When is it time For a new Chain?

[dudu]

Does the M116 motor suffer the EXACT same problem?

I mean, I know it also suffers possible engine destruction but is it exactly the same as the M117?

A couple years ago i bought a book from mercedessource..."How to prevent catastrophic engine failures on early V8" and it says something like this "on early M117 and also M116...."...

So, i am afraid the answer is "YES", the suffer from the same "desease"...

Regards.

[bolbol]

How is the timing chain installed initially ? Is it by setting the notch on each camshaft to the marker and having the vibration damper at zero, then attaching the chain ?

I once saw a mechanic, after attaching the new chain to the old one, he had two guys  holding the chain to each end firmly but away from the sprockets, then he moved the crank slightly to zero marker , then he nudged each camshaft till it matched the marker on each tower, then he removed the old chain and attached the new chain with a link...

Assuming that you have no chain attached at all; after a major work  was done, Is this the right way to install the timing chain ?

bolbol

[CraigS]

Procedure is here -  http://handbook.w116.org/Engine%5C107%5CM117_45%5C05-320.pdf

[Sev]

Ok guys, what are the usual signs telling you need a new Timing Chain? Is it going to Rattle all the time at the front? will it rattle When cold only?  Does it run rough? just curious because the majority of my Mercs have the m117, none of the cars are acting strange... just curious just to be sure.

when the old one has over-stretched.

no, it's not, so long as tension the timing chain tensioner appropriately

if your timing chain is loose, it will not rattle or run rough. if it's significantly loose, it will just break, causing the plastic guide for the chain to break, and fall into the oil pan.

then you're royally 'effed', if you come from a country that has royalty, like Australia (they have a king and queen there, don't know if you knew)

[Brian Crump]

It is usually possible to hear the chain rattle for a second or so at start up. Thus applies even when the tensioner is OK.
Regards,
BC

[bahnstormer109]

youre right BC, you can hear the chain rattle on start up.

my 109 3.5 did it on hot start ups when i got it so i had the chain etc replaced. its only done 12,000miles on the new chain and still very rarely i do hear a rattle on hot starts. maybe once or twice so far. had it checked but they reckon its fine.

i think i heard the 450 rattle the other day on a hot start. havent heard it before or since so may have imagined it.

[OzBenzHead]

[...] havent heard it before or since so may have imagined it.

Paolo:  Paranoia is one of the "joys" of owning old(er) cars - though I must admit to experiencing very little paranoia with my Benzes compared with other machinery I've owned.

Imagine how para you'd be driving a $50 EH Holden with a gearbox full of banana skins and the gear linkages held together with bent 2-inch nails!  (Reminiscences of my student-poverty days!) 

I'll have to listen more carefully for chain rattle, as I can't say I've ever been conscious of it on my Benzes.  Yet.

[koan]

On the chain rattling sound at start up, I would be surprised if it would be heard from inside the cabin.

Isn't a rattling sound at start up most likely excessive valve clearance cause by a leaked down hydraulic lash compensator (lifter), the noise fading as it pumps up, especially if it is only intermittently heard?

If it is a chain rattle that can be heard in the cabin I wouldn't risk driving another mile with it.

koan

[bahnstormer109]

Koan, on the 3.5 i could hear it clearly inside the car. is the sound of the chain slapping against the motor. when you hear it you know its time to get it looked at. 

[Andrew280SEL]

Is it ever possible, do you think, to hear it during acceleration or just cruising?

I'm guessing not, because of engine noise. My 350 occasionally has a slight vibration I think when accelerating when cold, but I think it's only a universal joint or whatever. Although it seems like it's only there when cold....

But a loose timing chain wouldn't cause any vibrations though anyway, would it?

[WGB]

Sounds more like driveline or spark/fuel problems andrew.

No a timing chain would never cause a vibration unless it was a big one.

Bill

[CraigS]

Unlikely, until it was about to suffer a total hemorrage. More likey to be as Koan suggested and be valve timing i.e. the engine pinging, which you would hear inside the cabin under acceleration. As WGB suggested, this could be caused by the timing being out.
If the flex disk is on it's way out, you would be more likely to notice a vibration at speed, irrespective of whether hot or cold.

Is it ever possible, do you think, to hear it during acceleration or just cruising?

[Andrew280SEL]

Thanks guys.

I'm not 100% sure it's just when it's cold, I'll have to really pay close attention next time I drive and see what I can work out. 

[koan]

More likey to be as Koan suggested and be valve timing i.e. the engine pinging, which you would hear inside the cabin under acceleration.

Not quite what I was suggesting. Later 116  engines are fitted with hydraulic lash adjusters that do away with periodic valve clearance adjustments.

The hydraulic adjusters have an internal valve that keeps them filled with oil.

If the engine happens to stop in a position where a leaking adjuster is under pressure from a cam lobe and rocker arm (valve open) that adjuster gets the oil squeezed out of it. When the engine is started next time the cam hitting the rocker makes a hell of racket until the adjuster fills with oil again.

It doesn't always happen because the engine doesn't always stop at the same position.

Edit :  Don't know how managed to post the following quoted bits without any new text,
can someone please remove it.

koan

[koan]

Unlikely, until it was about to suffer a total hemorrage. More likey to be as Koan suggested and be valve timing i.e. the engine pinging, which you would hear inside the cabin under acceleration. As WGB suggested, this could be caused by the timing being out.
If the flex disk is on it's way out, you would be more likely to notice a vibration at speed, irrespective of whether hot or cold.

Is it ever possible, do you think, to hear it during acceleration or just cruising?