Author Topic: 450 - M117 Timing Chain Replacement  (Read 72261 times)

WGB

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450 - M117 Timing Chain Replacement
« on: 20 April 2007, 08:15 AM »
The archilles heel of the M116 and M117 motor is the timing chain and many a good car will die an early death if the timing chain is not changed every 100,000 miles and particularly in conjuction with the plastic sliders and hydraulic tensioner with it's own plastic slider (Liner). It was also recommended that I change the camshaft sprockets as well as this would assist in getting the cam timing nearer correct.

First job was to secure the parts and this is what was purchased along with some new Cam cover gaskets, a new auxillary air valve and a new fuel filter.




The air-cleaner, Sparkplugs,fan, Battery and battery holder, and radiator were removed and a bag was placed over the throttle body to stop any stray parts dropping into the engine.

The engine was turned clockwise (looking from the front of the car) on the crankshaft nut to TDC - never go backwards at all and if necessary only 1 or 2 degrees to make something fit



Next all the ancillaries including belts, pulleys, alternator, distributor and power steering were unbolted and removed. The position of the distributor at TDC was marked to make a good starting point for the timing at reassembly.

The power steering pump and reservoir were left connected to the pipework and tied to the side of the engine bay so as to spill as little oil as possible.



The camcovers were removed and on my car (with 168,000 recorded miles) the sprockets and sliders were original but the chain had been replaced at some time as it had a joining master link vbisible.

The chain stretch is measured by aligning the RH camshaft timing marks by rotating the motor with the crankchaft pulley nut (Clockwise only) using a socket, short extension and a large ratcheting torque wrench which I own.



Here is a view of Right Hand Cam timing marks  - in alignment



At the same time here is the Left hand cam alignment marks showing that the chain has stretched and that the sprockets are worn as the marks do not align.



Again at the same time the crankshaft is reading 10 degrees after TDC - maximum chain stretch is 11 degrees ATDC on a 117 motor.



The next step is to change all the sliders, cogs and tensioner with it's slider before the old chain is touched.

The sprockets and sliders can be removed without splitting the chain by removing the tensioner and giving sufficient slack for the sprockets to be removed.

They will need to be removed (One side at a time)  to give enough clearance to remove and replace the sliders.

Here is a view of a new white coloured slider sitting on top of the chain to show the contrast with the old very dark brown slider in it's correct position



Here is a new slider and cog alongside an old slider and cog. There is a spark plug socket with a bolt through it which has been used as an extractor to remove a slider pin.

The pins (2 per slider) are held into the heads by friction only and are internally threaded to allow a bolt to be threaded into them for extraction. The factory method is to use a slide hammer on these attached bolts. The non-factory method is to use a nut on the thread of the correct sized bolt working against packing which is placed between nut and head material or if there is room the bolt is pulled through a spark plug spanner.
The pins are very tight and the surface of the head is not smooth so patience and different types of packing are used to get a straight pull



The left hand head has ribs on the front and here I have used an open ended spanner to keep the packing straight and am using the nut as the means of leverage.

To replace the sliders you will have to remove the sprockets whether you change them or not, just to give adequate clearance for removal and replacement of the slider pieces. You should use cable ties to hold the chain in position on the sprockets, then unbolt the sprockets while using a screwdriver through the sprocket hole to steady it and then keep the chain in tension so that it cannot move on the crankshaft sprocket .

The sliders are replaced and the pins driven back in with a bolt screwed into the end and gentle taps with a hammer.

The old tensioner is removed by removing the two bolts that locate it.

To remove the tensioner slider the lower pivot point has to be released. It is housed inside a cap low on the front of the motor. The cap is unscrewed and inside is a hollow pin which can be extracted by slipping a phillips head screwdriver into it and jiggling the tensioner arm and the screwdriver until it appears - may be worth tying a piece of wire to  the top of the slipper so that it doesn't drop too far but from memory it can't drop right down.

The plastic lining of the tensioner slider is replaced by unclipping the old liner and clipping on a new one - locating lugs are moulded into the ends of the plastic liner.

While the tension is off the chain I replaced the Camshaft sprockets with new ones taking care to keep the teeth and keyway position in alignment.

The new tensioner was filled with oil and screwed in to keep the old chain in tension.

At this point the old chain was clamped to the RH sprocket with cable ties and the master link divided . I used newspaper to stop anything dropping into the motor. If there is an original chain with no master link a link must have it's peened ends ground off with a small grinder like a Dremel to enable it to be joined with the new chain.



Here is the old cable joined to the new cable. The method calls for large re-usable cable ties but I didn't have any so I used a large packet of non-reusable ones and cut them when they needed to be removed. I found I needed two per time to stop the chain from slipping on the sprockets - next time I would use Vise-Grips with tape or plastic pipe on the jaws.



Here the new chain is being fed from the box sitting at the side of the engine bay while the old chain just continues to fall to the ground down the side of the motor with the crankshaft bolt being slowly turned clockwise.



Here is the new master link with the new more robust tiny C-clamps - it's a real art to get these on without dropping anything - I again filled the space below with newspaper in case I dropped anything and had magnets on standby.



This shows the completed right hand cam tower with new chain, sprocket, slider, tensioner and tensioner slider all visible. Also visible are new plastic oiler fittings attached to the steel lines that run above the camshafts and lubricate them - mandatory replacement for only a few dollars more.



And here is the completed job - just needs the ancillaries and radiator put back again.

The engine was quite different after the chain replacement - a lot of extra horsepower came from getting the timing right - total cost about $600 - 2 years ago. (original parts from Main agent were quoted at about $2300).

Please do this to your own 3.5 and 4.5 motors before they expire.

6.9 motors apparently have a ratcheting chain tensioner and are not prone to the same risk of instant and unannounced disaster as the smaller motors.


Bill



« Last Edit: 20 July 2011, 05:30 PM by WGB »

oscar

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Re: 450 - M117 Timing Chain Replacement
« Reply #1 on: 21 April 2007, 09:44 AM »
Bill,

This is a fantastic post.  I meant to say so the other day but this kind of info is what this place is all about.  If only I saw this and some other posts regarding this job earlier, I could have saved myself some labour costs.

When my mechanic first mentioned my chain was stretched and he wanted to change it, I said ok.  Why not.  The rocker covers were off and he showed me the chain saying that it was worn.  I couldn't tell, it looked exactly like yours.  But it made a difference and there's peace of mind knowing how old the chain and slides are now.

Were you going to replace the oil tube parts as well?
1973 350SE, my first & fave

Tomi

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Re: 450 - M117 Timing Chain Replacement
« Reply #2 on: 21 April 2007, 11:24 AM »
great post and good pics.
its always so terrifying to drop something in that hells pit and this makes all these precautions to be good practice.
It seems that the old chain is not the original as it has the link (the original was endless) this is a good sign for that the links do actually work. This is an endless debate on how to securely connect the chain together. some say that the only way is to stamp it. well, I guess the link works but it should be directed so that the open end is opposite the chain movement direction.

Another question is that after installing a new chain do all the 3 marks align. In my case the right cam was a bit off or before. i think this could be caused of the chain not being stretched enough initially, but in time it should align better.
MB 450 SEL -80 (oldtimer for the class)
MB E220T -95 (daily driver)
MB 230E -82 (a present for my son)

WGB

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Re: 450 - M117 Timing Chain Replacement
« Reply #3 on: 21 April 2007, 06:27 PM »
Hi Oscar,

I did replace the plastic oil connecters as well - they are in two packets in the centre of the first photo and I think only cost about $10 to $20 although there seemed to be no real brittleness in the originals.

Hi Tomi,

No the three timing marks didn't quite match up at the end - I can't remember but I think it ended up about 2-3 degrees ATDC at the finish.

It would have required replacement of the crankshaft sprocket to get it all back in alignment completely and at this stage it was not part of the agenda. The engine ran much more smoothly after this change and seemed to pick up a lot of horsepower.

Bill

oscar

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Re: 450 - M117 Timing Chain Replacement
« Reply #4 on: 21 April 2007, 06:49 PM »
Hi Oscar,

I did replace the plastic oil connecters as well - they are in two packets in the centre of the first photo and I think only cost about $10 to $20 although there seemed to be no real brittleness in the originals.


Ahh so they are. Pays to look in detail  ;D  I thought they were white when new, hence I didn't notice them (let alone read the picture tags)



Hi Tomi,

No the three timing marks didn't quite match up at the end - I can't remember but I think it ended up about 2-3 degrees ATDC at the finish.

It would have required replacement of the crankshaft sprocket to get it all back in alignment completely and at this stage it was not part of the agenda. The engine ran much more smoothly after this change and seemed to pick up a lot of horsepower.

What about offset woodruff keys?  I remember seeing them at autohausaz.   I doubt you'll try now since you've got it all going again but theoretically, if you were to take the covers off again and replace a chain down the track, could these help?
http://www.autohausaz.com/search/product.aspx?sid=3ojvm545ses5lb55qzzyh145&makeid=800016@Mercedes&modelid=1194847@450SEL&year=1978&cid=20@Engine%20Parts,%20Seals%20%26%20Gaskets&gid=5519@Woodruff%20Key



EDIT:  Another question WGB   -   Did you by chance pull apart the old chain tensioner?   Any chance of having a look of what's inside and how has it worn?  Is it just the tip that's worn down or is there a spring inside that has weakened or did you replace it for peace of mind? 
Cheers
« Last Edit: 21 April 2007, 07:33 PM by oscar »
1973 350SE, my first & fave

WGB

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Re: 450 - M117 Timing Chain Replacement
« Reply #5 on: 21 April 2007, 09:47 PM »

Good Point Oscar,

I have seen the offset woodruff keys in a Chilton's manual and in the Handbook I think.

If I ever pass that way again I'll measure and think about it - wouldn't be hard to put them in, even now.

I don't know how much difference 1 or 2 degrees make - certainly 10 degrees makes a big difference.

I still have the old tensioner and will pull it apart at some stage and see if I can see what is worn.

I didn't even consider doing the job without replacing the tensioner so didn't pay much attention to it other than there is a difference betwen the Euro tensioner and the Australian one (Extra pipe fitting for some reason on the Ozzie one).

Certainly the new one took a lot more effort to compress than the old one.

Bill

« Last Edit: 21 April 2007, 11:49 PM by WGB »

oscar

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Re: 450 - M117 Timing Chain Replacement
« Reply #6 on: 21 April 2007, 10:24 PM »
I didn't even consider doing the job without replacing the tensioner so didn't pay much attention to it other than there is a difference betwen the Euro tensioner and the Asutralian one (Extra pipe fitting for some reason on the Ozzie one). Certainly the new one took a lot more effort to compress the new one rather than the old one.

Something else I noted whilst looking for pics was two types of tensioners, with and without smog stuff attachment. That's what the extra pipe connection is for.  Compare these two shots from http://www.mercedes-benz-parts-direct.com/epc-items.asp

Anyway, it's good to know the different feel and strength of the new tensioner compared to the old one.  Something I've learnt from your posts is regarding when the chain breaks or guides shatter.  I always thought it happened at speed but your descriptions of what the chain does on startup  has me believing the opposite now.  It's been stated by yourself and others about the vulnerability of the chain and guides upon starting.


1973 350SE, my first & fave

WGB

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Re: 450 - M117 Timing Chain Replacement
« Reply #7 on: 21 April 2007, 11:31 PM »
I don't think the problem occurs at high speed as the tensioner should be under oil pressure no matter how worn it is.

I have seen postings in the forum atwww.mercedesshop.com of peoples experiences with chains and they all talk about startup or startup and manouvreing in their own driveway at low speed. The engine suddenly stops with a bang and on opening the bonnet the camshaft towers have broken through the camcovers when valves have kissed pistons. It's almost like the cam towers are like fuses and let go to save more expensive damage to pistons, rods and crankshafts.

The sliders and chain are always blamed but I think the chain thrashing around with a loose tensioner sounds more realistic .Then when a brittle slider breaks it can get caught between chain and sprocket and cause the chain to jump.

My sliders were very old and the full chocolate colour which is what they become when due for a change but they were not deeply grooved nor overly brittle.

What was brittle was the plastic insert lining the guide attached to the chain tensioner. This is a light grey/green colour and can be seen in the photograph of the parts with the part No 117 052 00 83 written in texta on the surface.

This is an interference fit on the metal guide with lugs in the plastic that snap and hold it into place - the one in my car was almost black and broke up into a number of small pieces when I tried to remove it.

Bill

SELfor50

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Re: 450 - M117 Timing Chain Replacement
« Reply #8 on: 22 April 2007, 03:37 PM »
Hey Mate,

i did have a look at this post over the weekend - just didn't have time to reply as had to help a mate move house.

You're TRUE BLUE!!
This is possibly one of the best pieces of advice i've ever seen on the internet!!!
I haven't done much work on cars, but with the right prep work i'm gonna give this ago. 
I'm ordering the parts this week and will hopefully get it done next weekend.

Other than the step by step guides and tips here - is there any other major things that i should know before doing this??

"Man who come first, wins race." -Unknown

-= 1978 - 450 SEL [Euro] =-  Locked
-= 1976 - 450 SE 6.9 #2 =-  New Heart

WGB

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Re: 450 - M117 Timing Chain Replacement
« Reply #9 on: 22 April 2007, 05:52 PM »
Hi SELfor50,

Have a go and take some photos and share them with us.

Just don't drop any bits into the motor and make sure you pull a couple of rotations through cleanly on the crankshaft bolt when you're finished before starting her up.

The hard bits are pulling the pins on the sliders and then pulling the new chain through slowly.

If you want to see a much better pictorial spend US$24.95 and go towww.pindelski.com - he has a step by step photographic run through with explanation, of changing the sliders and then pulling through the chain - but you have to buy a subscription and it is a 126 site.

He changes a 560 chain but it is exactly the same.

If you want any advice put it on the site but I will be away for a few days with my wife from Thursday til Monday and internet reception may be patchy and marginal - depends whether my new NextG card will arrive before I leave with ANZAC Day and all.

My E-mail is on the site and if you want to send me a message I'm happy and it may be more likely to reach me.

Best of luck and go slow and careful.

Bill

SELfor50

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Re: 450 - M117 Timing Chain Replacement
« Reply #10 on: 22 April 2007, 11:11 PM »
Word, and Word.

I'll post the photo's when i'm done.

Cheers Mate!

"Man who come first, wins race." -Unknown

-= 1978 - 450 SEL [Euro] =-  Locked
-= 1976 - 450 SE 6.9 #2 =-  New Heart

s class

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Re: 450 - M117 Timing Chain Replacement
« Reply #11 on: 24 April 2007, 01:51 AM »
Excellent work Bill.  Thanks for taking the time to share this with us. 

I see you replaced 3 guides plus the tensioner rail lining, all at the top of the engine.  Are there not other guides at the bottom of the motor?  I presume though they might be difficult to get to without removing the timing cover. 

What brand of chain did you use - you said not MB dealer.  Does anyone have thoughts on aftermarket chains?  I need to do this in my 450SL.  I am so worried about the state of my chain et al that I haven't been driving the car.

Ryan

'76 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '82 500SEL euro full hydro, '83 500SEL euro full hydro , '81 500SL

WGB

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Re: 450 - M117 Timing Chain Replacement
« Reply #12 on: 24 April 2007, 02:36 AM »
The chain is an JWIS which is one of the original Manufacturers and the tensioner is a FEBI (Ferdinand Bilstein).

The boxes are in the first picture.

Good quality and purchased from M-B spares in Canberra Australia.

I will have all the original receipts and may even have the original quote form the main agent for the parts (Approx $2300) Vs non-OEM parts for about $700.

You cannot remove the bottom slider without taking the front off the motor - which was not the point of the exercise.
I think there is only one on the left side of the motor as the long tensioner slider does the job on the right side.

Bill
« Last Edit: 24 April 2007, 06:23 AM by WGB »

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Re: 450 - M117 Timing Chain Replacement
« Reply #13 on: 24 April 2007, 05:50 AM »
Bill, thanks for this excellent post, as I am about to embark on this job(minus cam sprokets) myself after discovering on Saturday that my tensioner on the 350SE was totally dead.  If some of the other 350 owners would like, I can post the part numbers for my 116.985 so they don't have to hassle with looking it all up.  After reading through your description of the job again, I was left with one question: you mentioned filling the new tensioner with oil...how did you do that?  I wasn't quite seeing it and didn't want to miss a vital step.

And since something on my 280 went awry, I might just slap a new tensioner on there in the next day or two(so I can quit borrowing my dad's SDL) and get the chain, guides, et al next weekend since I'm out of town this weekend.  Anyone know if it would have negative effects to put a new tensioner on without the rest for a few days?
Chad Johnson

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WGB

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Re: 450 - M117 Timing Chain Replacement
« Reply #14 on: 24 April 2007, 06:50 AM »
I was left with one question: you mentioned filling the new tensioner with oil...how did you do that?  I wasn't quite seeing it and didn't want to miss a vital step.

 Anyone know if it would have negative effects to put a new tensioner on without the rest for a few days?

I don't know if you have an Oz or Euro motor - the Euro tensioner has three holes you can see in the previous tensioner photos - two for mounting bolts and one is an oil hole. Immerse it in oil and make sure it is really full before bolting it up with a new gasket. I don't think it is possible to work the piston without a large amount of compression force but I can't really remember. Bolting it up compresses the piston and will push some of the oil out and dampen it before the oil pressure takes over when the engine starts.

Unless your chain is really worn a new tensioner should be adequate for a short term run but you will need two gaskets to make sure the final job keeps all the oil in when you are finished - so as not to re-use a gasket.

Two points of care not mentioned - to replace the sliders you will have to remove the sprockets whether you change them or not, just to give adequate clearance for removal and replacement of the slider pieces. You should use cable ties to hold the chain in position on the sprockets, then unbolt the sprockets while using a screwdriver through the sprocket hole to steady it and then keep the chain in tension so that it cannot move on the crankshaft sprocket .

The other point is that to remove the tensioner slider the lower pivot point has to be released. It is housed inside a cap low on the front of the motor. The cap is unscrewed and inside is a hollow pin which can be extracted by slipping a phillips head screwdriver into it and jiggling the tensioner arm and the screwdriver until it appears - may be worth tying a piece of wire to  the top of the slipper so that it doesn't drop too far but frommemory it can't drop right down.

I will place this in the main body of the post for easy reference

Bill