Replacing the chain (single link) which tool is needed

[Marco]

I please ask if you can address/suggest for this basic job that nowadays mechanics seem they don’t have anymore the tool
Cutting the chain I think is easy in the worst case with a grinding machine …even if horrible only to say …. but is there any tool I can buy assuming the mechanic will not find? And I don’t like the idea to hammer the link …
I have at home the parts but now I can just post the pictures from internet but is the same

Thanks to address me
Best
Marco

[shaq]

Hi Marco,

You are completely right, even if 99% of mechanic will hammer the link ends to keep it secure. And in praxis it will work for long time as chain doesn´t receive axial forces in principle, forces are mainly longitudinal and chain slowly gets longer from it and than snaps because of sprocket teeth distance dont match anymore to lenght of individual segments of the chain. So high mechanical stretching force breaks the chain, very rarely sprocket teeth fells off as it is like 10x stronger then chain segment.

Similar story to bicycle or motorcycle chains and sprokets, only here sprokets dont get wear easily (swimming in lot of oil) unlike on bicycles/motorcycles where chain is always to be exchanged together with worn sprokets as it is much thinner and of softer material made.

Getting longer and having not matching link lenghts to sprocket teeth is the reason it breaks after long use. I know of cases driving one chain near 200.000kms still hold and only than breaks after jerk drive style - so on 70.000 change intervals you dont need to worry at all. Even Evo2 has single chain. It is more responsive desing than double chain and all is OK as long as car is maintained properly and of course with quality parts.

In my opinion you are completely right, if hammered to make it expand into place, that one link and two sorrounding get damage and this is the place that can break later on sooner than other parts of same chain.

From Mercedes there is official tool (number is printed in WIS) which you put chain inside and get exactly pressed like chain is made one piece from factory.

It is delivered to each official workshop as suitcase of different ends for the tool, even if my local dealer in my hometown lost most of it so I took my chain to Germany to Mercedes to have it properly mounted (crazy)

But back then my engine was overhauled, disassemlbed into parts - so not a big deal. BUT it would of be a big deal on closed motor like yours.

To give you idea how the tool looks (but much more massive) is this eBay tool for bicycles.

Bicycle Chain Tool eBay

Problem for bicycle tool is not maybe too small force of screw for pressing - but the fact that length of segments tool is intended to must accurately match the chain. Chain can not be closed if its segments dont fit (lay down) perfectly down in the tool (there are black teeth to hold chain longitudinal in place then it get pressed from the side - study carefully the pictures in the link)

PS I looked again and found something that looks like MB Dealers tool:

Car Chain Tool

Bye, N.

[Marco]

Ciao Nikola
Thanks for yours always valuable intervention, yes we are on the same page, meanwhile I had found the Mercedes tool part number and some products available that copy this design, like your last link.
It’s worth to note that same tool is still used, I’d say common, for recent Mercedes diesel engines.
I’ve managed that one mechanic with the tool will pass to the garage I’ll do the job I also found and read the procedure how to proceed, it’s a 10 minute job for someone that do this regularly…or better that was used to do this regularly 30 years ago and more
Comparing single vs double chain it’s amazing how robust the second is compared with the bicycle style I have, but it’s very good that inside Febi box there is this very good Iwis brand.
Double chain looks like they can last for millions of kilometres but probably they are over designed to the point to be too rigid and other problems may happen if you don’t check regularly, you mentioned already something with the tensioner.
I know many earlier 2.3-16 had issues with broken engines because of chain, do you know which was the fault? I know the tensioner replace but I’d say that was purely for the very first moment of the engine on when tensioner without spring had not built up pressure to push the chain rail, was only this the problem?
Wish a nice weekend
Marco

[shaq]

Hi Marco,

As to information I have, 2.3 16 single chain is not design problem, if maintained properly it lasts, if driven 200.000 is dangerous of course.

Even 40 years later i know many Mercedes or BMW designs that use single chain in 2010 - 2015 models.

Again double chain has disadvantages - harder to tenison, engine looses reponisvity, looses some HP on internal friction etc.

There is no perfect solution. For Mercedes 16v engines of w201 family was just experiment and learning curve for 4 valve engine technology for the Future.

Those chains were too long and wrong by design. But it was early 1980s and Mercedes never believed in toothed belts like Ford Coswort or Opel.

Chains.png

Modern design of similar 16v engines is short chain going from crankshaft only around one camshaft (lets say intake) and going back - the other one is moved using gearing mechanism not chain

Again all these chains to make problem only when too long. When still new even if tensioner hasn´t built pressure during start everything will be OK since chain PERFECTLY FITS GAPS IN SPROCKETS like hand and gloves - but once too long than it makes damage, on 2.3 16 chain will break, on Evo2 theoretically too (but Evos are much more taken care because expensive) , on 2.5 16 double chain will not break but it will jump breaking valve cover in its area or break intake camshaft at least one case is known to me where this happened.

Ciao
Nikola.

[Marco]

Hi Nikola
Yes I see the point, from previous recommendations you come here to the conclusion that single chain last 70-80000km, or better to say, is worth to replace at these intervals.
I know that earlier 2.3-16 but also normal 8v suffered from chain breaking solved by Mercedes with subsequent modifications, from my reading I found that there was a modification in the chain link where pin connect the links with a sort of notch that permit oli to be better in contact between the links, probably it was a problem of not enough lubrifications of the chains.
By the way yes these are really long chain and yes for EVO2 reactivity they had to return to single chain but I think is quite evident that the impressive double chain of 2.5-16 was the tentative to remedy to some problems they had with singe chain.
I think also that BMW with E30 M30 was not different with the timing chain configurations still a long path passing both cam sprockets but I never heard of problems like early 2.3-16.
Can wait to have my new single chain installed
Buona domenica
Marco

[shaq]

Hi Marco,

I don´t like BMW at all and don´t believe their design was better.

It may be the case that they were only better maintained (or they had service interval prescribed from Factory when to replace the chain - where older 190e 2.0 with single chain or 2.3 16 has nothing of that)

our 70.000km is Forum experience, not recommendation from Mercedes

even old BMWs had oil interval LEDs to remind owners and Mercedes was thinking their products will come to official service points who will take good care maintaining the car altough many were serviced by private workshops with very little knowledge or zero knowledge of 16v specifics. Even your garage told you chain is good, it is still silent...

If we speak Evo2 single chain with far more stress than 2.3 16 and don´t have known chain problems - it has far more force (better to say chain stress) to cope with than 2.3 16v (longer valve travel, double springs for each of 16 valves, more RPMs) but owners maintained them better and they work excellent.

I think problem that 2.3-16s was its low price at some point of 90 - 2000s (price was never low for Evos or M3s) at some time they were sold as low as 1000 - 1500 euros, the bad examples, and then driven to red line by boy racers until something fells off.

Now 16vs are became enthusiast cars and second or third or fourth car in the house, making maximum few thousand km pro year so once exchanged it is like forever done job!

Bye,
Nikola.

[Marco]

Hi Nikola

Funny you don’t like BMW at all yes the famous led lights for the service intervals who knows if they are still present in the recent cockpit. But probably long chain layout was very similar also on E30 M3 and their engineers did not repeat the error. I had the M5 E34 many many years ago, I did not go deep as I’m now with our sweet 16 but I remember head gasket blown with nice emulsion of oil in the coolant reservoir.

Yes I understood perfectly that the 70.000km is Forum experience, not recommendation from Mercedes, and for sure experience counts much more, hence my fully trust on you and my decision. Is well known that boy racers bought for nothing till destruction most of 2.3 and 2.5 probably, as these cars never had same interest of M3, now is better but still 1/3 if not less the market values.
But I was wondering the scenario in the ‘80 who knows these disasters at what kilometres did they appear…

Have a great continuation of the week
Marco

[Marco]

Hi Nikola

I hope you can revert quickly tomorrow morning …today … we finish the job.
Chain replaced and with the proper tool.
I’ve just a concern, on the chain tensioner, see picture
I would have wanted to open to replace the spring.. they were too quick to pay attention and they dismounted the whole piece…said this is the last and correct type of tensioner working mainly with oil pressure (!?) ….unless this is the ratchet type that absolutely requires to be dismounted to reset the spring this is not a problem I hope… am I correct?

The second point: I wanted to replace the alluminium sealing ring, I bought all dimensions from catalog parts, but this turn out has an o-ring, this is totally out of what I expected and did not see a replacement code for the o-ring and was installed back the same …is it useful an outside turn of liquid black seal ? I totally hate oil seep…


Thanks

[shaq]

Hi Marco,

I was away for few days, I thank you bringing our Forum back to life, it was sometime months without a single new posts here. So I am used to come when I have time rather than every day.

Dont worry like I said if it is ratched type than it is very dangerous to install it assembled.

If it is not ratchet type but oil pressure only - that sprng is strong, but can you with force of your fingers push the middle pin back or not at all?

Because I think it is not ratchet type and you suspect it is. Ratchet also work on oil pressure but not on oil pressure ONLY, OK?

It is the only way to proof - ratchet type you can never push back even 0,001 mm and oil pressure type piston or pin can be pushed back (the pin pushed towards inside of housing from the point where it touches chain guide)

About your picture if it is using O-ring (rubber) and no metal ring, it is strange to me, I never saw 16v tensioner not using aluminum ring. Is it original like that with O ring in you case or someone installed it by mistake?

O rings you can buy a set for small money (every good workshop should have them) so dont look for part numbers select o ring from the sizes you have in box.

O rings set for Workshop


Bye
Nikola.

[Marco]

Hello Nikola

indeed you reverted quick was it just a coincidence?

I'm happy to contribute to Forum wellbeing, sometimes just the minimum helps to avoid oblivion all seems works on socials today...

I was saying since the beginning that externally the tensioner is totally different to usual pictures I see in internet, I searched also here in the forum but most of the discussions have dead link for pictures...but to answer your points this is what I can say:
- agree nothing like other tensioner I have seen
- agree nothing I've seen has an o-ring, indeed I had all the size of available aluminium seals but useless here
- Mercedes mechanic confirmed it's original and the most recent type (assuming as I take that the most recent is not the ratchet type for 2.3 16 with original single chain)
- I don't have reason to think someone removed to put a third part component, I have found only original parts on this car (but now not anymore because when I put hands often the part is not anymore available in Mercedes and I nd with Febi, Corteco etc
- I'm chaning now the chain for the fist time
- is not ratchet type, I can push back the pin, it offer a good resistance but it move in and immediately out when released

final considerations to the above: regardless it is original or not it is not ratched type, was it a problem "he" did not remove th inner part and after the outer parts? he removed and installed all together. If I understand well, even if the proper procedure is to take internal part and then the outer housing, I can't see any drawback on this, in other words there is nothing to reset internally the tensioner.

funny (not really) they made the an error, this happen when you are too good and want to be quick...they messed with the chain links and the exhause cam sprocket was out of phase by one chain link......indle was a nightmer...by the way this was the chance to put fresh o-ring despite redo half parto of the job and I hate to slacken and tighten spark plug, cables, belt, belt tensioner etc...I prefer to take double of time and do by myself...when I can.

see picture of the old chain and cams and new chain with correct phase...

oh yes I forgot, valve clearance was ok, not really cold but not super hot engine: exhaust 0,30 all valves, intake 0,20 five valves, 0,18 two valves and 0,13 one valve.

thansk once more for assistance!

best
Marco

[shaq]

Hi Marco,

As it is not ratched type it is normal to install it as a complete part. That spring is only used in first two seconds after engine start until oil pressure in engine is reached.

After that oil pressure takes the control pushing tensioner pin out to press chain rails much harder than any spring can do. Because it is hydraulic force

Yes I agree, at 2.3 16 final design was not ratchet type. I think out of 3 versions ratchet type was 2nd version and then for 3rd version they stayed with oil pressure (maybe modification in inner valve to push chain harder - who knows).

PS Your chain sprockets are still very good. When heavily used they look like triangle and your still look like brand new. Very good picture.

PS2 Valve clearance is much more important at exhaust side, because there thermal expansion happens. For intake side much less important, because on inlet side if they are to tight and dont close properly (can almost never happen but letş speak theoretically) nothing will happen to valves, maybe you will loose little of compression thats all.

BUT on exhaust side if they are to tight and not closing properly on hot engine, valve will burn, valve seat will burn and you need expensive repair because of nothing. So on exhaust side is always better to keep valve tolerance gap close to maximum, NEVER close to minimum or below. So 0,30 is perfekt IMO

PS3 someone missed exhaust sprocket by one chain link that's hardcore man, you could easily end with major engine damage. Maybe you were lucky they shifted it the way when piston is in opposite direction from valve, otherwise it would hammer each other and break. That is a big NO for those mechanics.

Bye
Nikola

[Marco]

Hi Nikola

We just remain with this not seen before tensioner with oring gasket instead of alluminium seal for the rest thanks confirming it’s fine to dismount it as one piece being a not ratchet type. After the mistake of the one link skipped I was much concerned about other stupid errors …

Yes I had well in mind to be focused on exhaust valves gap to be better in the upper range of tolerances as we discussed it tends to became tight … when it would appeared to me the opposite… more km more gap but it is not

Yes all three mechanics looking to this job said these engines, not my own, are very good piece of machined state of art, and nowadays engines are ruined when they open… but who is repairing engine now? People change car way before it need a rebuilt because there is a bigger touch screen available in the center console

This potential damage because they did a stupid thing (skipped one link) hope that if it happened it would have destroyed immediately and now I can leave relaxed after this potential nightmare…
Chain is tighter than old one and feel engine a little more reactive may be is only impression

Have a nice evening
Marco