Timing Chain 500 SEC

I have heard that at a certain mileage it's a good idea to replace the timing chain guides (which are plastic). However, I am not sure whether or not the timing chain itself needs to be replaced.... Heard some say yes and
some so no. Any views out there? 1985 M117-963, 170.000 miles.
David in Seattle
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
David,
I would replace the chain every 100,000 miles, and the chain tensioner as well if possible. This was done on my 500SE (1990) at 126,000 miles. In my case, the (duplex) chain did show some signs of wear, so I was glad it had been replaced. It had started to rattle from start-up.
I've seen some scare stories about the guides going brown, becoming brittle and then breaking, but I have never been able to confirm them. It's quite likely that the guides broke AFTER the worn chain started hitting them. But if you are going to change the chain, then do the tensioner (and the guides) as well. At 170,000 miles, I think the sooner you do it the better!
Regards, Al, Caversham UK 1990 500SE 137,000 miles 1988 260E 160,000 miles FOR SALE

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The timing chain should be renewed when stretch is unacceptible. You can measure the degrees of chain stretch easily with the timing marks on the cam towers.
At 170K miles the chain can still be well within spec if the coil changes were kept up. If they wern't (and it doesnt' really take long) then you'll probably need a new chain, and possibly tensionor as well. Guide you replace "as long as you're in there". In very broad rough terms you should get 2 chains and one set of guides per million miles of engine.
--
Need Mercedes parts ? - http://parts.mbz.org
http://www.mbz.org | Mercedes Mailing lists: http://lists.mbz.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 2005-02-04 15:01:24 -0800, snipped-for-privacy@vrx.news (Richard Sexton) said:

<snip>
That might be true, but in my experience 100K miles is the right time to replace a timing chain in most vehicles. Usually at that point there is enough wear and tear to make this replacement a good idea.
Marty
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.