Cam Belt Allignment

[Cheese]

Changed my head gasket earlier in the week, and at the same time fitted a new cam belt. :)
Have set the belt 'correctly' in the centre of the top and bottom pullys and on the auto-tentioner and water pump. However when I start the engine the belt gradually move inwards (towards the block), and rubs gently on the top cam belt housing metal plate (the part thats attatched to the head). The belt obviously moves inwards on all 4 pullys.
Ive checked the water pump bearing and thats fine, the auto-tentioner has a very VERY tiny amount of play in the bearing, hardly noticable, but im going to pick up a new one this week to be on the safe side..
Top and bottom pullys are both fine.
Thinking that maybe the bolt for the auto-tentioner may be slightly bent (although it doesnt appear to be) causing it to sit at a slight angle, therefore pushing the belt inwards :?: :?:

It sat perfectly on the pullys before the gasket change and new belt, but I can't work out what why its now started moving :?: :?: :?:

Any ideas/suggestions :?: Its a 1990 1400 SR engine.

Thanks Ben

[brian]

is the metal cover bent? as long as the belt is fully on the pully (ie slightly to either edge or in the middle) it should not be in contact with anything :?

[techie]

Usually caused by water pump.

[Cheese]

Nope, the metal cover is fine, and straight. the belt is actually slightly off the pully towards the block, maybe 2-3mm. To be honest I think the plate is whats stopping it comming off completely! :o

Edit:
Ross, didnt move the water pump when changing the belt, and the bearing is fine! Can't understand why it moves! :?

[brian]

well if thats the case id be thinking the pump too as techie said

[Cheese]

Ok, will pick up a new water pump too, don't know if it will make any difference, but at least its one less thing to worry about.. :?

Cheers for the advice :D

[rgv_stu]

well if you didnt touch the pump then thats ok
did you take off the auto tensioner ?? cus you dont need to when changing the belt.
i had probs with tensioners and at ?60 for a new one i took it off and fitted the shorter belt