chain,guide,rail inspection 560 SEL

[emmydotnet]

I finally got the courage to check the chain stretch using the cam timing mark method.

I opened the valve covers, aligned the mark on the right cam onto the mark on the tower, then read the timing mark on the crankshaft. It read at 5 to the left of the big ZERO. Here is an illustration:

pointer was between the small zero(left) and the big zero.

2|o|1|o|0|1|o|2|o

I also tried to look for the master link on the chain, but no luck. I could not figure out which one. I guess I do not really know what i was looking for. any help on this would be great.

The guides, and rail appear to be good. no cracks or missing parts. except for the color which i describe to be brown to slight dark brown.

There is this rod on top of the cam with plastic covers on the ends and about 3 more in between. I guess these are the cam oilers. The color of the plastic on the right side was brown, but the one on the left(driver's) was very dark brown.

My questions:
1. should I replace the chain? I have 150,000 miles on the car.
2. should I just repalce the upper guides and the rail?
3. what about the tensioner? should I replace it too?
4. any comments on the cam oilers? do I replace the plastics?
5. Is there another method to look for the master link? or is it important to know if the chain has been replaced before? Is the test for stretch adequate to make a decision?

The car starts fine and runs fine. to noises at startup whatsoever.

I have some pics but could not figure out how to paste them onto the body. any help on this would be great.

thx,

[stevebfl]

Yes, replace everything. I'd flip a coin on the tentioner. The chain probably doesn't have a master link and it will have to be cut (the rivets are ground off a link with a carbide cutter and a link is disassembled. We then keep a clip style link to join the new chain to the old to roll through the motor. Then we install and crimp the permanent style master link.

The oilers are easy so I'd probably just replace them but there really is no need as long as the tube is firmly mounted (no loose attachments).

Hello,

I recently went through this routine on the 82 500 SL with the 117.962 engine. My markings on the harmonic balancer are different so no comment on your markings, as far as how much strecth you have. On the chain, I selected a link at random and ground off the ends with a Dremel in just a few minutes. I replaced the chain and promptly lost one of the 2 microscopic e-clips (I felt that peening the new master link was a bit dicey for me). I could have gotten a new master link from our sponsor here but did not want to wait. I checked every hardware and tractor supply store in what seemed like all of Ohio for a replacement e-clip without success because the lost one is smaller than anyone carries. As a solution, I went to my local hardware store and got a #35 master link (it has one retaining clip instead of the 2 e-clips) and it fit like a glove. I faced the opening of the fastening clip away from the direction of travel.

Good luck. I just wanted to share this solution in case anyone else losers one of the little buggers.

RIch Mayer
82 500 SL

[emmydotnet]

Rick:
thx for the reminder..

Steve:
In a number of your responses regarding chain replacement issue, you had mentioned that the upper guides and rail should be replaced rather than the chain, since it is these parts that do brake. I am sure your opinion is based on specific situations, so would you comment on why you would recommend replacing the chain in my case? Is it because of the chain stretch as I have noted? or is it because of the mileage( at 150,000 miles)? I have driven the car for about 30,000 miles since I bought it 4 years ago, so I figure it would take about 5 to 6 years for me to put in another 50,000 miles...

thx,
emmy

[greenacres2]

Emmy,
I was able to remove 15 rocker arms without breaking an oiler fitting, then on the 16 i cracked one with the valve spring compressor. Cheap to have on hand, and if you need them, it will save a few days. My old ones were brittle. I could have used the old tubes, but i replaced them anyway, kept the old ones for "what if". Hope this helps.
P.S. I have a spare master link if you want it. Chain comes with one, but i ordered another just in case--didn't need it.

[stevebfl]

Since you drive a small amount of miles you really don't have much risk. When asked I advise 150-200,000 miles on the chain. It is overkill though as all the failures start with the rails (or an improperly set masterlink after the chain IS replaced).

[emmydotnet]

Steve:
Thank you so much for the clarification. I am inclined to follow thomas pindelski's model by replacing the guide, rails,tensioner and recheck the chain. but then again, i might go all the way if i feel brave enough.

Hey Earl,
did you have some kind of procedure that you used when you did your chain? Im wondering what subtle things i need to know to prevent careless mistakes?

thx'
emmy

[greenacres2]

Did mine with the front cover off and just laid it in. NOT the method of choice. Mike Tangas (username=mtangas i think) did a great job explaining the 560 chain roll-in in a thread titled "560 sel accomplishments". The best step by step photo layout was by Thomas Pindalski (username=thomaspin) but his is a subscription site now. I would feel confident trying to roll one in now that i have seen how it works, but am not the one to describe it.