300TDI ticking noise-video included

1996 300TDI - video link below

Right, this noise started about 15mins after I had been driving, coming from the front left side when looking at the engine,
injection pump/timing case/area

no symptoms nothing,

drives fine, no loss of power no smoke, nothing.

just this ticking noise

I've cracked all the injectors,
changed the timing belt (local independent LR garage suspected tensioner bearing),
changed the timing belt, tensioner and idler,
had the vac pump off,
done all the valve clearances,

its not always on start up but usually after a few revs, it sounds to me like a marble in a glass jar,

its about 3-4 times a second at idle and gets louder with more revs,
no blow back from oil filler, no blowing at the back of the block, no oily water, nothing.

I'm at a loss, I really need the truck ASAP but don't want to drive it in case it fails or in case I'm doing more damage.

in the video you can hear it during the 4th rev and then on every time I rev it.

Any help much appreciated!

video link below

https://www.youtube.com/watch?v=CzJ1UhlekHQ

Possible cam follower, lift pump? but to me sounds more buzzy like injector pump.
Head off to get at followers.

My old ford had a worn cam that sounded like that .. only louder as engine was an ohc.. adjusting the tappets didn't make it quieter as the followers had worn through the hardened white metal and had worn a bad flat on the cam.. sounded bloody awful...

I've removed the lift pump which has stopped the noise however I need to wait on the replacement arriving before I can see if the cams worn!

They will run with dead or no lift pump as injector pump has its own vane fuel pump.

Yeah I might stick it back in so i have a running vehicle, I don't suppose if it is the cam that I can do anymore damage!

I had the exact same noise on my '96 300tdi. I replaced the vacuum pump which had about 7mm of free play on the plunger with a new one. On the new pump there is less than 3mm play.