Engine Break in - Applying Moderate load

During Break in, we have also the valve lifters trying to be automatically filled with oil with time to allow smooth and accurate valves operation (Correct me if I am wrong); Applying a moderate load to the engine before this complete will develop a harsh tapping from the cams against the valve pockets (I did a rebuild once on an Mercedes M104 Engine and I could audibly hear it the first 1 hour of operation. Isn't this harmful ?

If you have hydraulic lifters then these should essentially pump up during the initial engine startup and achieve normal operation. This isn't something that should take an hour of running. I will add that the engine you've mentioned isn't one that I'm familiar with though so if you have more information to add then please do so.

Andre, Thank you always for the support!

The M104 is the German 2JZ as German fans like to call it. For my case, the ticking sound remained for almost an hour and asked another experienced engines builder with these engines, he said it's normal. Kindly advise