blackboy

Hi all, I have an 88' 911 Turbo that is starting to develop a bit of a problem. Sometimes,when I start the car a very loud noise that sounds like chains rattling emanates from the engine.
If I shut the engine off and restart it the noise will go away, but not always on the first try.
After the clatter stops the car runs as if nothing was ever wrong, again this is only on start-up the noise has never surfaced after the car was running.
On one occasion when the noise occured I gave it a little gas and the noise dissappeared.
Anyone have any suggestions or ideas on what this might be. Thanks.

A930Rocket

Timing chain issue?

PorschePhD

Sounds like a failing chain tensioner. They loose pressure when the car is off and will build back up when started. What year is your car?

Sameer

Fan belt might need to be tightened?

Gino

Agreed, sounds like chain tensioners. I'm no expert, just experienced.

In my 951 I had the same issue but with the timing belt. the belt needed replacement because the auto tensioner couldn't tighten it any more. it was loose and would bang against the cover/ housing, especially when cold. the noise kinda went away as the car warmed up, and when you gave it gas (put a load on the belt, essentially straightening and putting pressure on it) there was no noise. I understand that was typical at 90k, and recommended service.

I doubt the chain is 'overstretched', but it could be the tensioners...

jrogers

This sound exactly like the problem I have been having for some time. In my case, I have noticed that if the car is parked on a slope with the nose down. it does it much less often when the care is parked on a slope nose up. I would describe it a almost a rod knock, but I could be convinced that it is a timing chain sound as well. I am curious to see if you find a solution. I don't think it is in the timing chans in my case, since I have had all of this replaced and it still does it. The only clue I have is that during my last valve adjustment the rod that holds the rocker arms on had moved. These are hold in place with set screws, and I think one was loose, but the others were tight. The mechanic loosened them and reset them where they should be, but he did not know why they would have moved like they did. This was the first valvle adjustment since a rebuild, so I plan on checking it again this fall. Maybe there is some strange allignment problem in the top end?

blackboy

Sorry to take so long to acknowledge your responses. Thanks to all. Stephen my car is an 88 with 50k mileage. Now for some more questions. How do I go about determining what the exact cause is for one.
Also, this has only happened to me about 4 times in the past six weeks.
If it is the chain tensioners, how big of a job is it. Is this in need of immediate attention or can it wait awhile to be repaired.
Speaking of repairing , how much time in labor can I expect a mechanic to put in and what parts are involved.
Thanks again for all your insight.

jrogers

Another theory I had on mine was that it may be the starter not releasing all the way. Please update this thread if you finda solution. My problem is that I can never get it to do it in front of a mechanic.