Hello all!

Today I will start the timing chain DIY on my 2005 SS C230K. I have 113k miles on the car and follow specific 5 to 7k oil changes on the car. As we all know there seems to be quite a few of these cars with stretching/failing timing chains.

I have done some heavy investigation on what might be going on, and based on my findings I concluded that there has been a change in timing chains from the beginning of production of the W203 to the current timing chain made available to this M271 engine. This leads me to believe that some design or manufacturing defect has been found, and updated since. It was quite hard to find, and some dealers actually deny that there has been a preceding part to the current timing chain. Also, it is widely known that there has been updates to the timing chain tensioner as well. On Hoggers thread I have cleared up as much as I know as far as part numbers.

Back on topic, tools. The necessary tools are:
I will update this as I progress with the job so please bare with me as this list becomes populated.

I have rented the timing chain crimper from a fellow member from peachparts.com forum. The tool cost was $20 and deposit was $200. The tool arrived at my house two days after I had sent him the funds through paypal. I can make this information available for those that are interested. I received the tool, and it is the original MB timing chain crimper.

I will not use the chain breaker used by mercedes, instead I plan on using a dremel with a steel bit to remove the lock pin.

This job will be completed between my brother, dad and me; therefore, I will not need the cam holder tool.

Today I will tackle the removal of the alternator to replace the timing chain tensioner and also the removal of the valve cover; however, I will not replace the tensioner until the new chain has been guided through. I then plan on tackling the timing chain removal and guidance of new one and rebuild of the parts taken apart tomorrow morning in hopes of finishing noon. This is of course, if all goes as planned.

I will provide the steps once the valve cover has been removed and images as I go by.

I will update this thread in real time, so for those who want to be tuned in, I plan on starting around 6:30 PM tonight.

First off, the goodies!



Timing chain crimper



Removing what I think is the intercooler muffler







Releasing the tension



After releasing the tension. The alternator removal actually isn't that hard. I removed the intercooler muffler to have space to maneuver the alternator out once lose. You do not need to release any coolant line whatsoever. Remove lower coverings under the car, remove intercooler muffler as previously shown, remove bracket holding upper air/oil line from the muffler. Once this is removed, disconnect the electrical plug from the alternator which is clipped on. After using a 15mm open end wrench remove the bolt holding the positive connector. Then simply remove the 4 T14 reverse torx bolts holding the alternator, no special tools here to be honest. Once done just pull the alternator out from the top.



Removing the upper and lower bolts



After removing the alternator, cleared off all wires from the valve cover.



Kinda tired right now, tomorrow I will take more pics of hoses that need to be removed from the valve cover.

Today's task was to remove the alternator and take out everything on top of the valve cover to make tomorrow's focus on the timing chain, tensioner and rebuild.

Update: Removal of cam cover





Valve cover removed:





From there I basically used a dremel with a tungsten carbide round tip and shaved down the pins. Making sure everything is completely covered with towels so no shavings fall off. Once broken I tied the new chain to the new one in the way I explained in the following pages of this thread.

 

sounds like a good plan jpman, please keep us updated

 

Thanks for doing this! I can't wait to see the final result. Good luck!

 

DIYs are always appreciated here
Did you experience some problems with your chain or just change it for piece of mind? My chain has never been replaced according to service book and now over 240k miles on the clock...

 

Sorry guys I have not been able to bring updates, currently stuck. I have the new chain in and pressed the new link. The cam lines are perfectly lining up and the crank pully is at 0. I put the new tensioner back in and tried to rotate the engine and it get stuck after rotating about 90 degrees on the crank. It seems like its interfering, but I don't understand why. The marks all line up. Open to suggestions...

One odd notation. It appears that when the pulley is at 0 degrees the first piston is not at the top. I keep running the pulley up to about 60 degrees and then the piston finally reaches the top. I don know what could be happening right now... Really confused at the moment.

 

Did u put the valve cover on before putting the tensioner in?
Do u have WIS?
If not what is your vin and I will look up the timing alignment procedure

 

Hi krazzdav, No I did not put the valve cover back in before rotating the engine manually. I wanted to check the timing marks after giving it a couple of spins.

 

pretty sure you are supposed to put your vc on first or the chain will be too tight....doesn't sound like your problem...i think the crank isn't supposed to be at 0 too but will pull the docs off wis right now for u

 

whats ur vin?

 

Did you rotate the engine before or after you installed the tensioner? Without the tensioner, the chain is too slack and will skip teeth, which is what happened to me during my chain job. Luckily I hadn't crimped it..If your #1 piston is not at TDC when the crank mark is at 0 then your crank is out of alignment, did you remove the crank bolt?
With the cam marks aligned and the crank pulley at 0 there should be no inteference.

 

Sorry I was wrong...I think I was talking about the M272 but here are some of the pertinent docs for the M271. Lmk if you need others

M271 Replace timing chain.pdf

M271 Draw in timing chain.pdf

M271 Check basic position of camshafts.pdf

M271 Set basic position of camshafts.pdf

 

RWDlifer, I rotated after I installed the new tensioner. The greatest issue I see here is that once I get to 0 on the crank pulley, the piston is still not at the top. It still has some to go. Its still not until about 60 degrees on the crank pulley that the piston starts to come back down. The crank pulley has never been removed and it has no scuffs from what I can see.

From what I could see, even if the crank pulley bolt has been removed, wouldn't it not make a difference since it has a notch for the pulley to slide in, making the position of the crank pulley only able to go in only one way?

 

krazzdav thanks much for the documents! All my procedures have been straight on par with these documents. Stuck at the moment wondering if something is up with my crank pulley.

 

Dang bro that sucks.....yup sounds like the balancer spun. If you see cracking on the elastometer or empty spaces is an indication it is bad. (between the inner mounting surface and outer band w/ timing marks)

Part# is A2710300003

Here is docs for that
M271 Remove_install belt pulley_vibration damper.pdf

M271 Pull off belt pulley _ vibration damper.pdf

M271 Install front crankshaft radial seal.pdf

 

But how would that be possible if it was OK before and he didn't mess with the crank pulley??...

Jpman, did you check if the key-hole is opposite the O|T mark on the pulley?

 

Thats what I've been scratching my head over. The problem is when I first opened the valve cover, I spun the engine without the tensioner which of course then made the chain jump teeth. So I wasn't able to verify if the car had lost timing or not. So basically I had to go to the lets get the timing as if it was the first time method.

Spun the chain without moving the cam gears by just rotating the crank pulley as I ran the new chain through. Once the new chain had been drawn in I set the crank to 0 and thought the piston was at is highest point while flashing a light inside the hole, but actually trusting that nothing was wrong with the pulley. and proceeded to bring the cam gears into timing with two 1 and 1/16 sockets and torque wrenches to bring them in. I got the marks dead on and closed the timing chain and crimped the master link. Once that happened I brought in the new timing chain tensioner in and tried rotating. It rotated however, at about 60 or 90 degrees a turn, the crank got really hard and stopped immediately and brought it back a little. So here I am.

After trying to break my head I decided to put a 3/8 12 inch extension in the spark plug hole and realized as I cranked the engine more it kept on going up , past 40 degree mark on the pulley. I saw it finally stop going up and started coming down at around the 60 degree mark on the pulley.

By the way, If its worth mentioning I measured the distance across both chains and it seems that if the old one was stretched it wasn't by more one fourth of an inch. So that makes me feel more comfortable.

Now I'm staring to consider if it is the crank pulley to just take it to a shop and have them replace the pulley and put it all back together. This should have been a simple job but is starting to go south from here, loosing a little faith in this project.

I really wanted to bring some information onto this forum and have tons of pics, but I am a little disheartened at this moment with this road block.

 

VVF what is the key hole?

 

It was like that before is what I am willing to bet. The only way to know if it had this problem before starting the work was to have lined up all of the marks prior to removing anything....thus only now after finishing the job was it noticed that the crank mark had spun from where it should have been. Now if TDC was checked prior to starting the job then it is something else...but doubtful

 

He is talking about the key/slot that the pulley has to align on the crank with. It looks like it is supposed actually be lined up with the 0|T mark though---or exactly opposite the U|T.

 

looks like the U|T mark can be used to tell if the balancer spun from it's original position

 

I see the U|T mark, but I think the nut holding the pulley covers that mark, or at least thats how it looks from the angle I am looking from. Is it me or is that true?

 

Something is not right. It is not possible on an inteference engine to rotate the crank pulley while the cams are in place (I'm assuming you did not remove the cams). The crank pulley and the cams have to be moved in sync to feed the chain. Hate to be the bearer of bad news, but if this is the case (ie crank pulley turns with cams in place) then you have bent valves. Plus, if your #1 piston is not at TDC when the crank pulley mark is at 0, then your harmonic balancer spun as well.
I'm guessing the car was running before you started this job. When you removed the tensioner, did you rotate engine by hand or did you jog the starter? I can't figure out how this can happen...

 

Something isn't right. Thats what I'm thinking. Before I started this job, the car ran perfectly fine, not one hiccup. Could it be possible that when I was rotating the crank the valves were at their highest point? meaning furthest possible from the piston? I never felt resistance rotating the crank, at least not as much as what I feel now. Ever since I started the job, on Friday the engine has not been turned by the starter, it has all been rotated by hand by means of the crank pulley nut.

 

The bolt would cover the key way so couldn't see that without taking the bolt out. Can you feel if there is a notch along the inner part of the pulley that the U|T mark would have lined up with? Sounds like should be about 60deg off one way or another from what your saying. You can always remove the bolt but will need an impact or hold the pulley in place while you do it. You can then retorque it if everything looks right but I doubt it will.

And RWDlifer has a good point about the interference of the piston and valves. You will find out if any damage was done after getting the TDC aligned back up.
You let the cams go all together correct? Maybe you got lucky and the cams "at rest" position had just enough room for the pistons to clear them all.

Don't take it to a shop :P You came so far haha Now all you need is a puller for the crank pulley, and the seal installer (or a huge socket that will clear the crank shaft) and redo the timing chain alignment

 

I think you are fine with the valves and they had enough clearance in the "at rest" position so wouldn't worry about that since you did do it by hand. You would have had to force it to cause problems.