Automatic cam belt tensioning

The snag with letting the spring keep the tension is that if the engine reverses its direction of rotation, even very briefly (stalling on a hill start for example) there is a good chance that the timing will be lost. I believe there are engines out there where this does happen.

D A Stocks

Provided you turned the engine two turns clockwise after installation then all the slack will be on the tensioner side and the spring will put enough tension on for it to be safe. there are very few engines where the belt tension is very, very critical. The thing to avoid is overtight or overslack, there is quite a wide range between those which is quite ok If you are worried, then use the car for a few weeks and check, a good guide is to attempt to twist the belt with your fingers on the long front run of the belt, you should be able to twist it by a quarter turn approx.

Mrcheerful

If I have read your post correctly, this is one of those engines where the tensioner is pushed into contact with the belt by the spring, which sets it at the correct tension, and then the tightening the bolt prevents further movement, thus maintaining the correct tension. I'm not familiar with your engine, but I've seen engines with this arrangement, and any time you think it might need tensioning, you just slacken the bolt, which allows the tensioner to do it's stuff, and then retighten the bolt.

Steve

that is right, same as my Ferrari.