chain tensioners-when to replace
 

3.0 motor with 106k miles-motor makes a soft groan at startup for approx. 2-3 seconds. Could this be a tensioner starting to fail. Also is it possible to replace the timing chains without retiming cams.

I replaced mine (upgraded to the hydraulic ones) recently (83-911SC 93kmi) and am amazed at the change in the sound of the engine. I must have gotten used to the rattle of the chains over the years without knowing it. It now sounds very smooth. An old mechanic at San Mateo Motors suggested that it was time for the upgrade by simply listening. At the time, I could not hear a thing. If you can hear yours, I think it is time for change.

BTW, my old tensioners seemed very stiff. I'm not sure how to test them, but I can not see anything wrong with them. In fact, when I took them out I figured I had wasted my money. All thoughts of this were forgotten the moment I fired it up.

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Graham Archer
83 911SC Cab

SC,
Hard to tell from here if a "groan" is a failing chain tensioner. However, if you are going to up-grade to pressure fed chain tensioners, you are doing it as insurance against the eventual failure of your current tensioners. Since you don't know when this will happen, then upgrade them now. No need to wait for your insurance.
To replace the chains you will need to split the old chain and attach the new chain to it and turn the engine over (by hand) which will feed the old chain out and pull the new chain in around the sprocket. You should not have to replace the chains unless they have stretched so far that the tensioners will not take out the slack.
If you do replace the chains, you will have to retime the cams.
Bob W.