Thanks for the replies.
Yes, original heads refitted, not sure what you mean by T vents? I would appreciate more information.
It is more of a rattle, than a knocking sound. I fitted the cambelt and tensioners. I bought a Laser locking kit and oof DVD and took my time to get cam timing on both banks spot on, but this is he first time I've done a cambelt. My previous experience with valve timing is ohc and pushrod motorbikes!

I was very careful on disassembly and assembly in this area and made lots of notes and sketches as I appreciate getting this wrong wreaks an engine. On disassembly as there are two lines on each sprocket, I marked the correct one with Tippex with crank at TDC, before I backed off to 60deg before TDC and removed cam belt and unbolted the sprockets. I made a drawing of cam peg position (so cam was approximately in the right place on assembly) and sprocket number, and labelled all of the cams and sprockets so they went back in the same place. I then made another diagram of cam bearing cap numbers before removing the cams. Likewise with the cam followers (I found egg boxes with labels ideal for holding the followers) so they all went back in the same place.
On rebuilding I refitted the cams, cambelt backing plate, then refitted and torqued up the sprocket bolts (new as they are stretch bolts) with the wife locking the cam with a 24mm spanner.

With the angle gauge torquing for the cam sprockets. I used one of the sprockets holes to lock the angle gauge, so if the cam moved a bit it would not matter as the angle turned was referenced to the cam. Next I positioned the cams and locked them with the red and green locking keys. I then turned the crank towards TDC added the locking tool and turned the crank the rest of the way so it was locked on water pump. The 'Gates' timing belt had white and yellow markings for crank and and cams 1 and 2. I compared to single marks on the old cam belt (just visible) and found the yellow were correct ones to use. The white won't line up anyway! Started to do the cam timing using the DVD, realising I couldn't get away without a 30mm spanner I left it for a couple of days, until one had been delivered by post (watched DVD a few more times so totally familiar with what I had to do

) and then timed up cam belt. Torqued up the tensioner bolts to 40nm while locking with 30mm spanner and set tensioner to edge of marker where a new belt. I couldn't get a socket on this with the allen key I was using so I could only tighten this up with a open ended spanner. Not ideal, but done up tightly!
Once I had done everything I double checked the timing with the Laser kit tool four times with 720deg rotation of the crank, with everything spot on each time.
