I align with the pressure regulator idea. Try dropping the IP internal pressure by tapping the pin back the other way. Requires removal from pump to do so.
but apparently running a bigger pump head has an effect on timing some how, i would think it shortens the duration of the injection procress, which would actually advance timing in a way.
A 10mm pump will push more fuel then a 9mm pump in the same stroke due to the larger area and then having an AAZ camplate (steeper ramp than a 1.6 iirc) on it will push that extra fuel in there even faster.
The 10mm pump/AAZ camplate combination probably causes really sudden injection/combustion and the flame front smashing into the piston/cylinder walls is what is causing the noise.
I think I'd try finding a 1.6 camplate to fit and see what happens.
I am probably wrong, so please feel free to ignore/mock this post, but...
AAZ block (and Pistons) with a TDI head? Surely the piston tops are not shaped right to get the best possible combustion? The AAZ tops are designed to work with Precups, wheras eh piston on the TDI is shaped to facilitate DI?
Could well cause the noises?
I am probably wrong, so please feel free to ignore/mock this post, but...
AAZ block (and Pistons) with a TDI head? Surely the piston tops are not shaped right to get the best possible combustion? The AAZ tops are designed to work with Precups, wheras eh piston on the TDI is shaped to facilitate DI?
Could well cause the noises?

no it is an aaz head on a 1.6 block. the tdi head refers to the pump head on the injection pump
With the threat of a 100 mile drive (this Saturday) as it's first outing, I decided I couldn't take a chance on the pump as it was.
The clack sounded like it was doing some damage, so about 12:30 last night I decided to pull the pump and swap the 10mm head for a 9mm one.
By 2:30am it was stripped on the bench.

My boss sent me home an hour early today so I cracked on with the pump and got it built, then the kids came home and I got sidelined with making dinner, running a bath, making the beds, reading stories and other manly things.
It was nearly nine when I was ready to bleed the pump, but it wont

1 and 3 spit a bit, 2 and 4 are dry.
With 1 and 3 unions tightened it nearly starts but not quite, if it would start the pump would clear in a few minutes - I hope it's grease used for the assembly that is blocking things up.
What kind of "grease" are we talking here? Vaseline is what I use and it dissolves real quick in the diesel. Sounds like you are close. Hope you don't drain the battery cranking on it. That is where I generally get fouled up.
i wonder if maybe larger injectors would help with the bigger pump heads, possibly gm or mercedes. dave lost power when he swapped to dual stage aaz injectors, and i think they had the mercedes nozzles, but he also had a 9mm pump.
Hope you don't drain the battery cranking on it. That is where I generally get fouled up.
Kills the battery in about a minute, however owner a big jap diesel with a huge battery and a pair of truck jump leads means I can crank it until the starter motor melts.