I rebuilt my 2003 4d56T engine. At start up I have quite a bad rattle which sounds like top end. That rattle almost goes away after approx 10s of engine starting. Tappets are set to 0.25mm cold. Is that normal for these engines? No balance belt fitted. I check rocker arms and condition of the elephant feet and all good. What could I check? Is it normal that the oil pumps take a while to get oil around the engine in these?