Splint3048

Hi,

Just in the process of replacing a timing chain on my W211 e350 and I realized I don't know the exact positioning of all of the color coded links when the crank is at 40° ATDC. It's not a major issue as there are markings for every rotating components and the colored links are a secondary indicator.

I took a few photos before breaking the chain and one link lines up with the 12 o'clock position on the RH intake cam adjuster (3 and 6 o'clock are on the plane at the top of the cylinder head. I should be able to get it properly set up with that information alone but the cam adjuster has been removed and it might take a couple of attempts to get it reassembled perfectly.

Anyone have any data on the correct location of the colored links?

Thanks

kjb55

mcleantmw

How many miles do you have on your vehicle; and, why are you replacing the timing chain? Did it break? I have 184,000 miles on my vehicle and I was wondering when I need to start worrying about replacing the timing chain........it's apparently not a scheduled maintenance item by MB recommendations.
Thanks
Tom

Splint3048

Thanks kjb55, my engine is the quad cam version, do you have a diagram for that? Are they the same?

mcleantmw, I wouldn't be concerned about your chain unless you are seeing codes relating the the engine timing.

The issue I'm facing is that P0016 and P0017 errors were coming up which from what I could find in the net was the dreaded balance shaft issue. My suspicion was further backed up when doing a quick check by setting the crank to 305° and sighting the part number inscriptions through the cam position sensor holes (they weren't exactly central).

I pulled the engine out and tore it down only to find the balance shaft gear was in excellent condition. I assumed the chain had stretched and did a check of the crank angle when the valve was open 2 mm. The specs only give an expected value, not a range where the chain is serviceable so there was a bit of guess work in deciding whether the chain was in fact stretched.

I figured given the work I'd done so far, replacing the chain was a reasonable step even if I don't know for certain that it's stretched. I guess I'll find out soon enough if this prevents the error codes from appearing.

Chain stretch is apparently pretty rare in the w211 M272 engines so I wouldn't be to concerned. It's pretty unlikely that it will just break without spitting out some codes to say the crank and cam are not in the correct positions relative to each other.

Edit: my car has 110,000 km on it so it hasn't done that much work.

knowbenz

So are you doing the balance shaft anyways since its all torn apart?

kjb55

I will search WIS tomorrow (Monday) for the M272 pic. However, I think this picture might still be correct as the intake cams drive the chain. See the attached bulletin in case you haven’t already - under failure symptom 1, there is a specific note about rare cases of the timing chain stretching and being the fault when the gear inspection shows no wear.

I’m at the same point as you, although no fault codes. My 2006 has only 26k miles - but i want the issue put behind me as I plan on keeping the car and by the time I would probably part with it (8-10 Year’s) one of my kids will probably take it, and the chances of the problem arising will be much greater.

Engine is pulled and I’m in the process of disassembling the engine to get at the balance shaft. I have a good collection of WIS documents if you need them. Let me know.

Splint3048

Knowbenz, prior to tearing down the engine I was only aware of build date and VIN methods of identifying bad balance shafts. I was unable to find a working web site which could tell me if the shaft was bad using the VIN, there were some web sites previously but all now not working or shut down. My engine was a September 06 build, the last bad balance shafts were installed in October 06 but below a certain engine number. I later learned about the engine number and found that my engine was outside the bad batch of shafts.

With the conflict of engine number and build date I contacted Mercedes Australia who surprisingly were unable to give me an absolute confirmation one way or the other as to whether I had a bad shaft. The suggested I contact the dealer where it was last serviced which I did and they were also unable to give me confirmation. MBA did however suggest that the engine number would be a more reliable indicator than build date.

As the vehicle is somewhere near the middle of the range (kilometers) at which the shaft should fail and it hasn't shown any signs of wear beyond what would be regarded as normal wear given it's age I have decided not to put in a shaft.

Kjb55, thanks. I can give you one tip which may or may not be applicable to you. When I used a slide hammer to extract the pin which locates the chain tensioning guide, I tried like crazy and it wouldn't budge. I even tried heating the mounting point with a hot air gun in the hope the loctite would soften and the aluminium would grow and open the hole a little, no luck at all there. I ended up getting a flat plate of steel about 200 mm by 80 mm by 10 mm and drilled a hole in the centre through which I put a long 6 mm bolt with a nut on it and pulled the pin out using that. It worked like a treat and came straight out.

kjb55

I checked all the documents for the 272 engine, and the same diagram is used.

Redwood415

That is abnormal for that motor? We have not seen a single chain job on M272 or even older 3 valve M112 for that matter. Our personal has 302K miles, original chain and heads have never even been off. That was more common with older 4 cam M119 (Mercedes's Best Engine Ever)


Cheers

knowbenz

Thats not abnormal at all. We do them regularly usually the gear wears out and it gets a new chain with it. we have done quite a few 112/113 as well