Engine knocking

[welshpug]

if you made a mistake when fitting the belt you would have a tap all the time, one thing to double check is that the crank bolt is done up tight enough, as this drives the oil pump.

tired tappets are not unheard of these days, and on a hot idle oil pressure will be lower especially on tired bearings, which will highlight a slightly sticking tappet, they can be dismantled and cleaned which will quieten most down.