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Discussion Starter #1 (Edited)
There's enough info on various sites to DIY the various valve train components on the M119 engine, so the purpose of this post is to provide a few tips, some of which applies to the M119.98x only. I received much technical assistance from fellow member gsxr, as well as cheerleading from fellow member aam. I must say, he looks great in a skirt.


Timing chain stretch, the easy way (though less precise). This applies to ALL M119 engines.

The official way requires checking the timing stretch using a gauge to detect valve positions, but gsxr taught me a very easy, though much less precise, way of checking the stretch. (Btw, timing chains don't stretch so much as the holes on the links wear out and become bigger, and therefore the length of the chain assembly becomes longer.)

Step 1. Remove the right valve cover. DO NOT REMOVE OR SLACKEN THE TIMING CHAIN TENSIONER.

Step 2. Turn the engine (always clock-wise when standing in front of the car, staring at the car looking toward the rear), until the timing marks on the bell housing (harmonic balancer) reads 45°. (This is positions the engine to 45° before TDC @ cylinder 1.)

Step 3. At this point, you'll be 50/50 lucky. The camshaft turns half revolution for every time the crankshaft turns full circle. So every full rotation of the bell housing, you'll find that the cam shaft turns half.

Two ways to tell. One, see my picture of Step 1. If the cam lobes are pointing EXACTLY as the picture, then you're fine. Second, you'll find that the camshaft cog has little holes about 5-6mm drilled into it. There are several, and they all look the same, except one. That special one can be identified with some careful observation.

Step 4. When the chain is brand new (zero stretch), at 45° TDC, you should be able to put a 5-5.5 mm pin through the camshaft journey and into these special holes on the camshaft cog, at ALL 4 camshafts. I've used the valve cover bolt, and even allen wrench keys.

When there is chain stretch, each camshaft will be slightly off from one another, so you'll be able to get in only 2 or 3 at a time. However, for this exercise, you'll pin ONLY the right, exhaust camshaft (the right-most camshaft on the engine).

Since your chain should be stretched, you'll not be able to place the pin thru the cog. Turn the engine by hand until the pin easily goes in. Slowly nudge the crankshaft clock-wise by a degree or two until the pin goes in.

Step 5. Once it does, the pin will wiggle around a bit, so wiggle the pin left and right while turning the engine until the wiggle is more or less symmetrical (centered about the axis of the camshaft). At that point, read the number at the bell housing. Mine reads 3.5° past 45°, so the last camshaft is 3.5° late. Do this again several times (pulling the pin out and turning the crankshaft twice) to see if you can reproduce the number.

This is a ball-park method, but far easier to do. There's no official number for how much the timing can stretch, but I've read 6 degrees is the max.

Writing this up took longer than I expected, so I'll post other tips here next time.
 

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Very useful write up and photos :bowdown: We'll have to archive it somewhere for easy reference. It always happens that someone needs the information in the future, and then there's the battle to find it.

BTW If you don't have a º degree symbol on your keyboard, I'll gladly replace the * with º ;)
 

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very good details with pictures, I really like that

Did you camshaft chain plastic guide rails (all about 10 units) are in good shape?
Normally some will broke in a tiny pieces and clog in the oil hole that make engine overheat
 

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Discussion Starter #4 (Edited)
BTW If you don't have a º degree symbol on your keyboard, I'll gladly replace the * with º ;)
Man, you just had me searching half the morning for the "°" on my keyboard!

Kidding. I'm just lazy. Here's a DIY on that:

° Degree Symbol DIY

Step 1. Make sure the "NumLock" on the numeric keypad is off.
Step 2. Hold down the "Alt" key.
Step 3. While holding down the "Alt" key (step 2), push these numbers on the keypad in this exact sequence: "0," "1," "7," "6"

This procedure is often expressed as "Alt+0176"

If you're having trouble, take your keyboard to your dealer, and make sure they check your fluids and tire pressure. :p

Did you camshaft chain plastic guide rails (all about 10 units) are in good shape?
Yup, all are good. I replaced all of them over the years, except for that lower one by the crankshaft. That requires pulling the water pump and harmonic balancer, so I skipped it. The failure mode on these guide are fracturing at the pin locations, and the lower one is by far the biggest and beefiest, so I'm not expecting failure anytime soon.

Normally some will broke in a tiny pieces and clog in the oil hole that make engine overheat
Is this why you decided to overhaul your engine, to clear the oil galleries? How did the pieces get past the oil pickup screen? Do tell! The more I get into these engines, the more fun it gets.
 

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Is this why you decided to overhaul your engine, to clear the oil galleries? How did the pieces get past the oil pickup screen? Do tell! The more I get into these engines, the more fun it gets.
Look good for your DIY, really like it

My main problem for overhaul is the crankshaft is crooked, the other parts are just change by the age of 17 years that have to change, especially the gaskets that makes water and cylinder almost leak to each other

For the chamshaft plastic guide rails, when it broke it will stuck on the way to the oil pump, not even run to the pick up screen yet
I heard many of M119s that overheat from this problem
 

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Fantastic writeup & photos, jsap! Thanks for sharing! :thumbsup:



Has anyone ever heard of a 119 motor timing chain stretched beyond spec?
There is no published spec for M119 chain stretch. Mercedes did publish specs for chain stretch on some of their 6-cyl motors, the usual limit is 3-4°, however this is based on measurements more towards the middle of the chain. The method which jsap described above for the M119 measures near the end of the chain, relative to the drive gear. To determine M119 stretch in the middle of the chain, simply measure both left AND right exhaust cams, and split the difference. If you measure 6° at the right (passenger) exhaust cam, the left will likely measure 3°, so stretch between the two points will be approx 4.5°.

I've only measured stretch on a few M119's. One was 6° at the right exhaust cam, and I rolled in a new chain. Another was 3° and I left it alone. A third was zero (yes, zero, all four cams pinned at 45°!) which means a previous owner probably had a new chain put in at some point. My personal opinion is that 2-3° is probably normal after engine break-in (the FSM allows up to 2° deviation when measuring at the valves), and 3-4° is probably no reason for concern. At 5-6°, I'd probably want to plan a chain replacement. At 8-10°, it's overdue and should be replaced ASAP. YMMV, etc...

:sawzall:
 

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Hats off to you jsap for this amazing dyi. I am going to look into changing my guide rails in next few weeks and while at it I will also see if there is any timing chain stretch and then consider replacing it if needed. My question to you and others that have done this are:
1. Should I change tensioner preventatively even if I dont have chain strech? I have read stories of tensioner breaking and causing expensive damage.

2. Is the method of changing of the chain in M119 as described in the excellent diy directions (link below) for M116/117. If so then I might attempt to change my own chain rather than asking indy.
PeachPartsWiki: M116/117 Timing Chain Replacement

Thanks
 

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1. Should I change tensioner preventatively even if I dont have chain strech? I have read stories of tensioner breaking and causing expensive damage.
I wouldn't, but if you're rolling in a new chain, a new tensioner is generally a good idea. I have heard of very few M119 tensioners failing.



2. Is the method of changing of the chain in M119 as described in the excellent diy directions (link below) for M116/117. If so then I might attempt to change my own chain rather than asking indy.
Replacing the M119 chain is nothing like the M117, it's significantly more difficult. See photo below. You can not use pliers to clamp the chain to the sprockets to avoid jumping teeth. The FSM procedure says to use the blue wedges along with pressing the chain to the sprocket by hand, but this is a joke... even with two people, I had the chain skip a tooth four times while rolling the chain in. NOT fun. If your chain is not significantly stretched, I wouldn't replace it... up to 3-4° at the passenger exhaust cam is fine, IMO. The one I replaced was 6° which I deemed a bit too much. There is no official factory spec, as noted above in post #7.
 

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Greek God of the R129
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I wouldn't, but if you're rolling in a new chain, a new tensioner is generally a good idea. I have heard of very few M119 tensioners failing.




Replacing the M119 chain is nothing like the M117, it's significantly more difficult. See photo below. You can not use pliers to clamp the chain to the sprockets to avoid jumping teeth. The FSM procedure says to use the blue wedges along with pressing the chain to the sprocket by hand, but this is a joke... even with two people, I had the chain skip a tooth four times while rolling the chain in. NOT fun. If your chain is not significantly stretched, I wouldn't change it... up to 3-4° at the passenger exhaust cam is fine, IMO. The one I replaced was 6° which I deemed a bit too much. There is no official factory spec.

I think that there is a chain holding tool, that bolts in with guys to do the job easier, and it for one man job.
Look in Baum tool catalog.

Regards,
aam.
 

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I think that there is a chain holding tool, that bolts in with guys to do the job easier, and it for one man job. Look in Baum tool catalog.
There is no factory tool, but I have seen two aftermarket tools. The good one is shown here, but AFAIK it's out of production.

I've seen another that is small, plastic, and looks cheesy... no idea how well it works. It's Baum tool # M0037-119, shown in their PDF catalog on page 2, available online here. If anyone has used the Baum tool, please let us know what you think of it.

:thumbsup:
 

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There is no factory tool, but I have seen two aftermarket tools. The good one is shown here, but AFAIK it's out of production.

I've seen another that is small, plastic, and looks cheesy... no idea how well it works. It's Baum tool # M0037-119, shown in their PDF catalog on page 2, available online here. If anyone has used the Baum tool, please let us know what you think of it.

:thumbsup:
I haven't used any of this tools, so there is nothing I could add.

Maybe GSXR can comment on how to replace the guides.

Rivet or use the clips on the chain.

As this are important things on chain replacement, and more tools.....

Regards,
aam.
 

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Timing M119 from scratch

Thought I would re-seal the upper timing case covers and the cam advance on both sides of my 400E M119 engine since they leaked a lot. Right side was no problem. Installed the valve cover with a new gasket after removing the old one that was so brittle it came out, with difficulty, in several pieces. I've never seen one so bad! Before I put the cover back on I had a look at the guide I could see and it was there and complete. When I removed the left cover and peered in past the chain I saw that the top of the upper guide (not the one between the cams) had broken off and was laying up against the chain. So now this little job became a project I was hoping to avoid. After a restless nights sleep I started into it by again removing the right valve cover so I could "pin" the cams to loosen the chain to replace the guide on the left.....and well, since I was in there I might as well do the right upper as well PLUS the guides between the cams on both sides 'cause there was no way they were coming off in one piece. Everything is sooo brittle!! Hard to believe this is a Mercedes. Anyway, I got the big socket on the crank pulley and since I could see the 45' mark just to the right on the balancer I started to turn the engine backwards. That was a huge mistake. I hardly started turning it when there was a loud snap as the chain visibly jumped between the left cams. Clearly I need to turn this clockwise, which I did, but now the chain jammed. I could rock it back and forth but that was it. So, after much head scratching it was clear the only thing to do was to remove ALL cam spockets and remove the chain to look for the obstruction. Did that, turned the cams so all the valves were closed and once again tried to turn the crank while a friend held the chain and still it jammed. I resigned myself to pulling the front crankshaft cover off to find whatever had fallen in and was binding the sprocket. As a last resort, we took a small light on a wire and sent it down along the chain on both sides and discoverd the bottom of the upper chain guide on the right side had broken off and was wedged against the top sprocket. After we cleaned out the debris the chain moved freely. The guides have been replaced and now we need to time the engine from scratch!!! I didn't mark the chain / sprocket because I never got it to 45' with #1 at TDC. Can some direct me to a description on how to time the engine from scratch? What is the procedure? Thanks
 

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The guides have been replaced and now we need to time the engine from scratch!!! I didn't mark the chain / sprocket because I never got it to 45' with #1 at TDC. Can some direct me to a description on how to time the engine from scratch? What is the procedure? Thanks
Yikes! Sounds like a fun time. :D

Timing is easy. Set the crank to 45° BTDC (note: #1 piston will NOT be at TDC). Pin all four camshafts with the crank at 45°. Install the sprockets, chain, tensioner, and all guides (particularly the ones above/between the sprockets). Remove cam pins, rotate engine 2 turns, set to 45° again, verify that the cams can be pinned at or near 45°. If you did not replace the chain, the cams may pin closer to 40° and/or you may need to move the cams slightly to get the pins in place. They'll all pin right at 45° (±1°) with a new chain but almost never with an old chain.

Once that's done - use new OE/dealer valve cover gaskets (not aftermarket), install the gasket DRY with no sealant, and use new copper washers for all the bolts. Torque in stages to the 9Nm spec on all the bolts you can access with a torque wrench. For the upper head covers, only use the MB anaerobic sealant, not anything else, and definitely not RTV. Same for the cam solenoids - only the anaerobic sealant. (!!!) Otherwise you'll be re-doing that part of the job and finding out how fun it is to scrape off adhesive-type sealants.

The cam solenoids sometimes leak oil from between the two halves of the metal body, if you have time, clean the up and set them vertically on a clean paper towel for a day or three. If you find oil coming out the bottom edge... they'll probably leak on the car too. At least those can be replaced later without too much hassle (biggest nuisance is removing the p/s reservoir on the left side). Since your project started with fixing a leak from this area, I figured I'd mention it in case you still have a leak when you're all done. BT, DT on several of my M119's.

:thumbsup:
 

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Timing

Thanks Dave. I am waiting for one half of one of the upper guides from the dealer, it's on backorder.
I'm slowly starting to put it all back together. (I'm about to tackle that "hidden" bolt on the p/s pump.**&##@*).
When I put the upper covers on in the beginning I used Permatex 51813 anaerobic sealer. It was recommended by others on the forum.... just that the MB product is so expensive and I think it is made by Permatex / Loctite anyway.....Loctite 5900 ???? I even called Permatex and they recommended the 51813.
Also, would this be a good time to replace the chain and or the tensioner? There was some looseness to it (chain) at the spoket but didn't seem excessive.
If I re-use the tensioner does it need to be re-set...or doesn't it move in the absence of oil pressure to push it.... even with the chain removed?
Thanks again for the help.
 

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Thanks Dave. I am waiting for one half of one of the upper guides from the dealer, it's on backorder.
I'm slowly starting to put it all back together. (I'm about to tackle that "hidden" bolt on the p/s pump.**&##@*).
You've seen the photos here for the p/s pump bracket bolts, right? Don't forget that the front socket-head bolt for the bracket, below the reservoir, must have the threads coated with anaerobic sealant before installing. Ditto for a couple of the air (smog) pump bracket bolts on the other side. These go into the timing chain cavity with oil present. The FSM should mention the need for the sealant.



When I put the upper covers on in the beginning I used Permatex 51813 anaerobic sealer. It was recommended by others on the forum.... just that the MB product is so expensive and I think it is made by Permatex / Loctite anyway.....Loctite 5900 ???? I even called Permatex and they recommended the 51813.
That may be correct... should be Loctite 574 or Omnifit FD-3041. If the 51813 is equivalent, you're all set. I wonder how their 51531 is different? Use the same stuff for the timing cover to block surface as well.



Also, would this be a good time to replace the chain and or the tensioner? There was some looseness to it (chain) at the spoket but didn't seem excessive.
This is definitely a good time to replace the chain if necessary, before you put the valve covers back on. However you can check the chain stretch first (as shown earlier in this thread) and decide if it's needed. If the stretch is less than approx 4° at the right (passenger) exhaust cam, you could skip it for now. Rolling in a new chain is not fun but if you have the timing cover off, it may be easier to stick one in there with everything apart.




If I re-use the tensioner does it need to be re-set...or doesn't it move in the absence of oil pressure to push it.... even with the chain removed? Thanks again for the help.
No, the tensioner is not the ratcheting type and does not need to be re-set. It's oil pressure fed and spring loaded. Just make sure the tensioner is bolted in place BEFORE you remove the pins from the camshafts, to prevent a repeat of what started this in the first place.


:sawzall:
 

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Thanks for the link to P/S pics. I hadn't seen that before. I managed to get the bracket back in with the pump installed and DID NOT put sealant on the one upper bolt. Thanks for, the info. I have now sealed it and will look for more info on the air pump bolts that require sealing.
It isn't mentioned in the Alldata text, which gives RR info for the wrong pump for this car. Useless!! They only describe one pump and of course it isn't mine!!
Do you seal the guide pins? They pass into the oil passage.
Haven't got to the timing yet....maybe later to-day.
Stay tuned....thanks again
 
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