560SEC Timing Chain and Guides ready to replace? - Page 2 - PeachParts Mercedes-Benz Forum

JohninFla · #16 11-07-2001, 10:11 PM

Ok, I am betting it is the same as my 560SEL, but I am not sure if there is some upgrade to the 560 coupes in this area. My CD Rom does not say so, but you never know.

I replaced the upper guides and timing chain at 125K miles. They were really brittle, the color of a beer bottle. I was told the lower guides, down near the crankshaft, never go so not to worry. Also, pulling the front cover to replace them is a huge job, requiring removing the front head bolts. And removing the front head bolts risks pulling threads out of the Aluminum block, requiring removal of the heads to helicoil the holes and fix this. Big job I had no desire to perform.

You are right about the hole below the cam gear; it has an uncanny way of sucking parts into it! I strongly recommend stuffing a clean rag in there the second you remove the valve cover!

Anyway, I snuck the upper chain guides out by removing the cam gear while the chain was tie wrapped to the gear. Be careful not to let the chain drop far enough to get off the crank gear while you are doing it. I think I posted something about my work, replacing the chain, rails and cam gears. Poke around the search under my name.

Also, you will need a way to remove the rail pins. I fabricated a tool with a couple of M8 or M6 bolts, I forget which thread. I used them to pull the dowel pins. You may wish to invest in a couple of these before you start; I butched the threads on one of mine and had to wait until Monday when the MB dealer opened to grab a new one and finish the job.

There is a way to check the chain for stretch. You line up the timing marks on the crank at zero, and see where your timing marks on each camshaft ends up. There is a way to correlate the distance from the mark on the shaft to the mark on the head to degrees of stretch. This tells you how many degrees of stretch you have, and there is something in the manual about what is tolerable. Not sure what it is, (it has been a year or so since I did it), but I know mine were right on the money after the new chain, tensioner and rails were done.

I hope this helped you out. Let me know if I can answer anything for you. My grubby paws have been in there, so I might offer some insight. Good luck!

barndoor · #17 01-06-2002, 03:07 PM

does anyone know if it is mandatory to replace the head bolts on an '85 380SE (V-8 126) when installing a rebuilt head?The bolts are very high quality,I had no problems removing them,threads are good.The car has 145k.

autozen · #18 01-10-2002, 11:43 PM

You may not think any one was listening,but I was listening. I agree with your question. How can a chain give a rat's ass which way a master link goes? In the old days when I was ayoung apprentice at the dealer the master links came with a single clip that went on in the direction of chain travel. Apparently there was some problem with the design,because they went to two tiny clips on the gas engines and a rivet on the diesels.I never bought the tool because I have ball peen hammers.I wonder how many people know the purpose of a ball peen.One is as I described and another is to make gaskets.Make gaskets? I always break the old chain with a die grinder and peen the new master link. Been doin it for twenty years.At any rate I thought your aside was refreshing.
Peter

dpetryk · #19 01-11-2002, 08:29 AM

Ok Ill just have to chime in on the subject of the master link. I too have read the threads here and have seen differing opions. I talked to the local MB dealers in Houston and 2 of them confirmed that the link goes on the front of the chain, and is installed as shown in the attached photo. The closed end of the link should be on the leading edge of the direction of travel. I can envision a number of reasons for this. There are centrifigal forces acting on the link trying to pry it open. It probably makes contact with the rails and tensioner as it passes over them and friction would want to make it slide in the oposite direction of the chain movement. So it stands to reason in my mind that one would want to install the link so it tends to push it in the direction of the closed end. Otherwise it might be able to push the clip off. So you orient it so the friction forces push the clip on. Makes sense to me.

So looking at the front of the chain it should be installed as shown here. The MB dealers also stated that they do not use the press tool to flare the master link and they only use the clip type link. So thats the way its done in Houston. Hope this helps.

autozen · #20 01-11-2002, 11:16 AM

The type of clip shown in the photo is the directional clip I mentioned MB used to use.I haven't seen one in years.I did a valve job on a 560SEC a few months ago(sucking a quart every 30 miles)and the new chain came with 2 tiny circlips like always.Also it's my experience that the diesel master links are rivet type which you can peen if you don't want to use that silly tool.For some jobs MB designs tools that you can't do the job without.A good example is the ball joint for many models.On the other hand you wonder what they were thinking with some of their tools.A good example is the special tool to hold the fan clutch on a M103 engine.An allen wrench stuck in a short section of 5mm hose works fine.Anyway I'm curious if anyone has recently bought a chain with a clip like the one pictured.Perhaps I need to stop ordering my parts out of Russia.
Peter

dpetryk · #21 01-11-2002, 12:03 PM

That chain was replaced on my 91 420. I changed it in August of 2001. The chain from the dealer had the identical clip on it.

autozen · #22 01-11-2002, 12:38 PM

VEEERY INTERESTING.I'm going to check with shop owners in the area to see what they are getting.The ones I've been getting from Germany may be different.I'll let you know.

Regarbs,
Peter

mplafleur · #23 01-11-2002, 05:04 PM

autozen,

Thanks for noticing. I of course was refering only to a rivet style, not a clip style. I didn't know that anyone made clip style master links anymore. I myself would not trust them.

engatwork · #24 01-11-2002, 06:23 PM

autozen - thanks for saving me crimp tool rental fee for the next chain I crimp on. I had forgotten about a ball peen hammer. What do you use to "back up" the link with when hitting it with the ball peen hammer?

The ONLY time I would use the link as shown in the picture is to connect the new/old chain together to roll the new one in. I have used the type as shown on motorcycle final drives but they got replaced quite often compared to a MB timing chain. There is too much cost involved if/when it fails. I recently purchased a new chain from the dealer for the 240D and it came with a crimp style link.

autozen · #25 01-12-2002, 12:33 PM

The answer should be obvious;the flat end of a bigger ball peen hammer.Now here's where you say;why didn't I think of that? I'm glad I was able to save you some money,Jim.I have installed diesel chains this way for years as a professional MB mechanic without a problem.Just remember the operative word is peen.Don't beat the crap out of it.
Good luck
Peter

CloudNine · #26 01-17-2002, 04:27 PM

Well, I have watched this thread morph with a fascinated interest. What was originally my question about when to change the timing chain morphed into a fascinating discussion about which direction the link should face. Love the detail.

Well anyway, I finally got the answer I was looking for from the Technical Letters section of the most recent Star magazine.

The editor says (for duplex only):

100k miles: change not necessary, but will noticeably improve performance.

150k miles: change recommended soon.

200k miles: change now, performance will improve greatly.

If you have a single chain, then convert it to duplex as soon as possible.

Thanks all for your comments. :p

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