Timing belt change on a Vauxhall Astra

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Mon 19 Dec 2005 09:50
Timing belt change on a Vauxhall Astra - wannabe mechanic
Hi there.

The timing belt snapped as i turned the key and attempted to start the car. Needles to say it didnt even fire so i think no damage will have been done. Am i right?

Ive stripped it down and removed the existing snapped belt and went and bought a new one ready to fit tonight. But ive never done a timing belt before and dont really know how to line everything up. There is a notch or arrow on both bottom and top pulleys. Do i just need to allign both of them at the top of the cycle i.e top dead centre? Then when the new belt is on do i need to put the car in 1st gear and turn one wheel in the air to make sure it all turns freely? Once its all done will i need to do the timing again?
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Mon 19 Dec 2005 11:18
Timing belt change on a Vauxhall Astra - Dynamic Dave
Needles to say it didnt even fire so i think no damage will have been done. Am i right?


8 or 16 valve engine? If an 8 valve, then more than likely you've got away with it. With 16 valve engines, pistons and valves will kiss one another. The fact that the engine didn't fire is not important. The engine was still rotating at the time and damage *could* have been done.

As for aligning up the timing marks, if it's a 16 valve engine, you'll need a cam locking tool. You need to align the notch on the pulleys up to the marks on the engine. From distant memory, at the crankshaft end there should be a pointer sticking out from the engine somewhere, and further marks on the cambelt cover to align the camshaft pulleys up to.

Best to rotate the engine using the bolt on the crankshaft. You'll have more control and should feel any resistance with the socket wrench rather than turning the wheel whilst in first gear.
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Mon 19 Dec 2005 11:25
Timing belt change on a Vauxhall Astra - wannabe mechanic
Very sorry, didnt realize i didnt specify the engine. Its a 1.4 8v astra gli. Hopefully this makes it easier and less probbability of a valve clash. Could you please advise me again about lining everything up for and 8v motor. Many thanks.
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Mon 19 Dec 2005 21:01
Timing belt change on a Vauxhall Astra - Dynamic Dave
From memory (distant) when I changed the cambelt on my old 8 valve Cavalier there was a timing mark on the camshaft cover (right at the top) which the notch in the camshaft sprocket has to line up with. At the crankshaft end there was a small peg sticking out from the engine in which the mark on the crankshaft sprocket has to line up with. IIRC, the marks on the sprockets were just a dot that were most probably made with a dot punch.
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