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Greek God of the R129
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Discussion Starter #1
I was just wondering.
How many of you have changed the timing chain, and at what mileage?
And at what engine size?

Regards,
aam.
 

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Good day, 96 SL320 65,900 mi. original chain, no problems
SL500 1993, 148K, the chain chewed most of the keepers (guides) at the top, replaced all at 138K.

The chain itself was within specs, so we didnt replace it... the chain typically streches beyond specs around 100K, so we're thinking the previous owner replaced it early.
 

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Greek God of the R129
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Discussion Starter #4
I am bringing this up again....

I was asking for chain work, etc.

As you can see Bayhas had work on the guides.
Bayhas, do you happen to remember the proximate cost & labor?

A bad chain tensioner can also let all Hell lose.

Regards,
aam.
 

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The double row chains are pretty robust. I just rebuilt the topend on my 160k mile m111 in my w202. The m111 is a m104 minus 2 cyl. I was really suprised..the piston walls still had factory score marks. I re timed the engine from scratch when I was done and everything lined up perfect so the chain was still in spec. It can be a few degrees off due to stretch and the engine will compensate for it but it looked right on point. The guide rails all looked new ....the only thing I changed was the tensioner. I did notice the difference in the two springs in the tensioners, the old one was a lot softer. I don't see the guide rails being chewed up without there being an issue with the tensioner or a really stretched chain I guess. IMHO I wouldnt worry about it unless I heard it making funny noises...you could change the tensioner to be on the safe side. If you do decide to have it changed they shouldn't have to take the lower chain cover off to get the new chain on the crankshaft gear. They can attatch it to the old chain with just the upper cover off and feed the new one on. I would do the upper rails at that point just because. Its not too bad of a DIY either just mark the chain and cams, set the timing so you can spin the crank without the valves touching the pistons, lock the cams, take the exhaust cams off and feed the new chain....easy
 

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Greek God of the R129
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Discussion Starter #6
Yes,
MB had a problem with the single chain, that is now history.

On a cold engine, especially in cold wqeather areas the tension is held by the tensioners spring, then when the oil pressure kicks in it is hydraulically pushed.
So if is freezing temperature by the time the oil pushes on the tensioner is too late.
The chain has jumped..... :(

As you have seen the chain stretches a bit, but the whole picture is that the tensioner spring gets weak, gears, guides, also wear out so a little here a little there......

A good forum member has an engine problem.
I will keep him anonymous, if he sees this he may comment.
At about 190K I think his engine jumped a few teeth, now he is torn
between getting an other used engine or rebuild his...

When an engine misses, the timing system vibrates, so there goes the chain jump.

Regards,
aam.
 

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Ahh I forgot your engine uses the hydraulic tensioner that uses oil pressure to keep it tight. In that case I can see where they can cause problems with the rails. Not only do you have to worry about the cold they can leak too. The tensioner I changed on my w202 is the ratcheting type that always stays tight and moves out more as the chain stretches.
 

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Replaced all the tensioning rails on a 500sl r129
at 70k miles the chain appeared well within specifications.
 

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Single row 103 motors were bulletproof, I had one with almost 300k which is pretty common. Of course they have only two sprockets. Three sprocket double row 104 motors seem to be fine too. The only problems you hear about are the ones that have been "fixed" somehow, that is factory work molested in some way. 119 motors are only about a hundred dollars for the upper guides and the valve cover gaskets, in parts that is. If you really want to keep the cost down just do the right side for half of that.
 

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Greek God of the R129
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Discussion Starter #11
Single row 103 motors were bulletproof, I had one with almost 300k which is pretty common. Of course they have only two sprockets. Three sprocket double row 104 motors seem to be fine too. The only problems you hear about are the ones that have been "fixed" somehow, that is factory work molested in some way. 119 motors are only about a hundred dollars for the upper guides and the valve cover gaskets, in parts that is. If you really want to keep the cost down just do the right side for half of that.

I am with you...

The simpler the engine is the less the troubles.

But it is nice to have a beautiful, exiting high maintenance blonde on your side. ;)

Wouldn't you say? Haha.

Regards,
aam.
 

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Hi aam,

Changed mine at 64t km, since the engine and transmission was out, during repainting. I also changed the top guides and tensioner, together with all exterior oil seals. At that mileage, all were still good, but changed them anyway.
 

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Greek God of the R129
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Discussion Starter #13
Chicky I admire your work.

You did/do a great job. :)

Regards,
aam.
 

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:eek: . thank you for the compliment aam!

In most of the posts that I've read about the timing chain, the reason they were changed, was more of finding out that the top guides broke and changing of the chain was the prudent thing to do.

BTW, +1 on "it would really be nice to have a beautiful woman" ;)
 

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Greek God of the R129
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Discussion Starter #15
:eek: . thank you for the compliment aam!

In most of the posts that I've read about the timing chain, the reason they were changed, was more of finding out that the top guides broke and changing of the chain was the prudent thing to do.

BTW, +1 on "it would really be nice to have a beautiful woman" ;)
Every case is different, but it would be penny foolish to have all that work
done and not replace the chain after all it is only about $150.

Be aware that beautiful women can and will take us to the cleaners.
(I am older. ) Lol.

Regards,
aam.
 

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Help, I need some advice.....
My 1992 500 SL has now over 265,000 miles on the clock. The car is in showroom condition. A rattling sound when start up. Either I was going to replace the timing chain tensioner/large guide and rails or look for a low milage engine. Last week I decided to keep the engine and replace the tensioner and tensioner guide, and all the top rails. So yesterday and today I replaced the top rails, all the head rails, timing chain tensioner and its guide, all without removing the timing case cover in which I dread doing. The chain and cam sprockets all look fine. However If I try to turn the crank and set the timing mark on 45 degree TDC, 2 right side cams barley cannot be pinned but the 2 left side cams can be pinned. If I moved the crank to 39 degree (pic 1) or just short of 40 degree, the right side cams can be pinned (pic 2) but the left side I can barley pin the cams (pic #). I’ve rotated the crank several times and the readings keeps coming up the same.
1. Is my Timing Chain Stretch?.
2. Should I replace the Timing chain?.
3. If so, do I need to remove the timing case cover to replace with a new chain or can I roll in a chain without the removal of the T cover?.
Oh, forgot to mention that the engine is in the car, also the condition of the old rails, 4 rails were broken in half and 2 broken in 3s'.....
 

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Help, I need some advice.....
My 1992 500 SL has now over 265,000 miles on the clock. The car is in showroom condition. A rattling sound when start up. Either I was going to replace the timing chain tensioner/large guide and rails or look for a low milage engine. Last week I decided to keep the engine and replace the tensioner and tensioner guide, and all the top rails. So yesterday and today I replaced the top rails, all the head rails, timing chain tensioner and its guide, all without removing the timing case cover in which I dread doing. The chain and cam sprockets all look fine. However If I try to turn the crank and set the timing mark on 45 degree TDC, 2 right side cams barley cannot be pinned but the 2 left side cams can be pinned. If I moved the crank to 39 degree (pic 1) or just short of 40 degree, the right side cams can be pinned (pic 2) but the left side I can barley pin the cams (pic #). I’ve rotated the crank several times and the readings keeps coming up the same.
1. Is my Timing Chain Stretch?.
2. Should I replace the Timing chain?.
3. If so, do I need to remove the timing case cover to replace with a new chain or can I roll in a chain without the removal of the T cover?.
Oh, forgot to mention that the engine is in the car, also the condition of the old rails, 4 rails were broken in half and 2 broken in 3s'.....
Can anyone please chime in. I'm anxious to button of the engine, but I really need some advice. Can anyone PLEASE tell me how to calculate, do the pictures help..... thanks
 

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I believe the spec is 45 deg. I think all is good. Why they did not so it at TDC is beyond me, but it would not run if the cams were off 45 deg.
 

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timing chains

Can anyone please chime in. I'm anxious to button of the engine, but I really need some advice. Can anyone PLEASE tell me how to calculate, do the pictures help..... thanks
I have a technical all makes cd which gives some info on how to do these, probably can't legally post it in here but if you pm me I can try to extract it and email it to you, cheers, Jim.:)
 
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