Update:
I put everything back together. The oil pan bolts that were hellish to get out were even worse getting back in. So much so that I just gave up and left them off, they were close to the other bolts anyway so I figured I'd risk it leaking and fix it if not, there was hardly anything in the way anyway.
It has been quite an adventure (horrible painful one I wish never happened). I put coolant and oil back in the engine, the coolant was a bit sketchy: engine started overheating a little while the coolant was flowing around but I pulled over, put more coolant in and it was ok since. Then came the fuel leak: I had to disconnect the HPFP while taking the camshaft girdle off and when I reconnected it I must not have tightened it enough. Trial and error after about 4 tries I got it all tight enough and no more fuel leak. I then noticed my MPG was still bad, thought it was weird but I was going on a little roadtrip so thought maybe it was the fuel leak earlier causing my MPG to still be so bad. Also at this time, I didn't remember how much power the car used to have but it did feel a bit different. I put it down to the tools I had in the back.
I waited 50 miles for the new belt to settle in before I gave it a pull, gave it full throttle in second gear and all was ok until about 4000rpm. The car suddenly lost power for a split second, gained it then lost it again then gained it. My brain immediately thought of the oil pan, I figured it had leaked oil onto the flywheel and caused the clutch to slip. It was then fine though, so it couldn't have been that. I got a blinking check engine light and this was a rural road so nowhere great to stop. The engine light went away pretty quickly so I just drove it slowly to the nearest town and took out the old Bluetooth code reader I left in the glove compartment. It gave me a couple misfire codes and an overboost code. I'm not sure what caused the overboost, maybe because it was running really rich but I thought it might be spark plugs (the new ones I put in were sitting in my toolbox for a year and they were cheap ridex ones I bought when I was new to cars) or coils or maybe a fuelling issue.
I drove back home and just decided to leave it and to baby the car for a bit while I figure out what it could be, I didn't need to drive much anyway. I drove about 10 miles away and on the way back I thought I'd try to replicate the issue again to maybe narrow some things down, maybe get some more information, but this time the engine misfired in second and it just kinda limped the entire way back. It ran really rough and I'm pretty sure it was just straight misfiring the whole time. At traffic lights I would manually keep the RPM at 2000 because I was worried it would stall and not turn back on. I'm not sure about stalling but after I got back home and got my laptop with VCDS out it did not turn on anymore. I thought damn, it's just cooked, I ruined my engine. I was pretty sure at this point it was a fuelling issue, I thought maybe my fuel pump was dying or maybe my filter was clogged since the symptoms matched but a couple days later I went to check the compression and the car actually turned on. I used VCDS to check the fuel rail pressure and it was seeming ok. I concluded I would throw spark plugs at it and hope that was the cause. I got some nice NGK spark plugs and the issue seemed to mostly go away, the fuel economy was back to normal, the power felt better and I didn't get any misfires in 2nd gear. I got one in 3rd gear but I couldn't test that much because obviously 5k RPM in 3rd gear is above the speed limit.
I took it out again today to see if it would be ok and I got the timing chain rattle again. This time it was there any time below 2500 RPM before the engine was warm. I checked for an oil leak and found none, I was going to check the oil level when I got home but my tyre actually ripped and I had to put the donut on. I got home but forgot to check the oil level and there's nowhere really level around so the rattle could be that, this engine does make the rattle when you have too little oil (and therefore pressure) which would explain why the noise went away above 2500 RPM(?). It could also be something to do with the VVT which would explain why the sound went away above 2500 RPM. It went away EXACTLY above 2500, on the dot, which seems important. Might be the oil pump I put on, might be the timing chain tensioner, might be the oil pump tensioner. I'll probably pull the timing case to check at some point.
Alas this car will have to sit for some time, I quit my job recently and can't just keep throwing money at it.
