Timing Chain Hell!!!!!!!

[190easy]

please help i bought a w201 190e 2.0 (93k) with 100k on the clock and a snapped duplex chain i've since had a replacement engine installed only to find the alloy head was corroded and had to be removed, alloy-welded, skimmed and re-fitted now, 2wks later the camshaft breaks and almost snaps the duplex chain my local mb specialist reckons the chain tensioner is non-hydraulic and was over tensioned, the garage who fitted the head say the tensioner is part hydraulic-part spring operated and cannot possibly be fitted incorrectly, personally i think they've cocked up and are reluctant to admit but if any one can forward info on the tensioner or has any advice i'd be glad to hear it thanks.........:cry: also since the head was re-fitted its been almost impossible to start when warm?????

 

[mike65]

In my expierence you can't really fit a tensioner badly, the thing is a simple spring loaded yoke that screws in under great pressure, once its in and tightened correctly that should be that.

In this diagram 134 is the tenioner assembly.

 

[tom7035]

A very important point when working on the tensioner assembly is on no account begin the job, have it half-way undone then change your mind and screw it in again. This grossly overtensions the chain with the result you have experienced.
Once you start unscrewing it you MUST remove it completely before re-installing. However, if you're replacing it completely it shouldn't be a problem. I think you're right, the garage 'cocked up'.

 

[television]

I think it depends on where the camshaft has broken, Has it sheared off where the sprocket bolts on, or is the break somewhere else

Malcolm

 

[turnipsock]

the garage who fitted the head say the tensioner is part hydraulic-part spring operated

eh? I'm not sure about the hydralic aspect, if the camshaft timing is dependant on the oil pressure, I can see a few problems looming.

...anyway, surely if you had the cover off you would at least check the tension of the chain, with your finger, before puting on the cover?

 

[stunW210]

please help i bought a w201 190e 2.0 (93k) with 100k on the clock and a snapped duplex chain i've since had a replacement engine installed only to find the alloy head was corroded and had to be removed, alloy-welded, skimmed and re-fitted now, 2wks later the camshaft breaks and almost snaps the duplex chain my local mb specialist reckons the chain tensioner is non-hydraulic and was over tensioned, the garage who fitted the head say the tensioner is part hydraulic-part spring operated and cannot possibly be fitted incorrectly, personally i think they've cocked up and are reluctant to admit but if any one can forward info on the tensioner or has any advice i'd be glad to hear it thanks.........:cry: also since the head was re-fitted its been almost impossible to start when warm?????

Don't know if this will help you but I worked for Renold chain for a few years, they make timing chain systems for manufacturers. They developed a timing chain system for GM to guarantee 250,000 miles per chain for 'sealed for life' engines. Renold received an order for $10 million in return. Every Porsche now runs Renold timing systems, all guaranteed to run in exces of 200,000 miles! Renold have a factory in Calais making only automotive systems. You must be sure that any chain is quality, off the shelf chain can be very poor, make sure the wheels(sprockets0 are new and the guides are good! If I can help let me know,god luck.

 

[190easy]

sheared right off at the end at the sprocket!

 

[TimN]

Is it possible that thew cam journal was not being fed with oil?

 

[television]

If the camshaft sheared at the cam end it would sugest that the garage that fitted the chain, set the guide rails incorrect, thus over tightening the chain.

Malcolm

 

[bundy]

there is no adjustment on the rails on this engine. the chain may have been tensiond incorrectly if the mechanic is not familiar with this type of tensioner.
the tensioner body must be screwed into the block first followed by the hydraulic assisted piston followed by the pretension spring,washer & end cap.
afte first ensuring the chain slack is on the tensioner side. if the tensioner is refitted as a complete assembled unit it will over tension because the tensioner has a one way rachet inbuilt. the only guide rail that moves is the tension side slipper.
regards ted

 

[television]

I understand on these engines that the tensioner is not the conventional ratchet type.

malcolm

 

[flagstaff]

not sure about that, Malcolm: i've fitted a tcc to one of these engines and it /was/ the ratchet type. as per other posters' comments, the correct install procedure is absolutely vital or the chain will be overtensioned. the body goes in first, and then the central cylinder. it very often needs a sharp tap to get it into the ratchet, after which it cannot be withdrawn without removing the entire assembly.

 

[bundy]

I understand on these engines that the tensioner is not the conventional ratchet type.

malcolm

trust me iv,e rebuilt so many m102 engines that i can do them in my sleep

 

[television]

trust me iv,e rebuilt so many m102 engines that i can do them in my sleep

I do trust and take note of what you say, so thank you. it just upsets me when a garage can do this to someone, and then deny it.

malcolm

 

[bundy]

hey malc not all traders ( garages ) are honest. but neither are most trades.theres always good & bad.its just a case of if you think your getting ripped off you probably are. caveat emptor. NIL TAURUS EXCRETA spoken here!!
regards ted