Hard knocking/ticking when deacceleration!!

[ADEN]

I finished 150km of the break in after engine rebuilt my engine developed a knocking at 3k rpm i didn't yet go beyond 3k but if i take off and reach 3k rpm car accelerate fine then when i let my foot slowly from the gas pedal i hear a hard knocking or maybe ticking sound from the engine (RPM speed noise) then i let my foot of the gas fully the noise stops, the same noise accures when i rev it to 3k when stationary.

It is driving me crazy stopped the car till i get it sorted out.

Note: Engine and tranny mounts are new . i noticed a play at the water pump pulley through my clutch fan i will take the fan off and test again. Is a worn watter pump can cause this issue?

[JehTehsus]

Is this a stock rebuild? If not, do you have an AFR log?

*edit if it only shows up above 3k RPM, possibly sync loss?

For example, around the 1k km mark on my new engine, I was accelerating from a stop (casually) and had some pretty serious banging/popping and knocking, as well as a definite momentary power loss. Nearly had a fucking heart attack, I thought for sure I had thrown a rod or something for a split second. Turned out to be a loss of sync on the megasquirt, which after getting home (about 200km of very cautious driving) I discovered likely came from a plug wire partially coming loose inside a boot and arcing a few times.

[ADEN]

No mine is stock rebuild.
i suspect valve to piston contact since i skimmed the head too much. Only checked for clearance by rotating the engine after assembly.

[ADEN]

I popped the head and this is what i found oil on cylinder #1 and i believe that intake valve is a problem what is causing this piston contact or valve is not closing properly?

[JehTehsus]

I popped the head and this is what i found oil on cylinder #1 and i believe that intake valve is a problem what is causing this piston contact or valve is not closing properly?

I think I recall seeing elsewhere you posted about machining some material off the head. Did you do a putty check during reassembly to validate valve clearances? Do you know how much material was originally present and how much was taken off?

I can't tell from that photo what state the valve is in; it seems somewhat low resolution or maybe slightly out of focus. Does it look like it contacted the piston? Is there a corresponding mark on the piston?

[ADEN]

I checked the piston and confirm no marks.
yes head was milled far beyond specs and oem hg used.