(Update.. :\) TURBO Ticking noise and misfire...

[MiniMental]

Howdy gents,

As some of you will know, I had the dreaded camshaft issue in December last year on my 1.9PD130 and rebuilt the top half of my cylinder head..

Its been 12k miles since and im developing a new issue which i suspect is related. It started a few months ago only when the car was cold after being stood overnight. When started, it would tickover fine or a little rough, then when it was revved at all or any load put on the engine, it would start juddering violently and missing a cylinder.. Its ticked since it was done a little as well. When it did this judder, it poured thick heavy grey smoke out the exhaust which smelt heavily of sickly, unburnt fuel....

This always cleared by letting it warm up before i set off and there was no issue once warm. It improved a little when the weather warmed up but was still there from time to time..

Now, it is significantly worse. everytime i start the car when its been stood cold, it misses and runs on three cylinders and i have to wait until its ran for 10 minutes before it will run properly. Even then, it seems down on power and the ticking is louder. Its also still a bit shaky and very smokey under heavy load. Even when hot now, when i boot it, it leaves a ton of whitish grey smoke behind it, enough that ive had headlights flashed.. It still pulls well when hot, but seems flat still.

I will point out, turbo seems to be fine. No excessive oil in IC and can hear it spool perfectly and smoothly. Never any funny noises or Limp mode etc so im ruling that out for now. It doesnt use it at idle anyways and the issue is still there when idling...

Injector loom was also replaced along with camshaft.

I have made a calculated guess at one of the following scenarios but can't pinpoint which as theyre al expensvieish to sort out and dont want to aim blind. I also get a fault code (cylinder 1 Misfire detected - intermittent). Cylinder 1 is the cylinder on which the tappet wore through the top and caused the brunt if the issue in december.

1. The exhaust valve or spring in cylinder 1 is damaged from the camshaft scenario and is sticking open. This is worse when cold as everything is tighter which is why it improves when hot. This would cause low compression, especially when speed is increased as it would then need to close faster, the low compression would in turn cause a misfire due to low compression and a lot of unburnt fuel pumped directly out of the exhaust through the stuck valve. The ticking noise is the valve finally snapping shut either when the piston taps it or of its own accord, who knows...

2. The injector is damaged on cylinder one and is misfuelling.. Cant see this as theyre apparently very reliable injectors and if it was misfueling it wouldnt be pumpin diesel out of the exhaust.

3. Piston rings are worn on cylinder one causing low compression, which would then cause a misfire.. Cant see this either as i would suspect it to be burning oil if they were that far gone.

I did think glowplugs but that wouldnt cause the other issues, esepcially one semi warm and revving high. When its happening, if i rev it above 1500rpm it either clears and runs smooth briefly until i release the pedal or feels like the engine is trying to flip the car upside down.. I dont strive to do this if im honest as it cant be good for the rest of the engine or my 12month old DMF...

I'm banking on option one in which case i would need to complete the head rebuild if im not mistaken. I would need to attain the following to achieve this...

1. Set of new valves
2. Full head gasket kit inc Valve stem seals, manifold gaskets etc
3. Valve guides
4. Coolant
5. Maybe some new valve springs?? At least a pair for cylinder one incase one broke when the tappet wore through...
A new stud for the timing tensioner? (Would this be really necessary, I fitted it only 8 months ago..)
6. Full set of head bolts
7. a nice dry day to do it on.

Ive already got assembly lube and a valve lapping kit as new valves would need bedding into the seats. Would also need a valve spring compressor to suit deep seated valves..

Any help or advice would be appreciated before i go tearing into my engine again. I have though about the simple stuff but dont want to start spending £40 here £30 there for the sake of it as it takes money out of my final budget...

Am i right in thinking the gearbox needs to be removed to drop the sump?

Cheers
Aidan