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Club smart Car > Technical Discussions > How-To: 450 Model, 2005-2006, diesel
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dieselkiki
Hi folks, smile.gif

There's some of you who did replaced a timing chain or the oil pump chain on an OM660 CDI??? unsure.gif

The engine on my 2006 smart CDI make a noise of "slack" chain in the front cover. I thought that was normal but when a friend come at home yesterday with his smart... her engine was very quieter than mine!! Since I understand it I'm very worried about a timing/oil pump chain failure. sad.gif

So, I dont want that one of that chain break on the highway. I want to removed the front cover to inspect both chain. Somone have some information on the procedure, torque of the bolts (crank damper, front cover, vacuum pump etc...). So, any help will be welcome!

Thanks

Dom
Silver
I know not of what I speak, but (there always is a but) it's election time so why should I be different from our leaders?
Again, I don't know if it's the case with the Smart engine (and here's the but again), but on a Merc diesel one sets the camshaft pulley at zero then if there is no chain stretch the crankshaft pulley will line up with its zero point. The the amount that it is off is the degrees of stretch. It's been a while, I think that four degrees of stretch is starting to be bad and at seven, it's about to break.
Oh, I just realized that you're a stone's throw from me. Who do you use for servicing? Also, for what it would cost, I would go to Rive-Sud and have it diagnosed. It would be a $50 well spent.
Mike T
I am glad you noticed this sound now, before it is too late. I think the dealer would charge about $1000 for the job. The engine has to come out.
Schwalli
I'm confused.... is this a "normal" thing on the list? I thought only timing BELTS need to be replaced.... Cost me (including waterpump) $1400 on my Eurovan...
Alex
As a rule, the timing chain problem is due to the plastic tensioner breaking, then the chain slaps around until it too breaks.As long as the tensioner holds up there should be no chain problem for the life of the engine. An easy check is to feel the chain tension through the oil filler cap with a slim screwdriver or other thin metal rod. There should be no perceptible slack on either side. The oil pump chain can't be checked without dropping the pan.
Both chains are sensitive to oil quality, as is the rest of the engine. Lots of oil changes! Turbos are hard on oil, diesels are hard on oil. 8K km is pushing it for maximum engine life, 5-6K would be better.
Mike T
If you ride a bicycle it is easy to know how much a chain can stretch, especially because a bike chain is a simplex (as opposed to duplex) chain, just like on the smart. I think chain stretch could also be an issue with valvetrain failure if it gets extreme, but usually the tensioner could take care of the slack. I asked TPM about prophylactic chain replacements and they are not sure whether it's worthwhile or not, even at 200K km. But if the chain is noisy now, it is time.
houseofdiesel
Timing chains only last the life of the engine in terms of warranty or dealer terms...chains will not last the life of an engine in normal service where an engine lasts 20 years or many hundreds of thousands of kms. The chain is subject to some hard use on the cdi, I have seen an engine apart and it was filthy inside the chain cover, lots of debris the size of a finger nail just sitting inside the cover, black carbon stuff hard and flakey. I would guess the chain life to be around 200kms, but the plastic shoes on the tensioner/guides might not last that long, recent plastic parts on german engines are only lasting 6-8 years and 100-200kms. We see lots of cam adjuster shoes breaking on VW/Audi gas engines, lots...but diesels don't usely have the heat cycling that gas engines have.
I think frequent oil changes are a big factor with the cdi staying clean inside, the cars are just getting old enough now for the plastics to degrade and show problems, but maybe oil changes or quality was a factor and the chain is simply stretched to far. Make sure the cogs/teeth are still good!
lebikerboy
Same as a bicycle the rollers inside the chain wear down and the chain is said to have "stretched".
On a bike keep your drive train clean, use the proper lube and your chain will last a lot longer.
On the smart change your oil/filter at least as often as MB recommends or more if you desire and it also
will last longer...
dieselkiki
QUOTE (Alex @ Mar 27 2011 - 01:27 PM) *
As a rule, the timing chain problem is due to the plastic tensioner breaking, then the chain slaps around until it too breaks.As long as the tensioner holds up there should be no chain problem for the life of the engine. An easy check is to feel the chain tension through the oil filler cap with a slim screwdriver or other thin metal rod. There should be no perceptible slack on either side. The oil pump chain can't be checked without dropping the pan.
Both chains are sensitive to oil quality, as is the rest of the engine. Lots of oil changes! Turbos are hard on oil, diesels are hard on oil. 8K km is pushing it for maximum engine life, 5-6K would be better.


Thanks about it Alex. So, the timing chain look to be in good condition. No delay between the rotation of crankshaft and the rotation of the camshaft when I turn the engine foward/back. I take a long screwdriver to check the chain and it look to be ok. No loose. But the noise is always there and I can't see the tentioner. I must remove the damper pulley to remove the front cover. Some of you have already remove it?? So... I'll call to mercedes-benz rive-sud tomorow to now the cost of both chain, guides, sprocket and tentioner. I'll replace "ALL" by myself. It's very meaningless that a mercedes-benz diesel engine timing chain must be replace at 116000km. My old 240D run about 730000km with it original timing chain. I can't understand! Where's the reliabilty???
I'll replace it by myself cause Mercedes-benz mechanics are too incompetent and unprofessionals. They broke my car far too often. I can't be worse than they! dry.gif

If somone have the torque of bolts etc... it will be very appreciate!

N.B.: I'll try to make a video of the engine running tomorow.

Thank you for your posts and sorry for bad vocabulary. smile.gif

Dom
Alex
If the chain is tight, it shouldn't be making noise. Are you sure that is the cause of the excess noise? No point doing all that work if it isn't the problem!
What else could it be? Lifters? External? Air leak? Do some more investigation before committing to this.
bilgladstone
QUOTE
N.B.: I'll try to make a video of the engine running tomorow.

I have been meaning to do the same as my smartie is getting pretty tick-tick-ticky too. I think it's more like valves or lifters rather than timing chain. Maybe I'll try for it tomorrow and we can compare!

Bil sun.gif
Mike T
QUOTE (lebikerboy @ Mar 27 2011 - 06:22 PM) *
Same as a bicycle the rollers inside the chain wear down and the chain is said to have "stretched".


They do that but they also do stretch too. The distance between pins in a chain is exactly 1 inch and I have seen some 10,000+ km bike chains with 10% extra length between pins! So I am certain this happens on the smart's oil chain and cam chain too.
Alex
Chains don't "stretch".
They most certainly wear, extra clearance in all those holes and pins makes the chain longer indeed, but if you measure any one link it's exactly the same dimensions as new. Except in hole diameters! You do measure the length of a worn chain to determine if it needs replacement, a rule of thumb in industrial chains is 1/4" per foot is acceptable.

BTW, a badly worn chain won't fit a sprocket tightly anymore. If there is no slack on either side of the chain the tensioner is probably fine, if you can't find slack in the middle of the sprocket the chain is OK. Even if a worn chain is pulled taut around a sprocket due to chain wear all the tension is taken by 1 or 2 teeth on each side and in the middle the chain can be lifted off the teeth a bit. Best to repeat these tests with the chain in several locations.
Lacking either of these symptoms I suspect the noise is caused elsewhere.
houseofdiesel
Could be your lifters are getting old (hyd elements in mercedes speak, under $20 each), they tick away when worn, or maybe you have bad fuel? Is the noise around for the last few tanks or just recent? Many things can cause a diesel to run differently from another, injectors, fuel, oil, lifters, chains, air mass meters, clutch adjustment, leaking intercoolers, worn turbos etc.
Very few mercedes diesels got away with the original timing chain, saw many jump or break when I was a coop student working on diesels, usually before 400kms. That was awhile back now...
dieselkiki
QUOTE (houseofdiesel @ Mar 28 2011 - 07:28 AM) *
Could be your lifters are getting old (hyd elements in mercedes speak, under $20 each), they tick away when worn, or maybe you have bad fuel? Is the noise around for the last few tanks or just recent? Many things can cause a diesel to run differently from another, injectors, fuel, oil, lifters, chains, air mass meters, clutch adjustment, leaking intercoolers, worn turbos etc.
Very few mercedes diesels got away with the original timing chain, saw many jump or break when I was a coop student working on diesels, usually before 400kms. That was awhile back now...



- Injectior # 3 are just replaced
- Turbo & intercooler are 1 year old
- air mass meter (witch one??? There's no air flow meter on smart CDI, sorry.)
- Clutch ajustement are done at each oil change = ok

You know, I'am a 10 year diesel mechanic and I have a good idea of what a bad injetor, turbo etc... do. I'm almost convinced that one of the 2 chain (tentioner/guide) are the noise source. I just want to knew if somone had removed the damper pulley and the timing cover on a OM660. I need the torque, the procedure and if there is someting to be careful when we do that kind of job. Could somone give me this information? That's all what I need at the moment. Thank you.

I just called to mercedes-benz Rive-sud to know the prices of the parts I supposed to be failed. It's look like this:

- Timing chain = 95$
- Timing chain sprocket (cam) = 78$
- Timing chain sprocket (crank) = 44$
- Timing chain tentioner = 66$
- Tentioner guide rail = 23$
- Timing chain guide = 22$
- Front crank seal = 14$
- Dip stick o-ring = 2$
- Oil pump chain kit (2 sprockets, chain, tentioner, spring) = 200$

I hope I'll dont need all of them. dry.gif

Dom
Mike T
QUOTE (Alex @ Mar 28 2011 - 06:15 AM) *
Chains don't "stretch".

Oh yes they do! I should have kept my old 15000 km Rohloff chain from my bike to show you, the distance between pins was 10% over the 1 inch original spacing. The pin holes were not oblong, it was not wear (if the holes were oblong the pins would have fallen out and the chain would have soon been in pieces, it was the metal of each link that had stretched by the 10%.
Mike T
Dom, if you are going to do this work, you probably should buy all that stuff and do it......
Schwalli
@Mike: did you "just" have the Rohloff chain or also the speedhub?
dieselkiki
QUOTE (Mike T @ Mar 28 2011 - 10:20 AM) *
Dom, if you are going to do this work, you probably should buy all that stuff and do it......


I'll begin to remove the timing cover to take a look at chains and tentioners before wasting all that $$$. Because most of that parts are not refundable. rolleyes.gif So... I'm not realy satified of my "smart" product. dry.gif Bad service, expensive maintenance fees, bad reliability... I'm vexed. angry.gif

I'll probably post somes pictures when I'll open the engine.

Thanks for all. wink.gif
lebikerboy
Chain wear and care evokes never ending discussions, especially for new bicyclists who are not happy with this dirtiest of bicycle parts. This leads to the first problem, of whether there is a best (and cleanest) way to care for a chain. Among several ways to take care of a chains, some traditional methods are the most damaging while others work to prolong useful life.

A myth that is difficult to dispell is the story that grease on a new chain, fresh out of the package, is not a lubricant but rather a preservative that must be removed. This piece of bicycling myth and lore thrives despite its illogic.

Riders often speak of "chain stretch" a technically misleading and incorrect term. Chains do not stretch, in the dictionary sense, by elongating the metal by tension. Chains lengthen because their hinge pins and sleeves wear. Chain wear is caused almost exclusively by road grit that enters the chain when it is oiled. Grit adheres to the outside of chains in the ugly black stuff that can get on ones leg, but external grime has little functional effect, being on the outside where it does the chain no harm.

The black stuff is oil colored by steel wear particles, nearly all of which come from pin and sleeve wear, the wear that causes pitch elongation. The rate of wear is dependent primarily on how clean the chain is internally rather than visible external cleanliness that gets the most attention.

Only when a dirty chain is oiled, or has excessive oil on it, can this grit move inside to causes damage. Commercial abrasive grinding paste is made of oil and silicon dioxide (sand) and silicon carbide (sand). You couldn't do it better if you tried to destroy a chain, than to oil it when dirty.
Alex
The holes in the outer links don't wear, the pins are a tight fit and peened in place so no movement there. It is the pivot point on the inner links that wear. Steel doesn't stretch by 10%. Period. Steels vary somewhat in properties, but generally reach their elastic limit at less than 2% elongation. Once you reach the elastic limit they stretch to the break point with very little additional strain, so in practice you never come close to the elastic limit unless you want certain catastrophic failure with only a slight overload. Certain fasteners with very precise installation procedures are meant to enter the elastic limit zone, but only once!
Sorry, Mike, with all due respect (a lot) but you're off on this one.
dieselkiki
Comme promis, voici la Vidéo.

http://www.youtube.com/watch?v=10csSaTkbYQ
ogopogo
QUOTE (dieselkiki @ Mar 28 2011 - 06:21 PM) *
Comme promis, voici la Vidéo.

http://www.youtube.com/watch?v=10csSaTkbYQ

bonjour Dom. That doesn't sound like chain slap to me but my limited experience with timing chains is older gassers. I am most interested to follow your results here as I just purchased the same vehicle.
Schwalli
This sure sounds like : A SINGER sowing machine biggrin.gif
Mike T
QUOTE (Schwalli @ Mar 28 2011 - 11:41 AM) *
@Mike: did you "just" have the Rohloff chain or also the speedhub?

It was bought in 1992 and on my Raleigh Super Course with normal derailleurs for over 10 years (bad me!), no speedhub.
Mike T
QUOTE (Alex @ Mar 28 2011 - 03:13 PM) *
The holes in the outer links don't wear, the pins are a tight fit and peened in place so no movement there.

I think my explanation was bad about the links themselves stretching, all I was meaning before is that the distance between pins was elongated 10%, of course it was a whole pile of links across which I was measuring, not just one!

lebikerboy explained what I was trying to say.....
Mike T
Dom that car sounds sort of normal to me, maybe a bit of a a "sliding" sound....I am not sure what it is, are you sure it is coming from the area of the chains? It even could be the alternator...?
dieselkiki
QUOTE (Mike T @ Mar 28 2011 - 02:52 PM) *
Dom that car sounds sort of normal to me, maybe a bit of a a "sliding" sound....I am not sure what it is, are you sure it is coming from the area of the chains? It even could be the alternator...?


Yeap! The noise come from chain housing but... most in the bottom than from upper cover. Maybe the oil pump chain. I dont know. I'll open the engine when I'll be abble to lend a car for a week.

For the alternator, it a fact, even if I have replace it last spring, the front bearing turn rough. It's the reason why I removed both belts last weekend to make a better diagnostic. But unfortunately, the chain noise was just more audible and clear.

Thank you for your comments.

Dom
Mike T
Maybe your oil pump chain tensioner is dead, so I think you are doing the right thing!
dieselkiki
Yeah but I was hoping to find some technical information here. Unfortunately... I'll must search somewhere else. sad.gif
Alex
We're trying to help, but unfortunately Mercedes is rather stingy with the technical details. There was a thread way back with some good photos of the oil pump chain, I can't recall any detailed info on the timing chain. It looks like the pan could be dropped with the engine in place, that would make the oil pump chain an easy job, and let you inspect the timing chain from a different perspective and on the other sprocket.

The video doesn't sound terribly scary to me. Bit of a hissing sliding note. In person has much better sound quality, perhaps there's something I'm missing. Good luck, keep us posted. I want to keep my smart for a long time yet, and any information gets filed under "valuable".
Cheers.
dieselkiki
So... the newer mercedes diesel cdi dont realy have the same reliability than older one. dry.gif Piece of &*$?%?!!! GRRRRRRRR!!!!!


Mike T
I can't see what's wrong in that photo.
Alex
Is that a missing tooth or more on the sprocket? And a LOT of slack in the chain for sure. In any case good on you for getting on it before catastrophe ensued.
What is the oil change history, and driving conditions? A lot of city trips?
I want to know when to do a preemptive on mine, sitting just shy of 140K and rising fast. I do have the favorable climate, lots of highway and 5K oil changes, so I'm not too worried. Yet.
Mike T
I didn't see what was being photographed clearly enough to tell if a tooth was off, but doesn't the chain tensioner use oil pressure to take up slack in the chain?.....or is it reliant on spring loading only (in which case it is shot)?
dieselkiki
My car have only 116000km. Almost just highway km. I change oil every +/- 7000km with mobile1 0W40 grade full synthétique. All filter are replaced in time, antifreez, transmission oil, belts etc... I taking care of that car like no other one. I just can't understand!! It's a real crap!!! My worst car ever!! sad.gif The oil pump sprocket is dead! All the thoots are off by worn. The chain is slack and the tentioner look like new. What's wrong?? Spring are there and in good condition. The timing chain tentioner look to be activate by oil pressure but the oil pump tentioner is activate by a spring. I realy don't know what's happen here. No one can saying me. I think that is just because it's a bad engine desing error or a fail in material. Am I the only one who it happen??

So, I'll never see the mercedes-benz diesel engine in the same way. I tought that was reliable and indestructible. Humm-humm... WRONG!!! dry.gif
Mike T
If you change the sprocket and chain, it should be OK for many km to come, no? I mean, if the worn sprocket teeth didn't cause the oil pressure warning light to go on, the oil pump was always driven when the engine was on, the engine should be fine once you replace the bad parts.

I have heard of two other cars with this problem, one in the southern USA and one in Canada, so it seems to be rare. More common are valve lifter and valvetrain problems, but that too seems quite rare.

My older smart has about 193,000 km on it and the oil is normally changed at between 9000 and 10,000 km. So far, so good. I just changed the oil two days ago at 9100.....

Even modern Mercedes CDI engines (for example, the 350 CDI) are probably not as long-lived or reliable as the old indirect injection M-B and Peugeot diesels.....
bilgladstone
Clickety-clack, clickety-clack. Camera ran out of memory before I could get underneath!


Sound is worse when cold. This is at 70Cwt.

More anon.
Bil sun.gif

P.S notice some critter is stashing seeds in the injector wells!
bilgladstone
QUOTE (dieselkiki @ Apr 1 2011 - 10:36 PM) *
... I think that is just because it's a bad engine desing error or a fail in material. Am I the only one who it happen??

I think I have the exact same problem! 100,100km angry.gif

See here: LINK
dieselkiki
DAMN!!!! I must remove the timing chain to change the oil pump chain!!! dry.gif The oil pump chain is under the timing chain. Why they did it??? angry.gif
bilgladstone
With the cog messed up like that, Dom, did you find any debris inside there?
smart142
I have an engine with the same missing teeth oil pump sprocket. Did all those metal grindings go into the internals???

I took it to a machine shop to have it all checked. Should find out soon if it has to be junked or reused.
dieselkiki
QUOTE (bilgladstone @ Apr 13 2011 - 02:41 PM) *
With the cog messed up like that, Dom, did you find any debris inside there?


No debris found. Just some microscopic metal flake in oil when you check the oil pan at differents angles with a light.
cadillacman
Following Bil's lead I started a PhotoBucket account, and uploaded a video/sound

http://s1142.photobucket.com/albums/n609/M...g2011-04-12.mp4
dieselkiki
So, I just came back from buying my job parts. I'll do the job next weekend if weather is good!

So, I bought the oil pump chain, both sprockets, the binder with its spring. I also bought the front crankshaft oil seal because I must remove the pulley damper. I have some gasket maker to put back the front cover. I hope I wont need some other parts during the job. huh.gif








dieselkiki
DAMN!!! I break one of subframe bolt in the tridion and I break 2 ratchet + my socket to unsrew the dampe pulley bolt. dry.gif It's an hard job! sad.gif
bilgladstone
Yikes! But we know you will conquer!
Alex
"The first 90% of the project takes the first 90% of the budgeted time and money.
The last 10% of the project takes the other 90% of time and money".
-Murphy.
dieselkiki
So, there are a good and a bad news. dry.gif

Good news: The noise wasn't from the chain case.

Bad news: I dont now where its come from. sad.gif


But... I'll show you what I did on that crappy car.




First of all, I removed the oil.






After this, I removed the the injector connectors to be abble to removed the valve cover.





Removed the back pannel.



So now... the f*cking valve cover can't be removed by the upper side and not more by the under side.... DAMN!!! I must drop the engine to have enought room to remove the valve cover.





So, now, the valve cover is remove and I can take a look at the timing marks.





After, I removed the pulley damper to be abble to remove the front cover. HUUUUUUGE job! I break a lot of tools!! Ha!!








So, after front cover removing, the bad news occure!! Nothing wrong on both chain!!! 5h on job for nothing!! I'm very angry to have waste my time for nothing!! angry.gif

Both chain are ok! All sprocket are ok! All guides and tentionner are in good condition... where is the problem?? Hello??? No body can help?? Hmmm... unfortunately, not realy. No body know these OM660 engines. dry.gif Even dealer dont know. I felt alone! unsure.gif

















So, thanks for all guys!! But I think that I'll sell that car. It's too hard to get informations and part. We really are too dependent of dealer when we are a smart fortwo owner. And this car is a "BITCH" to work on!! It's enought!! I sell it as soon as I can!

Good night! cool.gif
bilgladstone
We are very grateful to you for sharing your experience and posting the photos. It is a shame that the solution to the problem continues to elude you. And me too, since I have a bothersome noise in my engine as well!

Better luck to you in future...

Bil senile.gif
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