Have you try turning the engine "clockwise" and "slowly" manually?
If its a piston hitting the valves you will fill it.

I just tried to change a chain on a different car last weekend, it was bad, really really bad... It kept jumping and I lost the timing... Thne the pistons were hitting the valves.
I was lucky with trial and error I put the old chain back where it was ...

Just to say you will feel it if its a valve.
Good advice to take the pump out too, might not be the right one? just to clear all possibility.

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E300TD year 2000. RUSTY SOLD
cost a fortune to maintain on the road
but run well on WVO
Second Merc died due to corrosion ( NOT rust) How can mercedes get away with that for so long?
Third lasted a month then went away...
Fourth now... Corroded too...