W108 4.5L Timing Chain Questions - Page 2 - Mercedes-Benz Forum

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post #11 of 17 (permalink) Old 08-08-2016, 09:02 AM
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Quote:
Originally Posted by rumb View Post
I would take out the tensioner. it removes slack on the backside of the chain. the other side is the one that has to line up the crank and cams.
Looking at the first diagram in this post illustrates this.



Removing or loosening the chain tensioner will allow the tensioner rail to hinge back and provide some slack on the passenger side. That should allow you to pull up on that side. Hopefully enough to reconnect the chain.

You could now see if you can apply tension to the tensioner rail. Try using a large screw driver or lever. If you can, re-install tensioner and see if you can rotate chain. See where the marks now are to see what next step might be.

Or at least that is what I would try, if I was in same situation.

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Last edited by MBGraham; 08-08-2016 at 09:05 AM.
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post #12 of 17 (permalink) Old 08-08-2016, 09:39 AM Thread Starter
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Quote:
Originally Posted by rumb View Post
I would take out the tensioner. it removes slack on the backside of the chain. the other side is the one that has to line up the crank and cams. Remember you were already 10 degrees which is one cam tooth off when you started.

This may be helpful also
PeachPartsWiki: M116/117 Timing Chain Replacement
Dang, that's the best walkthrough I've seen thus far! I had been looking for one like that! Thank you!

Quote:
Originally Posted by TZ_280SEL View Post
Which side are you working on first? I had a similar thing happen. I also dropped one end (on the Left hand side) and when I recovered it, it had a kink in it where two links had folded back on themselves. I had to drop it back down and coax the links to straighten out by pulling some slack back to the right hand bank, then pulling it back to the left hand bank with tension on it. Just remember, the engine isn't running and as long as you are not beating on things, you wont hurt it. Just make sure everything is at TDC and on the marks when you finish.
I started on the passenger side, and the right hand side dropped off. Thanks for the insight!

[QUOTE=MBGraham;14757218

Removing or loosening the chain tensioner will allow the tensioner rail to hinge back and provide some slack on the passenger side. That should allow you to pull up on that side. Hopefully enough to reconnect the chain.

You could now see if you can apply tension to the tensioner rail. Try using a large screw driver or lever. If you can, re-install tensioner and see if you can rotate chain. See where the marks now are to see what next step might be.

Or at least that is what I would try, if I was in same situation.[/QUOTE]

I think I understand the logic here. If I remove the tensioner, that should give me a bit more space to pull the two chain ends together. Then I can re-crank the engine around and get the original chain back to the marks I photographed, and start over? And just keep a close eye on the driver side cog to make sure nothing skips over there when I'm rotating.

I'm assuming the extra slack created between the driver and passenger cams is going to create a timing imbalance that I'll have to correct for once I rotate the engine around. Right?

Is this the process you're describing:

1) Remove the old tensioner.
2) Pull the LEFT side chain up to meet the RIGHT side (moving the left side two spots farther forward than it was before.
3) Reconnect the tensioner loosely, and reconnect the chain.
4) Rotate the engine back around 1 rotation, checking TDC along the way.
5) Mark chain position, remove to adjust cog position to re-set timing to the photographed positions below.
6) Crank till master link re-appears, and re-start feeding the new chain.
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post #13 of 17 (permalink) Old 08-08-2016, 10:01 AM Thread Starter
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Gents,

I just realized that I misinterpreted your solution to my problem. Please let me know if THIS is correct:

1) Remove tensioner.
2) Crank the passenger cam over slightly to allow me to put the dropped chain in its original position
3) Re-connect master link, crank the engine around, recheck timing.
4) If everything lines up (and it should, because everything is still in its original position), begin replacing chain.

I now understand that the purpose of removing the tensioner in this case is to allow me to get the dropped links back in their original position, not to move the chain up to meet the dropped links. That way, nothing gets out of timing. After the master link is back in, I can re-install the tensioner loosely and rotate the engine around to verify that we're all good. Yes?
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post #14 of 17 (permalink) Old 08-08-2016, 12:09 PM
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Just one thing. In both TZ_280SEL and ettS's posts there is reference to Left side and Right side. Convention is that these should be when sitting in driver's seat. So in NA, passenger side is Right side and Driver's side is Left side.

Seeing passenger (right) side of chain is still held to the sprocket, so long as you can rotate sprocket enough to reconnect the chain, presumably things will be back where they were. Hope so!

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post #15 of 17 (permalink) Old 08-08-2016, 12:38 PM
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W108 4.5L Timing Chain Questions

Quote:
Originally Posted by envoy_to_the_Stars View Post
Well, I have a bit of an unfortunate update.



I used "heavy duty" zip ties to hold the chain to the sprocket when removing the old master link. But Unfortunately, one of the ties snapped when I pulled the link out, letting the length of chain go limp and fall down.



I removed the guide and was able to recover the chain end, but I'm obviously not strong enough to recreate the tension that was on it originally. Therefore, I have a 2 link gap.



See: http://i.imgur.com/0ihPaTK.jpg



And: http://i.imgur.com/uJoc2zrr.jpg



Nothing else has been moved. I haven't taken out the tensioner, because I'm too concerned about creating more slack in the chain. I looked down into the engine, and the top idler pulley is still moving freely, and i haven't skipped any links there...I just cannot physically pull the chain hard enough to get it back to its original spot.



I'm not exactly sure how to proceed given the gap. HELP!


I HATE that people suggest using zip ties for this procedure. I had mine slip a tooth but not fall down the first time I did it. The amount of uncertainty and doubt it created in the whole process, making me take probably an extra hour or more to insert the new chain. Using vice grips, it's a 5 minute process IMO. Inserting the new chain is over by the time you start.


And yes, just remove the tensioner. You've got to do that at some point anyway.

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post #16 of 17 (permalink) Old 08-08-2016, 06:26 PM
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One thing when buying a tensioner, is to make sure you get the right one. There was a change early on and some overlap of engine numbers. Double check EPC. The OE MB tensioner costs about $350, but a Febi unit is around $100. I used the Febi tensioner and it has been good since installed in 2008 (Fill with oil before installing) Part #1160501611 for my early 72 350SL with M117 engine.

Only mention because local shop ordered wrong one for me.

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post #17 of 17 (permalink) Old 08-08-2016, 11:11 PM Thread Starter
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GREAT SUCCESS!

With the helpful hand of my girlfriend, we were able to re-position the chain and get it changed out with the new one. We also changed the tensioner. The guides were in great shape so we left those intact. Check out the before and after!

http://i.imgur.com/49IAYlT.jpg


Quote:
Originally Posted by MBGraham View Post
One thing when buying a tensioner, is to make sure you get the right one. There was a change early on and some overlap of engine numbers. Double check EPC. The OE MB tensioner costs about $350, but a Febi unit is around $100. I used the Febi tensioner and it has been good since installed in 2008 (Fill with oil before installing) Part #1160501611 for my early 72 350SL with M117 engine.

Only mention because local shop ordered wrong one for me.
PelicanParts did me right and got me the right tensioner the first time. I too chose the Febi tensioner. Just two 13mm bolts, a 8mm hex, and it's all swapped out! No special connections...couldn't be simpler.

Quote:
Originally Posted by Fonzi View Post
I HATE that people suggest using zip ties for this procedure. I had mine slip a tooth but not fall down the first time I did it. The amount of uncertainty and doubt it created in the whole process, making me take probably an extra hour or more to insert the new chain.
I agree with you 100%. There were about 5 times where I was terrified that I had skipped a tooth with zip ties. I switched over to vice grips, and my confidence was back!
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