Stilo 1.2 Timing Belt Change

Sometimes the aligning and tensioning tools arent required. This causes a lot of, lets say, 'difference of opinion' between forum members. I'm dealer trained so i know all about special tools and why they are there and how to use them and all this and all that but if another cheaper, easier method is available that works equally as reliably then i don't see the point in spending hundreds of pounds aquiring the 'correct' tools.

Finding Cyl.1 TDC:-

You will require to set the engine to 'Top Dead Centre' on the 'Compression' stroke, to enable you to make your job a hell of a lot easier when fitting the timing belt.

• Remove the spark plug from cyl. 1 (the one nearest the timing belt).
• Shine a torch down the hole and watch for the valves to appear.
• You will each one come into view in turn first the exhaust and then the inlet almost immediately after the exhaust closes. (the valve that appears on the exhaust manifold side is the exhaust valve, the valve that appears on the inlet manifold side is the inlet valve.)
• Now go and watch the crank pulley for the markings as soon as it reaches 0, stop and mark the cam sprocket and head casing with tipex or something that wont rub off and is easy to see. you can mark the crank and block too if you like just to make it easier to see...

Aligning the Cam Sprocket

Sometimes you may find that the cam doesn't fully align with the new belt. this is because your old belt is stretched and as a result the positions between the cam and crank alter ever so slightly usually this will only be about 1/4 of a tooths width or less... to solve this all you have to do for the 1.2 engine is move the cam towards the crank and away from the tensioner by the desired amount to get it to engage on the teeth (twin cams are different you rotate them towards each other, rather than towards the crank, but don't worry about that for the 1.2 as it is a single cam engine)


Timing Belt Tension

This is quite important, too tight and you will end up causing damage to the water pump bearing/tensioner, too loose and the belt may 'jump a tooth' throwing your timing way out and possibly causing damage to valves and/or pistons. i good rule of thumb is to set the tension so that you are able to twist the timing belt between 45 and 90 degrees on its LONGEST run.
Too tight and usually the belt will 'whine' when the RPM increases.
Too loose and you will be able to see it 'flapping' on its longest run.


I think that's everything covered, feel free to message if you have any questions