how does cam tensioner work ? 87 560SL
 

I currently have the valve covers off on my '87 560SL & noticed that, at times, the timing chain appears very loose when I manually rotate the engine. (I know that the timing chain, rails, guides, and tension were all replaced very recently)

When searching thru various threads in this forum, I stumbled upon one that mentioned something about the tensioners working with oil pressure. Is this true ? If so, can this explain a substantial amount of timing chain "slop", when the engine is not running/zero oil pressure ?

Is there a wiki or a writeup somewhere that describes how these tensioners work ?

Thanks in advance,

Brian

Spring tension & oil pressure..

MB factory tensioners made after 1989 have a check valve to hold oil pressure longer.

How much tension should the chain have on it when there is no oil pressure ? I'm trying to understand if the slack I am seeing in my chain is normal.......in certain positions, I have, what seems like to me, a lot of play..e.g. the chain can flop quite a bit (e.g. I can flop it against the plastic guide and probably an inch in the other direction)....in other positions it seems very tight.

Thanks,

Brian

tensioner works with spring an oil pressure while turning the engine by hand the tensioner will be loose. its when you start the engine if you hear the chain slap at start up then its time to change the timing chain do to chain stretch. If this work has recently been done then you your chain should be ok don't be to concerned on the alignment mark on the cam that is not how you check for proper cam timing need dial indicator to do this properly..
Bob