Chain tensioners:What/Where are they and what do they do?
 

I see articles on how to do upgrades, but I can't seem to find anything that explains what they do and what the effect of worn or bad tensioners is....Any help is greatly appreciated!

As time goes by the chains that efectively connect the crank to the cam stretch. The tensioners continualy aply pressure on the chain to keep it taught. This keeps the cam timming correct, over time they could come out of time and then the danger of piston to valve contact is eminent.

Bruce Anderson's 'Porsche 911 Performance Handbook' probably does the best job of explaining the need for the update, and explaining the typical consequences of NOT catching the problem before damage occurs ... six bent intake valves, and six broken rocker arms can't be much fun to live thru!!!

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Warren Hall
1973 911S Targa