how many miles the engine done
have you had it set up properly
i have seen it on cars freshly built and all they needed was a set up
have you checked timing belt you have only got tobe out a bit and they tap and sound like your tappets are dry where in fact they are hitting the tops of pistons
is it a faint tapping could be the injectors i have had noisey ones before changed them and tapping went
or it could be where you have renewed the cam ,followers ect ect they do take a few miles to quieten down
needs looking at tobe safe so dont drive it and see if you can get it to a tuner
i aint no expert but trying to help
mark2