I thought I'd have to mention my experiences on this forum.....

Having just changed one of the metal coolant pipes on my AKE engine (Coolant Loss topic). 'Peter D' advised me to change my Oil Retention valves, since I'd dismantled everything to do this.

I had never heard of these but they seem to retain the oil in the heads. I noticed the old valves were very worn and I could open them with my fingers.

Maybe this is one of the causes of the premature CAM wear........

Anyway, my engine is now quiet from cold, having been previously very noisy.