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Cam belt not running centred

Posted: 24 Sep 2012, 20:24
by jas915
hi changed the cam belt on my AAZ conversion and although not started it only turned by hand the belt doesn't quite run in the centred of the pulleys(al of them) it runs on the edge nearest the engine. I did slide it back to centre but it returns. Have I done something wrong? It must have been centred before as you can see on the pulleys where it has been running.
Could it be the cam sprocket not on right?

thanks jason

Re: Cam belt not running centred

Posted: 24 Sep 2012, 21:18
by colinthefox
Did you change the tensioner at the same time? The tensioner MUST be changed with every new belt.

Could be a worn pump shaft too, but the first line of investigation should be the tensioner. Kind of difficult to explain, but if you try and re-use the spring loaded tensioner, the worn inside bearing can get all out of line.

I don't think the cam sprocket can be fitted out of true, as it's on a taper.

Re: Cam belt not running centred

Posted: 25 Sep 2012, 18:55
by jas915
thanks, i did put a new tensioner on.
think i will have to have a look another day, i think i may just take it off and refit it and see how it is.

Re: Cam belt not running centred

Posted: 25 Sep 2012, 19:01
by Oldiebut goodie
It more than likely run truer once it has run for a little while. Turning over by hand doesn't exactly give it chance to settle. Normally you would not notice when you change it as the cover would be back on to run the engine.

Re: Cam belt not running centred

Posted: 25 Sep 2012, 19:46
by jas915
maybe it will sort its self out once i run it, the engine hasn't been run for 3 months while iv been doing the conversion, hoping it will be finished this weekend so cam MOT it and use it :D

Re: Cam belt not running centred

Posted: 06 Oct 2012, 11:18
by max and caddy
There has been cases of this...vw issued a bulletin on it and it involves moving the pump bracket on the bolts...try a good google session and you may find the answer.

Re: Cam belt not running centred

Posted: 07 Oct 2012, 18:10
by jas915
thanks, its still the same after running, its going to the garage this week for an mot so i will see if they can fix it.or have any ideas

Re: Cam belt not running centred

Posted: 11 Oct 2012, 21:01
by jas915
just had a thought are the the belts directional? could i have fitted it backwards?. It a contitech one from brickwerks.
had a look online and could see anything to suggest they are directional.

thanks

Re: Cam belt not running centred

Posted: 11 Oct 2012, 21:26
by Oldiebut goodie
Not normally.

Re: Cam belt not running centred

Posted: 11 Oct 2012, 22:01
by Simon Baxter
Usually some clown has over tightened the tensioner, puts excess load onn the bearing in the injection pump.
bearing wears, makes the pulley "cock" over and belt runs off.

Re: Cam belt not running centred

Posted: 16 Oct 2012, 22:00
by max and caddy
Belt is not directional....pump is not the issue, bear with....off to google it.

Re: Cam belt not running centred

Posted: 17 Oct 2012, 18:53
by jas915
oh thanks let me know what you find out :ok

Re: Cam belt not running centred

Posted: 23 Oct 2012, 22:56
by max and caddy
Grrr! Can't find it anywhere...will keep looking but basically it involves removing the pump, loosening the console bolts and pushing it either up or down.....but that's the bit I forget...and re tightening.