I can't really see anything on oil pipes but haven't dismantled them.
As mentioned I have disassembled all 20 hydraulic tappets, cleaned them and assembled all in (still noise).
Last weekend I took off rocker when engine was cold and then when it was hot. On each occasion I checkedk each tappet for movement.
I found 4 that was spongy as if not filled. Hence they could be reason for noise.
So, off with camshaft and replaced 4 tappets. Reassembled and did valve timing (getting good training at this
But there's still noise :-(
So today I warmed up engine and removed rocker cover. I checked all tappets again - this time no-one is spongy - good.
Noise appears like this:
Cold engine, idle: clacking/knocking noise
After some 5mins, idle: noise gone and engine sounds nice!
After reaching working temp, idle: clacking/knocking noise (a bit better/softer sound than cold)
Warm, above 1100rpm: no noise
I don't think it's bottom end as it's clearly higher sound when i listen above engine (vs below).
This about difference when cold/warm and high/low revs could also point at oil viscosity?
I had used 10w-60 castrol sport oil. Maybe not good as 10w-40 recommended. Maybe too thin when hot?
I'm going to try std 10w-40...