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Discussion Starter #1
Just been replacing the timing belt after rebuilding the cylinder head and having problems with the belt moving off the camshaft sprocket. When I turn the engine over by hand to settle the timing/pump belts and to make sure that the timing and belts etc...are running correctly, the timing belt keeps shifting to the left and overhanging the sprocket. The belt also starts to rub on the metal cover plate. Bottom pulley is done up tight, as is the camshaft sprocket. The belt and all tensioners were new 5000 miles ago. There is no play on either pulleys or tensioners. I've taken everything apart several times, but no joy. Has this happened to anyone else, or any ideas on a possible cause? As title says it's a 2.5acv engine.
 

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Discussion Starter #2
Forgot to mention that the lower toothed sprocket on the end of the crankshaft is also located correctly. Everything is lined up and no off angles.
 

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NOt sure if the same process as on the 1.9td but how did you align the head

On my 1.9 you align the head with 2 rods in the outer rear bolt holes.
I guess if head not aligned correctly the belt could be off the sprocket
especially if the rest lines up.

Mike
 

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Discussion Starter #4
Thanks Mike, same on mine all aligned with rods at back. So can't see how head is out! Something is obviously misaligned otherwise belt wouldn't move. I'm really at a loss. Spent halve a day messing with it. I'm wondering about the tensioner as this is the weaker point, but seems fine. Will need to replace stretch bolt on damper pulley yet again once problem sorted.
 

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Discussion Starter #8
When I took the belt off to do the cylinder head work I noticed it had been running slightly off. Now it's rubbing against the cover. Damper pulley fitted so obviously it can't move any further. Marmite, I will have to check the tensioner but don't have the old one. Everything else is as factory fitted. Maybe I need a new tensioner from vw. Thanks all for the thoughts.
 

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The belt may be faulty. If you remove it and turn it round so its rotating in the opposite direction, and it then it overhangs the pulley on the other side, the belt is not running true due to it being a very slight cone shape. If it still overhangs on the same side of the pulley, the belt's ok, and it must be something else out of alignment.

I fitted a brand new genuine belt on an Audi 90, and it wobbled from side to side, so it overhung on both sides of the pulley every belt rotation. Another new belt cured it.
 

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Ok, another thought, but a bit of a long shot, as I'm not sure it's possible, but could any of the cam bearing caps be in the wrong place thus pushing it sideways, or even the cam the wrong way round as it has tapered pulley mounts on each end?

It's been a good few years since I worked on one of these engines, so details are a little rusty!
 

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I can't remember what the top pulley is like on there but is it possible that it's been fitted around the wrong way? As in the inner edge is the outer edge etc if that makes sense?
 

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http://www.vwt4forum.co.uk/showpost.php?p=2051784&postcount=9

Just wandering the forum and came across this thread ^. He was supplied with the wrong water pump and the belt sits ours does. It's n a 2.4 AAB so maybe not relevant.

Does anyone know if all water pumps for the 2.5's are the same?

This is the kit I ordered and every thing was replaced, bolts the whole lot. http://www.mister-auto.ie/en/timing-belt-kit-with-water-pump/contitech-ct939wp3_g3096_a031CT939WP3.html Doesn't give a part number for the water pump supplied.


A bit worried now that I fitted the wrong pump.
 

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Discussion Starter #15
Thanks for all the replies so far. Can't get to look at my belt again until the weekend. Anyway, to answer some good questions.....

The camshaft can only go on the one way due to the vacuum pump lobe which is off centre and maybe other parameters.

The camshaft pulley can only go on one way due to the shape of the end of the camshaft and the shape of the pulley hole. There is a name for this but can't think at the moment.

The water pump was new 5000 miles ago when I changed the belts and tensioners.

All of the parts at that time came from Brickwerks and are good quality. I have replaced the damper pulley since then which is a GSF part (German oem quality). I still have the old damper pulley and will check to see if the inside edge is the same. This inside edge would hold the belt in position I presume.

The tensioner pulley and water pump pulley do not hold the belt in any sideways position and doubt whether these could influence sideways movement of the belt.

It is the crankshaft pulley and camshaft pulley either end that I presume govern the exact running of the belt. These would have to be in perfect alignment. So this weekend I intend to do some precise measuring, if that's possible.
 

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Discussion Starter #16


Hope this picture explains. Here the belt is on and pushed right back. As soon as I turn the engine over the belt moves away from the engine side and overhangs the top cambelt pulley. There is no play in the tensioner or water pump or the crank/ cam pulleys. With the damper pulley back on the belt still moves off. It overhangs the top cam pulley by 2mm, enough for the belt to rub on the metal cover lower down. Can't get van up and running until this mystery is solved. Scooby Doo where are you:*
 

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Discussion Starter #19
Crank pulley double and treble checked.

Some of these pulleys could do with a lip on them. Seen some Vag tensioners with a lip!

Waiting for the weekend now before I can check it all out again. I will have a go at slackening the tensioner a bit to see if the belt runs true. Only turning engine over by hand so not too worried about timing being a tad out at this stage. If belt runs true with a slack tensioner then the tensioner could be at fault!! Here's hoping it's this simple.
 

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Id try a new waterpump and tensioner - used parts are rarely a good idea when it comes to timing belts.
 
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