Porsche Repair: 1974, 911 Tension Timer, chain tensioners, porsche 911

Question
Hi Dave,

I have just bought my first porsche 2 weeks ago a 1974 porsche 911 Targa 2.7 Litre.
My question is simple......as a precaution measure I wish to know how many kilometres/miles approximately the tension timer needs changing before the tension timer collapses on these particular models?

Note: the car has run 51 thousand miles.  

Answer
Hi Julio,

Sorry this response was delayed..the system wouldn't accept it the last couple days.  Anyway here it is:

I've never been fortunate as you to have owned a 911, so this is an issue I have no personal experience with.  I was surprised a bit by your question because I always considered the 911 engine to be free of "tensioner" headaches (unlike the 944).  But you have raised an interesting point and I have learned a bit along the way.

Let's first make sure we are speaking of the same thing.  I believe you are referring to the "chain tensioner", actually the TWO chain tensioners on the 911 engine.  Each camshaft is driven by a chain linked with the crankshaft and each chain is held at a certain "tension" by the chain tensioner.  

The issue appears to be as the tensioners age and wear creeps in the possibility of slack in the chain develops.  Slack is bad.  I would use the following article as an excellent guide as to the possible problems and the solutions to the question you've raised:

http://www.pelicanparts.com/techarticles/911_carrera_chain_tensioners/911_carrer...

I have found this website to be extrememly useful and I hope you do to.  I'll have to give you a gold star for thinking about chain tensioners as a maintenance items and renewing them as a precaution.  I commend you and I can imagine your new car will enjoy its life being pampered by you.

Best of luck with your new prize.

Dave