A recap, where we started and where to go next....
A data log from the evening before the noise. All seemed to run fine. We do have a bit of knock retard before shutting off, this could be normal, the exhaust on low RPM can rattle, I wouldn't be suprised if the engine sensors picked this up. Or is the noise a start of some mechanical issue?
Oil pressure not logged, there are limited amount of sensors you csn read per second, oil pressure wasn't a priority during tuning, but sure would have been handy if I did capture it in this log.
So the next day we both get in the car, turn it over, turns as normal, then a clonk, the clonk was so feirce it was like someone left a ratchet on the bottom pulley and it swang round and hit the chassis. The car shook. Had the engine jammed? I'm not trying it on the starter again until looking.
Pushed the car in the garage to take a look under the valve covers. I have had rocker issues in the past where a bolt came loose and the rocker would bank on the rocker cover. Was it top end valves? Got a ratchet on the bottom pulley and could turn the engine a full rotation, it was knackering.
The next day I tried manually turning the engine with no spark plugs in it. Far easier. Then happy to try it oin the starter again. Can hear a light banging noise, something in the engine by the sounds of it.
Removed the belt, to rule out every other thing on there, like power steeping, waterpump. Turning all of them by hand nothing odd. Jacked up car higher to get underneath.
Done a compression test to rule out piston to value collision, 205 - 215psi across all 8 cylinders.
Turning the engine by hand, I can feel resistance every two turns, I think I hear something but not sure, and it could be normal.
Getting the sump off I can look for bits of metal.
I may end up being the starter of something, the noise only happened on a starter, I cant turn the engine fast enough by hand to simular the starter speed. The noise seemed to have gone, perhaps what every caused a jam has broken down.
I think I need to look in the sump. Looks for signs of something banging? oil pump?
Oil pump does show no pressure, but with it being turned over so much without running then this could be normal.
Sump almost off, I'm changing the steering rack anyway, so this can be taken off and get out of the way, along with lowering the k-member to give the sump clearence for the removal.