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 05-26-2003, 12:11 PM
aly
Guest
 
Posts: n/a
Unhappy chain slack

hey it's me again...i finally finished installing the chain on my 4.5 V8, and i installed the rails and tensioner and all, i crancked the engine by hand CW and everythng seems ok, but when i cranck it CCw the chain slcks to the extent that i can pull it off the distributer gear...is this normal?

Reply With Quote
  #2  
Old 05-26-2003, 12:32 PM
MikeTangas's Avatar
Senior Member
 
Join Date: Apr 2000
Location: So. Cal
Posts: 4,430
Why would you turn the engine counter clockwise? If you were able to turn it clockwise through at least two complete revolutions you should be good to go.

If you haven't fired up the engine since the chain and tensioner replacement, the tensioner hasn't pumped up and only the spring tension of the tensioner is supporting the chain.

Roll it over clockwise through two complete revolutions yet again, to be sure you haven't messed with the cam timing. If all goes well, put it back together and fire it up.
__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.
Reply With Quote
  #3  
Old 05-26-2003, 12:44 PM
aly
Guest
 
Posts: n/a
thanks i did crank over two revs, and it looks ok, the timing took me a while to get right but it's good now. how does the tensioner work exactley?
Reply With Quote
  #4  
Old 05-26-2003, 12:55 PM
MikeTangas's Avatar
Senior Member
 
Join Date: Apr 2000
Location: So. Cal
Posts: 4,430
I can't tell you how it works "exactly", but I'll give you a general how it does.

The push rod on the tensioner contacts the tensioning rail, pushing the chain toward center, in effect removing any slack. When the engine is run, the oil, which is now under pressure, enters the tensioner at pressure, further tightening the chain. There should be a check valve inside the tensioner which will keep the push rod extended even when the engine isn't being run, so the chain is properly tensioned at the next start-up. As the tensioner gets old, the check valve leaks down, and that main spring you had to work so hard to compress (to install the new tensioner) gets weak. Lack of retained oil pressure and that weak spring cause chain rattle at start-up, continued chain rattle can cause a chain failure resulting in several thousand dollars of damage.

Again, roll it over through two complete revolutions before you do anything (I'm a little OCD when it comes to hand cranking, I'll go four complete revs - on the 560 I did six, only to learn it takes six and half to make the chain complete one revolution). If the timing has somehow gotten off, you will eat valves on your first attempt to start.
__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.
Reply With Quote
  #5  
Old 05-26-2003, 01:22 PM
aly
Guest
 
Posts: n/a
will do ! thanks a lot for your help

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 07:49 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