I am at the tail end of a head rebuild. Cams and timing chain gear are installed and in the same position as when I removed them.
While installing the timing chain gear and on the last of three bolts the whole system moved while tightening the last bolt. Both camshafts and the timing chain moved in unison (rotated) but I cannot see down where the timing chain attaches to the crankshaft so I am not 100% positve about the timing chain jumping a tooth on the crankshaft.

Will someone tell me how to put the engine at TDC and the cams? I haven't looked yet but I guess there is a mark on the harmonic balancer or pulley.

Fair winds and following seas, friz

the balancer should be marked 20degrees before and after OT which would be TDC

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1987 300TD
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And there is a hole in the cam gear that lines up with a hole in a cam tower support so you can find TDC on the top side as well.

Like so:

PeachPartsWiki: Timing Chain Check

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both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

I have been on travel for a couple of weeks so the cylinder head rebuild project has been on hold. Thanks for the help. Cams are in with bolt installed and drift marks on the cams lined up. When trying to rotate the crank in either direction it only moves about 10 degrees before stopping. The engine is about 180 degres out from "OT" as the OT and degree marks on the balancer are at the bottom. The timing chain gear is not installed. I am holding up the timing chain when rotating the crank. There is a chain tensioner/spring of some sort down by the crank which I can't see. If I pull hard on the chain it gives up about 2 inches of slack.
So, any ideas why the crank stops? Does it matter if the cams are installed or not? Should I be taking the slack out of the timing chain as I rotate the crank? The chain does move when the crank rotates. Any help is greatly appreciated.
Thanks again, Friz

There is one or more valves in the way of the piston.

You need to remove the cams, get the crank at tdc and then install the cams IIRC. I would have to look in the manual to see what the exact procedure is for cam installation.

You got the timing chain tensioner removed correct?

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Jim

Thanks shipmate! That makes sense. Yes, the timing chain tensioner on the passenger side has been removed. Don't have a manual but I have a printed procedure AR.20-P-6992HA Remove/install camshafts. A little vague so I filled in the details with a procedure which appears to work. First installed the cam on the driver's side (intake) and aligned it with a bolt through the gear. Held the cam in place with a couple of C clamps and removed the bearing caps. Installed the exhaust cam lining up the drift marks on each cam gear. Installed the bearing caps. Haven't gotten this far yet but next would mount the timing chain gear on the exhaust cam and then pull the timing chain over it hopefully without moving the crank. God willing that will have the engine back together at TDC.

Friz

Engine went to OT with ease after removing the cams. Installed the cams and timing chain gear. Everything appears to be aligned. I would like to check it by rotating the crank 360. That should bring the #1 cylinder back to OT. If I remove the injectors can I do this without messing up anything?

Heck, just thought of something. If this is a 4 stroke I believe the crank rotates twice for a complete cycle. If so, I could be 180 out. Yes/no?

Friz

Yes, you could be 180 degrees out.

A few things to check before going any further.

# Did you compress the hydraulic valve lifters before re-installing?

- these will expand once removed by some margin.

# I don't have the timing figures to hand but my OM605 non -turbo was something like 15 degrees ATDC. This is important as you need to time cams, crank and pump together, this eliminates being 180 degrees out.

Look for the inspection port in the side of the pump, once removed you will see a notch which should be centre to the port.



Good luck.

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David


1996 Mercedes S124 E300TD - 129k - rolling restoration project -

1998 Mercedes W210 300TD - 118k (assimilated into above vehicle)

Well, that is not good news....but, any suggestions on how to get there? Not sure how the inspection port/notch on the injection pump fits into this. A little help please.

Friz

It's pretty straightforward, although a bit fiddly if you doing on your own.

The notch is attached to the small cam shaft on the injection pump. So basically when cylinder 1 is at ATDC on the firing stroke (cam lobes both pointing upwards) the notch should be visible in the port as shown.

You can buy a small MB tool which locates into the notch to hold it firm, but tbh it's easier to visually look.

Check to see you have the port as yours is a later model than my older OM605.

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David


1996 Mercedes S124 E300TD - 129k - rolling restoration project -

1998 Mercedes W210 300TD - 118k (assimilated into above vehicle)

sure

Screw the tensioner in hand tight to insure chain stays tight enough to stay on the sprockets.

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Jim

Alright shipmates, I am a happy camper! There is an inspection port on the 606 pump. Removed the plug and whadayaknow, the notch on the cam was staring me in the face. Rotated the engine until the cam notch came back into view and #1 at TDC. Cams are in the same position and the timing chain drove the cams without a problem So, thanks to you guys I can button this thing back up with confidence that it is time correctly. Thanks again, I sincerely appreciate the assist.

Friz

That is what we are here for.

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Jim