Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 05-25-2009, 11:54 AM
Registered User
 
Join Date: Sep 2003
Location: Suburban Washington DC
Posts: 892
94 E420 timing chain guide broke into engine. Is that a problem?

Here is the right head with the guide intact:


On the left head the top part of the guide is missing and all I found when taking the cover off are pieces I have placed on the power steering reservoir:


It could have been like this for many thousands of miles without a problem so should I worry about it now? I assume any big chunks would just drop to the bottom of the pan and any small bits that would have gotten past the oil pump screen would have been pulverized by the pump and caught by the filter. The car runs fine with strong oil pressure. What parts do I have to replace and how do I tell if the chain is worn? It has over 160K miles.

Reply With Quote
  #2  
Old 05-25-2009, 01:25 PM
Registered User
 
Join Date: Aug 2002
Location: Southeastern PA
Posts: 3,077
atikovi, one of the broken pieces could cause the timing chain to jump one tooth, or more, and trash the engine. If it were me I would drop the oil pan and remove all the broken pieces and install new timing chain guides on both sides. It's not worth the risk leaving broken pieces inside the engine.
__________________
Fred Hoelzle
Reply With Quote
  #3  
Old 05-25-2009, 02:28 PM
Registered User
 
Join Date: Aug 2008
Posts: 436
You ask about chain stretch- but I believe you are looking at the evidence of chain stretch!
Yes, it can be checked. Rotate engine around on TDC(turning it clockwise) and then see where the RHS cam is with respect to the timing mark. I bet it's way out- 10-20 degrees.
Yes, you'd be best to remove all the pieces. It could be in the cover still and lodge with sprocket-cause chain breakage- and then your in for an added valve job.
Looks like your in for a big job- read up on replacing the chain. Big job. I'd use on a wjis chain and factory guides. Replace as main guides as you can get at. FYI I've never done one on a M119 engine-yet.

M
Reply With Quote
  #4  
Old 05-25-2009, 08:00 PM
Registered User
 
Join Date: Oct 2008
Posts: 557
I would say...not a big deal...I would look into this thing however, like you say, you don't know long it's been like this and it hasn't caused any issues and, frankly (and don't take this to heart young people) it is an extremley bullcrap issue anyway...if it fell of into you timing chain assembly you wouldn't know about it? A dual roller-chain timing assembly held together with a plastic cover? No...absolutely not....it's a cover that probably got tossed by a mechanic at some prior servicing.....he decided to toss it rather than charge (and piss off) you for it to be replaced ...forget about this....
Reply With Quote
  #5  
Old 05-25-2009, 08:29 PM
Registered User
 
Join Date: Sep 2003
Location: Suburban Washington DC
Posts: 892
I'll replace both since the one still there is cracked and can go anytime. Since it's made of brittle plastic I'm not too worried about it causing damage from lodging in the sprocket, the chain will just grind it up.
Reply With Quote
  #6  
Old 05-25-2009, 11:55 PM
Registered User
 
Join Date: May 2007
Location: Arizona
Posts: 760
I changed mine a while back. Maybe this post will be of help to you.

400E Upper Chain Guides

Regarding the timing chain stretch, I was never able to get a definitive answer on how to check it. The job in the shop manual (attached) has a procedure for "[c]hecking, adjusting basic setting of camshafts," and it has you pin all 4 camshaft sprockets with the 6.5 mm pins at the camshaft bearing caps, after turning the engine so the vibration damper is at 45 degrees BTDC. It says that "it must be possible to pin the camshafts with the pins," but it does not say what it means if you cannot do this. Then it goes on to tell you to "fit on" the timing chain (maybe I missed it, but I can't find where it has you take it off).

I was wondering if you could check for stretch by turning the engine until the pins did align, then check the damper to see how far off from 45 degrees it is.

Any thoughts on this?
Attached Files
File Type: pdf 05-2230.pdf (61.9 KB, 187 views)
__________________
1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles
Reply With Quote
  #7  
Old 05-26-2009, 07:35 AM
Registered User
 
Join Date: Sep 2003
Location: Suburban Washington DC
Posts: 892
Thanks for the link. As for checking chain stretch, that's way too complicated to go through. I just want check it how you did with a finger pull up on the chain between the cam sprockets. Mine seems much tighter than your pictures so it must be OK.
Reply With Quote
  #8  
Old 05-26-2009, 05:04 PM
Registered User
 
Join Date: May 2007
Location: Arizona
Posts: 760
I'm not sure that what I did is a true reflection of the chain stretch. My chain tensioner could have been weaker than yours at the time. My feeling was that, even if the chain was stretched, the new upper guides would have at least reduced the likelihood that it would jump a sprocket tooth and take out some valves.

Snaking a new chain in is a job that I know is beyond my mechanical abilities. I considered just changing the tensioner, which only involves having to pin the passenger side cams with the 6.5 mm pins (this prevents the chain from jumping the cam sprockets when the tensioner is removed). In any case, it's moot now, because that car is in the junkyard.

__________________
1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 06:16 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page