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Is the bolt that secures the timing device "reverse" threaded?

Also--someone on these forums suggested (from experience) to use a credit card between the timing chain and timing device teeth to remove the device. Something about manually rotating the crank whilst inserting the credit card between the chain and teeth as it rotates.
Feasibility anyone?

And how do you maintain camshaft timing in such a procedure?

Is it difficult to remove the timing device from the injector pump shaft once the bolt is removed? And to install?

If only Haynes made a manual...

YES, the bolt that secures the TD is Reverse Threaded. (As in Lefty Tighty,
Righty Loosy)

A Flywheel locking device,Once you've set the crank...AND Zip (or Wire Ties)
securing the chain to the Camshaft Sprocket will maintain basic Timing.The
Injection Pump is secured by the Locking Device.['Must remember to R+R
the Chain Tensioner.]'Must remember to remove the locking device from the
IP ,OR 'orrible things result.

These (For what little the Gnomes divulge) are the TD R+R instructions for
the OM606:
http://www.ps2cho.net/downloads/MB%20CD/W124/w124CD1/Program/Engine/605_606/07.1-8014.pdf

GSXR suggests using the OM603 directions for TD removal since the OM606
directions are so sparse.
http://www.ps2cho.net/downloads/MB%20CD/W124/w124CD1/Program/Engine/602_603/07.1-8014.pdf
You'll note the directions suggest using metal strips to isolate the chain for TD removal.
(Some of GSXR's pictures,you might ask him how he secured the Chain @ the TD)
Picture of IP locking device.

Vacuum Pump Implosion Thread:
OM603: Vacuum pump explosion, bearing intact! Injection Pump Timing device wrecked

The COMPLETE lifetime masochist's guide to the OM606:
(In an easy study guide format...less time searching,more time for Angst
with the Mercedes in the Garage.)
http://www.ps2cho.net/downloads/MB%20CD/W124/Index/605_606index.html

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These are the pictures of the TD ramps from the deceased OM602.The Vacuum Pump(as you see, is the dreaded Open Bearing model) is stamped 0045 which means it's a year 2000 model [at least 100K according to engine records.]
The Vacuum Pump roller shows little Burnishing on the Driver's side so I suspect "Zomezing" funny may have been going on there.
The TD Ramps show the same wear pattern.

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