C class 200k cam chain gone at 100,000 miles

[WG M-B]

And check those pistons aren't damaged....

 

[zenman63]

The pistons look fine, some small polished areas in the eyebrows but thats it.
The cylinders look very good and the cams all good, nice and clean smooth surface.
No lips on the bores.
Why the valve guides? the valve slides very easy, there not damaged in any way.
The valves all bent on the top.
What about the crank sprocket?
This car has full history and fully synthetic oil.

 

[zenman63]

 

[gazz]

Wayne mentions the valve guides because they can become "tweaked" at the lower edge by the bent valve. This can lead to the replacement valve failing to rotate during engine operation. This prevents "seat cleaning" and can result in a burned valve or seat later on.
The man knows his onions.

 

[zenman63]

I am sure he does and thanks, the new valves spin free in the guide, no friction of high points.
The gears are my issue, I understand now the crank sprocket is steel, but the cam sprockets are £449 each!

 

[zenman63]

Almost forgot, £1449 in parts, no labour as I am a home mechanic!
Head gasket is cheap enough @£28 and the valves £12 each.

 

[gazz]

Yes, the pricing is a bit of a joke, especially as they obviously have a material defect in many people's eyes!

 

[zenman63]

Yes, the pricing is a bit of a joke, especially as they obviously have a material defect in many people's eyes!

Your not kidding, but anyone with this M271 engine must change the chain early as they will all be the same.

Whats the best case gasket these days?

 

[zenman63]

Progress

I spent most of the day Saturday cleaning parts and removing the oil varnish.
Valves all re ground, I went for genuine ones at £12 each
And head gasket at £28.
Cam chain is after market and followers are new and genuine.
Around 12 hours into it now.

 

[jaymanek]

im sure mercedes used to have a telly ad ending with the quote meticulous engineering ???

These aren't mercedes engines they are Mitsubishi... Blame the accountants...

Can't wait for all the problems with the Renault engines now being used...

 

[ricardo62]

These aren't mercedes engines they are Mitsubishi... Blame the accountants...

Can't wait for all the problems with the Renault engines now being used...

I thought the reason mercedes cars are so much more expensive than other makes is because of the engineering and german quality?ie back in the yr 2000 a e320 would of cost around 54000 pounds ,compared to a mondeo at £18000

 

[markjay]

Slight hijack, interesting discussion here re the origins on the M271, no firm conclusions though:

http://www.mbworld.org/forums/showthread.php?t=338136

 

[zenman63]

It has mercedes stamped all over, even the valves have Mercedes stamps on them.
It might have been a joint design but it's a Mercedes engine.

No hijack please keep it coming.

 

[jaymanek]

The parts will have mb logos, but it's not an mb designed engine.

Think of mb sprinter van and the VW equivalent.. Same design and each part has their own part numbers even though most parts are interchangeable ..

Anyone who has worked on a real mb designed engine such as a 119 or 113 or 104 etc will know that this is not mb,s design as soon as they take a spanner to this... It's from the times of Daimler and quality issues..

 

[rorf]

Zenman you mentioned that the engine had a timing chain rattle for some time before it jumped a few teeth - this would surely indicate a problem with the hydraulic tensioner.

Please measure the length of the new chain against the old one to see if in fact it has stretched, if this is the case then these Mercedes engineers should be fired as this was a problem with every engine before that had a single chain:fail

 

[markjay]

...if this is the case then these Mercedes engineers should be fired as this was a problem with every engine before that had a single chain:fail

...And those who designed the rusty wheel bolts should be sent to the Tower... 10 years on, and they still didin't fix it. New bolts bought today still rust. Go figure.

It is odd how some issues just became 'a known problem' and no attempt is made to rectify them.

 

[zenman63]

Zenman you mentioned that the engine had a timing chain rattle for some time before it jumped a few teeth - this would surely indicate a problem with the hydraulic tensioner.

Please measure the length of the new chain against the old one to see if in fact it has stretched, if this is the case then these Mercedes engineers should be fired as this was a problem with every engine before that had a single chain:fail

Yes the chain was one full link stretched.
New cam gears on the way and will post some pictures.

 

[nb_racing]

What state was the tensioner in? Did the chain break because the tensionner failed; or did the chain snap of its own accord? either way I'd be replacing the tensioner.

 

[zenman63]

The gears were worn, and the tensioner and the chain had stretched, its all new and I re built the head with new valves.
The sprockets from M271.co.uk are first class and I have them on, the chain is a mission to get 100% and will look at that again before I move on.

 

[zenman63]

What state was the tensioner in? Did the chain break because the tensionner failed; or did the chain snap of its own accord? either way I'd be replacing the tensioner.

The chain had jumped a good quarter on the inlet side, it was so worn its a wonder it ran at all.
You could put a spanner on the cam and move it, slipping teeth.