Timing Belt Tracking & touching rear cover.

Started the engine after a head rebuild & everything was fine but after a while I could hear a worrying noise ! The timing belt has tracked towards the rear (towards the head) & it is touching the rear cover about half way between the crankshaft & the exhaust cam sprocket.

I can't see any obvious way to adjust the belt tracking & all the rear cover bolts are tight. Any ideas ?

i would think either the belt is not on the crank pulley correctly, or the water pump is not right, or the tensioner pulley is not fitted square on its mounting.

The problem is that I am still not sure if the belt is too far back or the cover too far forward. I have seen photos on the forums where the cambelt is in the same position as mine. It does seem odd that there is no way of tracking the belt.

I am now tearing my hair out ! The cam sprockets & tensioner seem well aligned & I have taken off, checked & refitted the crank sprocket. But when I turn the engine I can see that the cambelt is tracking towards the back - I have just removed the rear cover to see how far the belt will travel.

Has anyone ever experienced anything like this ?