Author Topic: Timing Chain & Upper Rails Replacement  (Read 9542 times)

rwmastel

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Timing Chain & Upper Rails Replacement
« on: February 19, 2003, 21:50:24 »
Hi.  I have all the parts, the MB service manual (BBB), the Haynes manual, and the MB Spare Parts List, but I don't have any experience with this at all.  Who has hints & tips for this process that would not be covered in the books?

Many thanks!

Rodd
1966 230SL Euro
1994 E420
« Last Edit: February 19, 2003, 21:51:18 by rwmastel »
Rodd

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Tom

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Re: Timing Chain & Upper Rails Replacement
« Reply #1 on: February 20, 2003, 07:26:09 »
Rodd,

I have done this. No special tips to offer, but a couple of thoughts:

1. Remove all the spark plugs and protect the plug openings from stray bolts, etc that could fall into the openings. This will ease engine rotation and chain replacement. Just as an historical reference, check to see how much stretch you have in the existing old chain by lining up the timing marks on the camshaft and checking the degrees on the vibration damper on crankshaft. It's just nice to know how much physical improvement to the timing you will achieve with your hard work-and the car will perform better!

2. Remember that the crankshaft rotations and cam shaft are different-you are only sure to be at TDC if the crankshaft & distributor notch indicate TDC.

3. Before you remove the chain, tie a string to the chain to keep it from falling down into the engine. You will likely have to grind the link on the chain to break the chain. Put a rag under the chain to prevent metal parts from falling into the front of the inside of the engine-Don't forget to remove the rag.

4. I am sure the book is good about how to thread the chain such that the new chain essentially replaces the old chain while avoiding a miss in a link (which would throw timing off). The book also will get into detail about how to line up the timing to ensure the engine timing is right when you begin the replacement.  You will get a c clip with the kit to attach the old and new chain to create one continuous chain that can be thread through the sprockets. This same clip will be used to permanently close the new chain. While I am not sure it matters, some recommend that the c clip be installed such that the closed end of the c clip goes in the direction that the chain travels-gives peace of mind that the clip is less likely to come off.

You did not mention the chain tensioner, but if you are replacing the sprockets and chain, you may want to go ahead and replace the chain tensioner and bleed it once installed.

Hope this helps!
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rwmastel

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Re: Timing Chain & Upper Rails Replacement
« Reply #2 on: February 20, 2003, 08:32:02 »
quote:
You did not mention the chain tensioner, but if you are replacing the sprockets and chain, you may want to go ahead and replace the chain tensioner and bleed it once installed.


I got advise that the tensioners on these in-line 6 engines (127, 129, 130) seldom fail and that they should not be replaced unless there is evidence that they are not functioning.  Mine is functioning.  Thanks for thinking of the tangible tasks to my job, that's what keeps people from doing jobs twice.

Rodd
1966 230SL Euro
1994 E420
Rodd

Did you search the forum before asking?
2017 C43 AMG
2006 Wrangler Rubicon
1980 450SL
1966 230SL